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Performance Area => Peer Reviewed Studies Discussion => Topic started by: adarqui on March 12, 2010, 09:46:12 pm
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Studies pertaining to kaatsu / long duration isometrics / hypoxia / altitude training.
A given level of hypoxic conditions occur in traditional weightlifting etc, can include studies on that also.
whatever!
x. Muscle size and strength are increased following walk training with restricted venous blood flow from the leg muscle, Kaatsu-walk training
Previous studies have shown that low-intensity resistance training with restricted muscular venous blood flow (Kaatsu) causes muscle hypertrophy and strength gain. To investigate the effects of daily physical activity combined with Kaatsu, we examined the acute and chronic effects of walk training with and without Kaatsu on MRI-measured muscle size and maximum dynamic (one repetition maximum) and isometric strength, along with blood hormonal parameters. Nine men performed Kaatsu-walk training, and nine men performed walk training alone (control-walk). Training was conducted two times a day, 6 days/wk, for 3 wk using five sets of 2-min bouts (treadmill speed at 50 m/min), with a 1-min rest between bouts. Mean oxygen uptake during Kaatsu-walk and control-walk exercise was 19.5 (SD 3.6) and 17.2 % (SD 3.1) of treadmill-determined maximum oxygen uptake, respectively. Serum growth hormone was elevated (P < 0.01) after acute Kaatsu-walk exercise but not in control-walk exercise. MRI-measured thigh muscle cross-sectional area and muscle volume increased by 4–7%, and one repetition maximum and maximum isometric strength increased by 8–10% in the Kaatsu-walk group. There was no change in muscle size and dynamic and isometric strength in the control-walk group. Indicators of muscle damage (creatine kinase and myoglobin) and resting anabolic hormones did not change in both groups. The results suggest that the combination of leg muscle blood flow restriction with slow-walk training induces muscle hypertrophy and strength gain, despite the minimal level of exercise intensity. Kaatsu-walk training may be a potentially useful method for promoting muscle hypertrophy, covering a wide range of the population, including the frail and elderly.
x. Skeletal muscle size and circulating IGF-1 are increased after two weeks of twice daily “KAATSU” resistance training
This study investigated the effects of twice daily sessions of low-intensity resistance training (LIT, 20% of 1-RM) with restriction of muscular venous blood flow (namely “LIT-Kaatsu” training) for two weeks on skeletal muscle size and circulating insulin-like growth factor-1 (IGF-1). Nine young men performed LIT-Kaatsu and seven men performed LIT alone. Training was conducted two times / day, six days / week for 2 weeks using 3 sets of two dynamic exercises (squat and leg curl). Muscle cross-sectional area (CSA) and volume were measured by magnetic resonance imaging at baseline and 3 days after the last training session (post-testing). Mid-thigh muscle-bone CSA was calculated from thigh girth and adipose tissue thickness, which were measured every morning prior to the training session. Serum IGF-1 concentration was measured at baseline, mid-point of the training and post-testing. Increases in squat (17%) and leg curl (23%) one-RM strength in the LIT-Kaatsu were higher (p<0.05) than those of the LIT (9% and 2%). There was a gradual increase in circulating IGF-1 and muscle-bone CSA (both p<0.01) in the LIT-Kaatsu, but not in the LIT. Increases in quadriceps, biceps femoris and gluteus maximus muscle volume were, respectively, 7.7%, 10.1% and 9.1% for LIT-Kaatsu (p<0.01) and 1.4%, 1.9% and -0.6% for LIT (p>0.05). There was no difference (p>0.05) in relative strength (1-RM / muscle CSA) between baseline and post-testing in both groups. We concluded that skeletal muscle hypertrophy and strength gain occurred after two weeks of twice daily LIT-Kaatsu training.
x. The history and future of KAATSU Training
KAATSU training involves the restriction of blood flow to exercising muscle and is the culmination of nearly 40 years of experimentation with the singular purpose of increasing muscle mass. KAATSU Training consists of performing low-intensity resistance training while a relatively light and flexible cuff is placed on the proximal part of one's lower or upper limbs, which provides appropriate superficial pressure. KAATSU Training should not be confused with training under ischemic conditions which has previously been reported (Sundberg, 1994). KAATSU Training does not induce ischemia within skeletal muscle, but rather promotes a state of blood pooling in the capillaries within the limb musculature. Applied basic and clinical research conducted over the past 10 years has demonstrated that KAATSU Training not only improves muscle mass and strength in healthy volunteers, but also benefits patients with cardiovascular and orthopedic conditions.
x. Muscle fiber cross-sectional area is increased after two weeks of twice daily KAATSU-resistance training
The purpose of this study was to examine the effect of low-intensity (20% of 1-RM) resistance training (LIT) combined with restriction of muscular venous blood flow (KAATSU) on muscle fiber size using a biopsy sample. Three young men performed LIT-KAATSU (restriction pressure 160-240 mmHg), and two young men performed LIT alone. Training was conducted twice daily for 2 weeks using 3 sets of two dynamic lower body exercises. Quadriceps muscle CSA was measured by magnetic resonance imaging at midpoint of the thigh. Muscle biopsies were obtained from the vastus lateralis (VL) muscle using a needle biopsy. Mean relative change in 1-RM squat strength was 14% in the LIT-KAATSU and 9% in the LIT after two weeks of the training. Mean changes in quadriceps muscle CSA was 7.8% for LIT-KAATSU and 1.8% for LIT. Changes in muscle fiber CSA was 5.9% for type-I and 27.6% (p<0.05) for type-II in the LIT-KAATSU, and -2.1% and 0.5%, respectively, in the LIT. Mean fiber CSA changed 17.0% in the LIT-KAATSU, but not in LIT (-0.4%). We concluded that skeletal muscle and fiber hypertrophy, especially type-II fiber, occur after high frequency KAATSU training.
x. Muscle oxygenation and plasma growth hormone concentration during and after resistance exercise: Comparison between “KAATSU” and other types of regimen
We investigated the acute effects of “Kaatsu” resistance exercise and other types of exercise on muscle oxygenation and plasma growth hormone. Six young male bodybuilders performed leg extension exercise according to four exercise regimens: low-intensity [?30% of one repetition maximum (1RM)] exercise with moderate occlusion (LO-Kaatsu), low-intensity (?50% 1RM) exercise with slow movement and tonic force generation (3 s for lowering and 3 s for lifting actions, 1-s pause, and no relaxing phase; LST), low-intensity (same as LST) isometric exercise at 45° knee angle (ISO), and high-intensity (?80% 1RM) exercise with normal movement speed (HN), commonly used for gaining muscular size and strength. The muscle oxygenation level measured with near-infrared continuous-wave spectroscopy (NIRcws) showed the largest changes during and after LO-Kaatsu among all regimens. The minimum oxygenation level during LO-Kaatsu was the lowest among the four exercise regimens. On the other hand, the increases in muscle oxygenation after LO-Kaatsu were the largest among the four regimens. Plasma GH and blood lactate concentrations after LO-Kaatsu, LST and HN were significantly (P < 0.05) higher than those after ISO, but there were no significant differences among those after LO-Kaatsu, LST and HN. The results indicate that “Kaatsu” resistance exercise causes marked changes in muscle oxygenation level and circulating growth hormone, both of which may be related to muscular hypertrophy.
x. Hemodynamic and autonomic nervous responses to the restriction of femoral blood flow by KAATSU
KAATSU training is a novel method for strength training to induce muscle strength and hypertrophy. The purpose of the present study was to investigate the hemodynamic and autonomic nervous responses to the restriction of femoral blood flow by KAATSU. Ultrasonography, echocardiography and impedance cardiography were performed in ten healthy male volunteers aged 34 ± 1.5 before (pre), during and after (post) pressurization on both legs with KAATSU belts placed around proximal portion of both legs. The parameters measured were as follows; the superficial femoral arterial blood flow, left ventricular end-diastolic/systolic dimension (LVDd/LVDs), cardiac output (CO), stroke volume (SV), diameter of inferior vena cava (IVC), heart rate (HR), mean blood pressure (mBP), total peripheral resistance (TPR) and heart rate variability (HRV). The pressurization on both legs with KAATSU suppressed venous blood flow, and markedly induced pooling of blood into the legs with pressure-dependent reduction of femoral arterial blood flow. The application of 200 mmHg KAATSU decreased femoral arterial blood flow, LVDd, CO, SV and IVC significantly. HR tended to increase, and TPR increased significantly, but mBP did not change significantly. In addition, high frequency (HFRR), a marker of parasympathetic activity, decreased during KAATSU, while LFRR/HFRR, a quantitative marker of sympathetic autonomic nervous activity, increased significantly. These results indicate that the application of KAATSU on both legs induces venous pooling in the legs, and then inhibits venous return. The reduction of venous return causes a decrease of IVC diameter, cardiac size and stroke volume with an increase in TPR and LFRR/HFRR. Thus, the KAATSU training appears to become a useful method for potential countermeasure like lower body negative pressure (LBNP) against orthostatic intolerance for long-term bed rest or space flight as well as strength training to induce muscle strength and hypertrophy.
x. Hemodynamic and neurohumoral responses to the restriction of femoral blood flow by KAATSU in healthy subjects
Abstract The application of an orthostatic stress such as lower body negative pressure (LBNP) has been proposed to minimize the effects of weightlessness on the cardiovascular system and subsequently to reduce the cardiovascular deconditioning. The KAATSU training is a novel method to induce muscle strength and hypertrophy with blood pooling in capacitance vessels by restricting venous return. Here, we studied the hemodynamic, autonomic nervous and hormonal responses to the restriction of femoral blood flow by KAATSU in healthy male subjects, using the ultrasonography and impedance cardiography. The pressurization on both thighs induced pooling of blood into the legs with pressure-dependent reduction of femoral arterial blood flow. The application of 200 mmHg KAATSU significantly decreased left ventricular diastolic dimension (LVDd), cardiac output (CO) and diameter of inferior vena cava (IVC). Similarly, 200 mmHg KAATSU also decreased stroke volume (SV), which was almost equal to the value in standing. Heart rate (HR) and total peripheral resistance (TPR) increased in a similar manner to standing with slight change of mean blood pressure (mBP). High-frequency power (HFRR) decreased during both 200 mmHg KAATSU and standing, while low-frequency/high-frequency power (LFRR/HFRR) increased significantly. During KAATSU and standing, the concentration of noradrenaline (NA) and vasopressin (ADH) and plasma renin activity (PRA) increased. These results indicate that KAATSU in supine subjects reproduces the effects of standing on HR, SV, TPR, etc., thus stimulating an orthostatic stimulus. And, KAATSU training appears to be a useful method for potential countermeasure like LBNP against orthostatic intolerance after spaceflight.
x. Effects of low-intensity “KAATSU” resistance exercise on hemodynamic and growth hormone responses
Growth hormone (GH) is secreted in a pulsatile fashion during exercise, which promotes skeletal muscle growth and muscle strength. We compared the effects of different types of short-term low-intensity resistance exercise (STLIRE) on the hemodynamic and GH responses of men aged 20 to 45 years. Eleven untrained men performed 30 repetitions for 2 to 4 sets (mean 61 ± 7 repetitions) until fatigue for bilateral leg extension-flexion exercise (20% of 1 RM -Proteus Multi Exercise Machine) under the conditions of reduced muscle blood flow by applied pressure at the proximal ends of both legs by a specially-designed belt (Kaatsu Training). In the controlled exercise condition, without Kaatsu (n=9), subjects again performed the same exercise protocol as described above. Finally, a group of 5 men performed 3 sets of 10 repetitions using the Power Rehabilitation machine. Hemodynamic parameters were measured by using the impedance cardiography. Serum concentrations of GH, noradrenaline (NOR), and lactate were also measured. STLIRE with Kaatsu significantly increased GH, compared to STLIRE without Kaatsu. Maximal heart rate (HR) and blood pressure (BP) in STLIRE with Kaatsu were higher when compared to the control condition, however, stroke volume (SV) was lower compared to the controlled condition due to a decreased venous return induced by Kaatsu training. Total peripheral resistance (TPR) did not change significantly. The increase in NOR and lactate in STLIRE with Kaatsu was also significantly higher than without Kaatsu. These results suggest that “Kaatsu” leg resistance exercise caused a significant exercise-induced GH response even in STLIRE, with a reduction of cardiac preload during exercise. The results of the study indicate that Kaatsu training may become a unique method for rehabilitation in patients with cardiac diseases or low physical fitness.
x. Acute growth hormone response to low-intensity KAATSU resistance exercise: Comparison between arm and leg
Exercise is a potent stimulus to GH secretion. However it is unclear if exercise-induced GH release differs between different muscle groups, i.e., arm and leg exercise, when performed at equivalent exercise intensity. The purpose of this study was to compare the GH responses to an acute resistance exercise, combined with restriction of muscular venous blood flow (KAATSU), in muscle groups of the arm and leg. Five young male subjects performed two types of exercise tests, arm and leg exercise, on separate days. The intensity of exercise was 20% of 1-RM, which was measured at least 1 week before the experiment. The external restriction pressure during the KAATSU exercise was selected 50% higher than each measured-arm and estimated-leg systolic blood pressure. Venous blood samples were obtained prior to the start of exercise, immediately post exercise, and 15- and 60-min after exercise, and blood lactate (LA), growth hormone (GH), noradrenaline (NA), hematocrit, albumin and Na/K concentrations were measured. Significant elevations were apparent immediately post and 15-min after exercise for LA and at immediately post, 15- and 60-min after exercise for GH in both arm and leg exercise. Significant elevation was also observed after exercise for NA in both arm and leg, but leg exercise resulted in a greater increase in NA than arm at immediately post exercise. Change in plasma volume after exercise was not different between two exercises. These results suggest that GH secretory responses to exercise may be similar between the arm and leg when performed at equivalent exercise intensity and restriction stimulus.
x. KAATSU-walk training increases serum bone-specific alkaline phosphatase in young men
Previous research has shown that high intensity resistance training causes increases in bone density and increases in serum measures of bone turnover like bone-specific alkaline phosphatase (BAP). Medium intensity or low intensity training (like walking) does not result in these changes. However, low intensity training with blood flow restriction (KAATSU) has shown promise in bone and muscle rehabilitation settings. We hypothesized that there would be increases in serum BAP following low intensity KAATSU walk training. Healthy men walked on a treadmill twice per day (at least 4 hours between sessions) for 3 weeks with (KAATSU; n=9) or without (Control; n=9) blood flow occlusion pressure belts on their thighs. After three weeks of training, the KAATSU group experienced significant increases in MRI-measured muscle CSA (P<0.01), 1-RM muscle strength (P<0.01), and serum BAP levels (P<0.05). Percent change in BAP was 10.8% for the KAATSU-walk and 0.3% for the Control-walk. There was no significant change in serum IGF-1 for either group. We conclude that 3 weeks KAATSU walk training increases BAP, a serum marker of bone turnover.
x. Electromyographic responses of arm and chest muscle during bench press exercise with and without KAATSU
The purpose of this study was to compare the EMG activity of blood flow restricted (limb) and nonrestricted (trunk) muscles during multi-joint exercise with and without KAATSU. Twelve (6 women and 6 men) healthy college students [means (SD) age: 24.1 (3.5) yrs] performed 4 sets (30, 15, 15, and 15 reps) of flat bench press exercise (30% of a predetermined one repetition maximum, 1-RM) during two different conditions [with KAATSU and without KAATSU (Control)]. In the KAATSU condition, a specially designed elastic cuff belt (30 mm wide) was placed at the most proximal position of the upper arm and inflated to a pressure of 100% of individual's resting systolic blood pressure. Surface EMG was recorded from the muscle belly of the triceps brachii (TB) and pectoralis major (PM) muscles, and mean integrated EMG (iEMG) was analyzed. During 4 sets of the exercise, gradual increases in iEMG were observed in both TB and PM muscles for the KAATSU condition. The magnitude of the increases in iEMG in the TB and PM muscles were higher (P<0.05) with KAATSU compared to the Control condition. In the first set, the mean exercise intensity from normalized iEMG was approximately 40% of 1-RM in both Control and KAATSU conditions. However, the mean exercise intensity of both muscles were 60-70% of 1-RM for the KAATSU condition and only about 50% of 1-RM for the Control condition, respectively, during the fourth set. We concluded that increases in iEMG in the trunk muscle during KAATSU might be an important factor for KAATSU training-induced trunk muscle hypertrophy.
x. Eight days KAATSU-resistance training improved sprint but not jump performance in collegiate male track and field athletes
The purpose of this study was to investigate the effects of short-term KAATSU-resistance training on skeletal muscle size and sprint/jump performance in college athletes. Fifteen male track and field college athletes were randomly divided into two groups: KAATSU (resistive exercise combined with blood flow restriction, n=9) and control (n=6) groups. The KAATSU group trained twice daily with squat and leg curl exercises (20% of 1-RM, 3 sets of 15 repetitions) for 8 consecutive days while both KAATSU and control groups participated in the regular sprint/jump training sessions. Maximal strength, muscle-bone CSA, mid-thigh muscle thickness (MTH), and sprint/jump performance were measured before and after the 8 days of training. The muscle-bone CSA increased 4.5% (p<0.01) in the KAATSU group but decreased 1% (p>0.05) in the control group. Quadriceps and hamstrings MTH increased (p<0.01) by 5.9% and 4.5%, respectively, in the KAATSU group but did not change in the control group. Leg press strength increased (9.6%, p<0.01) in the KAATSU group but not (4.8%, p>0.05) in the control group. Overall 30-m dash times improved (p<0.05) in the KAATSU-training group, with significant improvements (p<0.01) occurring during the initial acceleration phase (0-10m) but not in the other phases (10-20m and 20-30m). None of the jumping performances improved (p>0.05) for either the KAATSU or control groups. These data indicated that eight days of KAATSU-training improved sprint but not jump performance in collegiate male track and field athletes.
x. Day-to-day change in muscle strength and MRI-measured skeletal muscle size during 7 days KAATSU resistance training: A case study
The purpose of this study was to examine the daily skeletal muscle hypertrophic and strength responses to one week of twice daily KAATSU training, and follow indicators of muscle damage and inflammation on a day-to-day basis, for one subject. KAATSU training resulted in a 3.1% increase in muscle-bone CSA after 7 days of training. Both MRI-measured maximum quadriceps muscle cross-sectional area (Q-CSA max) and muscle volume can be seen increasing after the first day of KAATSU training, and continuously increasing for the rest of the training period. Following 7 days KAATSU resistance training, the increases in Q-CSA max and muscle volume were 3.5% and 4.8%, respectively. Relative strength (isometric knee extension strength per unit Q-CSA max) was increased after training (before, 3.60 Nm/cm2; after, 4.09 Nm/cm2). There were very modest increases in CK and myoglobin after a single bout of KAATSU exercise in the first day of the training, but the values were return towards normal at 2 days after the training. IL-6 remained unchanged throughout the training period. In conclusion, our subject gained absolute strength and increased muscle size after only one week of low intensity KAATSU resistance training. Indicators of muscle damage and inflammation were not elevated by this training. KAATSU training appears to be a safe and effective method to rapidly induce skeletal muscle strength and hypertrophy.
x. Use and safety of KAATSU training:Results of a national survey
KAATSU training is a novel training, which is performed under conditions of restricted blood flow. It can induce a variety of beneficial effects such as increased muscle strength, and it has been adopted by a number of facilities in recent times. The purpose of the present study is to know the present state of KAATSU training in Japan and examine the incidence of adverse events in the field. The data were obtained from KAATSU leaders or instructors in a total of 105 out of 195 facilities where KAATSU training has been adopted. Based on survey results, 12,642 persons have received KAATSU training (male 45.4%, female 54.6%). KAATSU training has been applied to all generations of people including the young (<20 years old) and the elderly (>80 years old). The most popular purpose of KAATSU training is to strengthen muscle in athletes and to promote the health of subjects, including the elderly. It has been also applied to various kinds of physical conditions, cerebrovascular diseases, orthopedic diseases, obesity, cardiac diseases, neuromuscular diseases, diabetes, hypertension and respiratory diseases. In KAATSU training, various types of exercise modalities (physical exercise, walking, cycling, and weight training) are used. Most facilities have used 5-30 min KAATSU training each time, and performed it 1-3 times a week. Approximately 80% of the facilities are satisfied with the results of KAATSU training with only small numbers of complications reported. The incidence of side effects was as follows; venous thrombus (0.055%), pulmonary embolism (0.008%) and rhabdomyolysis (0.008%). These results indicate that the KAATSU training is a safe and promising method for training athletes and healthy persons, and can also be applied to persons with various physical conditions.
x. Muscle, tendon, and somatotropin responses to the restriction of muscle blood flow induced by KAATSU-walk training.
OBJECTIVE: The efficacy of KAATSU training has been demonstrated in human athletes, both as a therapeutic method as well as a training aid. The purpose of this study was to investigate the effects of slow walk training combined with restriction of muscle blood flow (KAATSU) on muscle and tendon size. METHODS: Six healthy, unfit Standardbred mares performed walking (240 m/min for 10 min and then 5 min recovery) with KAATSU, and 6 mares performed walking without KAATSU. A specially designed elastic cuff1 was placed at the most proximal position of the forelegs and inflated to a pressure of 200-230 mmHg throughout the walking and recovery sessions. The training was conducted once a day, 6 days/week for 2 weeks. Skeletal muscle thickness and tendon thickness were measured using B-mode ultrasound at baseline and after 2 weeks of training. Venous blood samples were obtained before the first acute exercise and 5, 15 and 60 min afterwards. Serum somatotropin concentration was determined using a commercially available equine-specific ELISA kit. RESULTS: The acute increase in plasma somatotropin was 40% greater (P<0.05) in the KAATSU-walk group than in the Control-walk group 5 min after exercise and remained elevated (P<0.05) at 15 and 60 min post exercise compared with the Control-walk group. After 2 weeks of training, muscle thickness increased (P<0.05) 3.5% in the KAATSU-walk group but did not change in the Control-walk group (0.7%). Tendon thickness did not change (P>0.05) in either group. CONCLUSIONS: These data demonstrate that KAATSU training can induce muscle hypertrophy in horses and suggest that KAATSU training may provide significant therapeutic/ rehabilitative value in horses, as has been shown in man.
x. Kaatsu training for patella tendinitis patient
Low-intensity Kaatsu resistance training performed by patients with moderate vascular occlusion is known to cause skeletal muscle hypertrophy over a short term. In our patients who used such training as a part of their rehabilitation, we have seen the same results, as well as a quenching analgesic effect. Herein, we report the effect of Kaatsu resistance training in a patient with patella tendinitis. The patient was a 17-year-old male who played basketball and came to us with intense pain at the lower edge of the patella in the right knee and was confirmed by an MRI image which showed a high intensity signal in the area of the patella tendon. Initially, we gave a dose of antiphlogistic analgetic, a steroid injection, and prescribed hospitalization for 1 month. Kaatsu resistance training was also recommended in an attempt to prevent muscle atrophy. The vascular occlusion point for the Kaatsu training cuff was the proximal end of the right limb, which had an occlusion pressure ranging from 160-180 mmHg. The exercise components that were used in combination with the Kaatsu training program were SLR, hip abduction, hip adduction, calf raise, toe raise, squat, crunch, back extension, and shooting. The exercise protocol was performed at about 30% of 1RM, with 3 sets of 15 repetitions, 5 to 6 times per week, for 3 weeks. T2 weighted MRI images (axial and sagittal) of the right patella tendon prior to beginning Kaatsu training showed high intensity signals, however, after 3 weeks of Kaatsu training, the signal intensity was reduced and the thigh circumference was increased by 7 mm and 2 mm for the right and left sides, respectively. Further, there was no evidence of muscle atrophy. The present patient was then treated with appropriate anti-inflammatory drugs and 1-month of hospitalization. During that time it was possible to completely relieve the inflammation and avoid muscle atrophy with Kaatsu training, and the patient quickly returned to playing basketball. In conclusion, this low-intensity resistance training was able to be performed without applying excessive load, which may have caused further damage, and we intend to use Kaatsu training with future patients to help them return as early as possible to full activities.
x. Effects of KAATSU training on haemostasis in healthy subjects
Purposes: The KAATSU training is performed under the reduction of muscle blood flow by a specially designed belt (KAATSU belt), which induces blood pooling in capacitance vessels by restricting venous return. However, no prior studies have examined the effects of KAATSU training on haemostasis. The purpose of the present study was to investigate acute effects of KAATSU training on haemostasis including fibrinolytic responses in healthy subjects. Methods: Two protocols have been performed. (1) 6 healthy men (mean age= 48 ± 5 yr) performed KAATSU (160 mmHg) of both thighs for 15 minutes and then KAASTU training combined with low-intensity leg and foot aerobic exercises for ? 10 minutes in hypobaric chamber, which mimics 8000 feet in airflight. (2) Another 7 men (mean age=30 ± 4 yr) performed leg press exercises (30 % 1 RM) with and without KAATSU of both thighs 24 h after bed rest. Blood samples were taken at rest, immediately after KAATSU, and exercises with or without KAATSU, and after exercise. For the investigation of blood fibrinolysis, determinations of tissue-type plasminogen activator (tPA) activity or antigen, plasminogen activator inhibitor (PAI)-1 activity or antigen, fibrin degradation product (FDP) and D-dimer were used. Prothrombin time (PT) and platelet counts were also measured. Results: (1) In hypobaric chamber, KAATSU by itself significantly increased tPA activity, while PAI-1 activity was unchanged. Furthermore, immediately after the exercise, tPA activity increased significantly. (2) During the exercises combined with KAATSU 24 h after bed rest, tPA antigen significantly increased, compared with control exercises, but PAI-1 antigen was unchanged. In both cases, KAATSU training did not induce fibrin formation as assessed by fibrin D-dimer and FDP. Conclusions: This study indicates that potentially favorable changes occur in fibrinolytic factors after KAATSU and KAATSU training in healthy subjects.
x. Overview of neuromuscular adaptations of skeletal muscle to KAATSU Training
Skeletal muscle adapts to a progressive overload, but the response can vary between different modes and intensities of exercise. Generally, a minimal threshold intensity of 65% of the one repetition maximum (1-RM) is needed to elicit muscle hypertrophy; however, recent studies have challenged this hypothesis and have provided evidence that low-intensity training (LIT) combined with vascular restriction (KAATSU) may also elicit increases in muscle size and strength. The physiological aspects of applying vascular restriction during exercise are not fully understood and may be explained by several factors. Examining the results of previous studies may help elucidate the factors responsible for the adaptations associated with vascular restriction in humans. Therefore, the objectives of this review are to summarize current knowledge regarding the physiological adaptations of skeletal muscle after low-intensity exercise combined with vascular restriction, the different training protocols used to elicit adaptations, and suggested areas for future research.
x. Effects of KAATSU on muscular function during isometric exercise
Generally, a threshold intensity of 65% 1-RM will induce muscle hypertrophy; however, recent studies using low-intensity (20% 1-RM) exercise combined with vascular restriction (KAATSU) have demonstrated increases in muscle size and strength. PURPOSE: To investigate the EMG and MMG responses, and percent voluntary activation (PVA) of the vastus lateralis (VL) following exposure to low-intensity intermittent isometric exercise in combination with moderate vascular restriction.METHODS: Twelve males (Age = 23.7 ± 4.1 yrs) participated in 1 familiarization trial and 2 experimental trials (with or without KAATSU) each separated by 48 h. Testing order was: a) Resting blood pressure after 5 min rest; b) 5 min warm-up on a cycle ergometer (50 W, 50-70 rpm); c) 2 preexercise 5-s isometric MVCs, 1 min rest between trials; d) 5 sets of 20 intermittent isometric contractions (2-s on / 1-s off) at 20% of MVC, 30-s interset rest periods; and e) 2 post-exercise isometric 5-s MVCs. RESULTS: There were no significant interactions or main effects for time or session for pre- and post-exercise isometric MVCs, with and without KAATSU, for the following parameters: MVC, PVA, EMG amplitude, EMG mean power frequency (MPF), MMG amplitude, and MMG MPF. Average normalized EMG amplitude increased significantly from repetitions 1-4 to 5-8 to 9-12 and MMG amplitude increased significantly from set 1 to 2 for both the KAATSU and no-KAATSU sessions. CONCLUSION: Intermittent isometric contractions at 20% 1-RM, with or without vascular restriction, are not intense enough to cause significant muscular fatigue.
x. Hemodynamic responses to simulated weightlessness of 24-h head-down bed rest and KAATSU blood flow restriction
Abstract The KAATSU training is a unique method of muscle training with restricting venous blood flow, which might be applied to prevent muscle atrophy during space flight, but the effects of KAATSU in microgravity remain unknown. We investigated the hemodynamic responses to KAATSU during actually simulated weightlessness (6° head-down tilt for 24 h, n = 8), and compared those to KAATSU in the seated position before bed rest. KAATSU was applied to the proximal ends of both the thighs. In the seated position before bed rest, sequential incrementing of KAATSU cuff pressure and altering the level of blood flow restriction resulted in a decrease in stroke volume (SV) with an increase in heart rate (HR). KAATSU (150–200 mmHg) decreased SV comparable to standing. Following 24-h bed rest, body mass, blood volume (BV), plasma volume (PV), and diameter of the inferior vena cava (IVC) were significantly reduced. Norepinephrine (NOR), vasopressin (ADH), and plasma renin activity (PRA) tend to be reduced. A decrease in SV and CO induced by KAATSU during the simulated weightlessness was larger than that in the seated position before bed rest, and one of eight subjects developed presyncope due to hypotension during 100 mmHg KAATSU. High-frequency power (HFRR) decreased during KAATSU and standing, while low-frequency/high-frequency power (LFRR/HFRR) increased significantly. NOR, ADH and PRA also increased during KAATSU. These results indicate that KAATSU blood flow restriction reproduces the effects of standing on HR, SV, NOR, ADH, PRA, etc., thus stimulating a gravity-like stress during simulated weightlessness. However, syncope due to lower extremity blood pooling and subsequent reduction of venous return may be induced during KAATSU in microgravity as reported in cases of lower-body negative pressure.
x. The use of anthropometry for assessing muscle size
The gold standard for assessing muscle size (cross-sectional area and volume) has been magnetic resonance imaging (MRI) and computerized tomography (CT), however, these processes are very expensive and generally require a medical facility, and in the case of CT, can involve exposure to high levels of radiation. The advent of B-mode ultrasound, in conjunction with simple anthropometric measures, such as circumference, can perhaps offer a quick, valid and reliable, and cost effective method to estimate muscle cross-sectional area (CSA) and track changes in muscle CSA following training. The purpose of this study was to document the reliability and accuracy of B-mode ultrasound in combination with anthropometry for assessing Kaatsu training induced changes in muscle-bone CSA. The data from thirty-three young men (mean age, 22.2 ± 5.1 yrs) in four different training groups were combined for the statistical analysis. All subjects were assessed prior to training and three days after the last training session. Anthropometric assessment of the right thigh circumference was taken at the mid point of the thigh (between the lateral condyle of the femur and greater trochanter), and midline anterior (QAT) and posterior (HAT) measures of subcutaneous adipose tissue thickness, at the same level as the circumference measures, was obtained with B-mode ultrasound. The muscle-bone CSA was estimated with the following equation: [? (r - (QAT + HAT) /2)2 ; r=circumference / 2?]. Each subject also had their right thigh imaged, at the same point as the circumference measure, by MRI. The estimated muscle-bone CSA was on average, 21% higher than the MRI measured CSA prior to training but the two methods were significantly (p<0.01) correlated (r=0.81). The correlation between the changes in estimated and MRI measured CSA due to muscle hypertrophy following Kaatsu training was also high (r=0.86) and significant (p<0.01) and only differed on average by 1.8% between two methods. In conclusion, it appears that anthropometry in combination with ultrasound can provide a reliable, accurate, and cost effective alternative method for assessing muscle hypertrophy.
x. Can KAATSU be used for an orthostatic stress in astronauts?: A case study
The application of an orthostatic stress such as lower body negative pressure (LBNP) during exercise has been proposed to minimize the effects of weightlessness on the cardiovascular system and subsequently to reduce the cardiovascular deconditioning. The KAATSU training is a novel method for strength training to induce muscle strength and hypertrophy. KAATSU induces venous pooling of blood in capacitance vessels by restricting venous blood flow. Therefore, to investigate whether KAATSU can be used as an orthostatic stress, we examined the effects of KAATSU on the hemodynamic, autonomic nervous and hormonal parameters in one subject. The several parameters were measured by impedance cardiography; heart rate (HR), mean blood pressure (mBP), stroke volume (SV), cardiac output (CO), total peripheral resistance (TPR), and heart rate variability (HRV). These data were obtained before (pre), during and after (post) pressurization (50 and 200 mmHg) on both thighs with KAATSU mini belts, and compared with those in standing. The serum concentration of noradrenaline (NA) and vasopressin (ADH), and plasma rennin activity (PRA) were also measured. The application of 200 mmHg KAATSU decreased SV, which was almost equal to the value in standing. HR and TPR increased in a similar manner as standing with slight change of mBP. High frequency (HFRR), a marker of parasympathetic nervous activity, decreased during both 200 mmHg KAATSU and standing, while LFRR/HFRR, a quantitative marker of sympathetic nervous activity, increased significantly. During KAATSU and standing, NA, PRA and ADH increased. These results indicate that the application of KAATSU on both thighs simulates systemic cardiovascular effects of orthostasis in one gravity (1G), and that KAATSU training appears to be a useful method for potential countermeasure like lower body negative pressure (LBNP) against orthostatic intolerance in space flight as well as strength training to induce muscle strength and hypertrophy.
x. Effects of a single bout of low intensity KAATSU resistance training on markers of bone turnover in young men
Traditional high intensity resistance exercise programs have been shown to have positive effects on bone metabolism. KAATSU resistance training, which combines low intensity resistance exercise with vascular restriction, accelerates muscle hypertrophy, however, the benefits of this type of training on bone have not been established. PURPOSE: To investigate the effects of acute (1 bout) KAATSU training for knee extensors and knee flexors on serum bone biomarkers in young men, 18-30 years of age. METHODS: Nine males performed two test sessions, KAATSU (vascular restriction + low intensity resistance exercise) and control (low intensity resistance exercise only) 48 hours apart in random order. The exercise protocol consisted of 1 set of 30 reps followed by 3 sets of 15 reps with 30 seconds rest between sets at 20% 1-RM for both muscle groups. On both days, fasting blood draws were obtained immediately prior to exercise, immediately post exercise and 30 minutes post exercise for the measurement of the bone formation (bone-specific alkaline phosphatase, BAP) and bone resorption (cross-linked N-telopeptide of type I collagen, NTx) markers. Hematocrit was measured at each sample time to estimate plasma volume changes. Serum samples were aliquoted and frozen at -70°C until the BAP (Metra BAP EIA kit, Quidel Corporation) and NTx (Osteomark® NTx Serum, Wampole Laboratories) assays were performed. RESULTS: KAATSU training resulted in greater plasma volume decreases (p<.05) immediate post exercise compared to the control session. There was a significant (p<.05) training x time effect for NTx levels. 30 minute post exercise NTx levels (21.4±3.4 nM BCE) significantly (p<.05) decreased from baseline (24.9±4.3 nM BCE) after KAATSU training but not in response to the control training. After correcting for plasma volume shifts, significant decreases in serum NTx were observed for both KAATSU post exercise samples. There were no significant (p>.05) training or time effects for BAP. CONCLUSION: A single bout of KAATSU trining resulted in decreases in the bone resorption marker (NTx) but had no effect on the bone formation marker (BAP). The NTx response to KAATSU was not mediated by shifts in plasma volume.
x. KAATSU resistance training decreased the sinus pause in a patient demonstrating sick sinus syndrome. A case report
The effectiveness of KAATSU resistance training (Kaatsu) has been established as a method not only to increase muscle size and power but also to benefit patients with orthopedic and cardiac diseases. The method is a low-intensity resistance exercise (20?30% of one repetition maximum, 1RM) with a restriction of the venous return using a specially designed pressurized cuff or belt at the proximal end of the upper or lower extremities. The increases of growth hormone (GH) and insulin-like growth factor-1 (IGF-1) by Kaatsu resistance training are considered to play an important role in elucidating the mechanism of Kaatsu. In this case, the sinus pause of a patient with sick sinus syndrome (SSS) decreased to approximately 40% with Holter ECG monitoring after Kaatsu resistance training. The mechanism regarding such an improvement by Kaatsu is herein discussed. Therefore, an additional effect of Kaatsu is reported concerning the decreased sinus pause observed in a SSS patient.
x. Resistance exercise combined with KAATSU during simulated weightlessness
The application of a gravity-specific stress (e.g. LBNP), in combination with exercise, prevents cardiovascular deconditioning in space flight. KAATSU training is a method to induce blood pooling in capacitance vessels by restricting venous return (as with LBNP) and which when combined with low-intensity resistance (RE) exercise produces remarkable muscle mass and muscle strength gains. The purpose of this study was to investigate the hemodynamic and neurohumonal responses induced by KAATSU in combination with leg RE (30 % 1 RM), during simulated weightlessness (6°head-down tilt for 24 h, n=7). Following 24 h bed rest 6° head-down tilt, body mass was decreased from 75.3 ± 3.9 to 73.3 ± 3.8 Kg (P<0.01). Blood volume (BV) and plasma volume (PV) were reduced by ?4.4 ± 1.4% and ?7.9 ± 2.5%, respectively. During RE, BV and PV were significantly decreased; the changes with KAATSU induced a lower-body venous pooling, resulting in a sustained decrease in stroke volume (SV; from 77.0 ± 4.4 ml to 55.9 ± 5.1 ml; P<0.01) that was comparable to resting SV while standing. Consequently, RE heart rate (HR) was greater with KAATSU. The serum concentrations of plasma renin activity (PRA), vasopressin (ADH), noradrenaline (NOR), and lactate were also significantly elevated during RE with KAATSU as compared to control RE. These hemodynamic and neurohumoral responses following head-down tilt and during RE closely approximate the gravity-specific stress observed with LBNP. Thus, when used in combination with RE, KAATSU may be a useful countermeasure in microgravity.
x. Effect of knee extension exercise with KAATSU on forehead cutaneous blood flow in healthy young and middle-aged women
Dynamic exercise induces changes in the redistribution of whole-body organ-tissue blood circulation, including cutaneous blood circulation. We hypothesized that limb exercise combined with the restriction of muscular blood flow (KAATSU) may influence cutaneous blood flow redistribution. To examine this hypothesis, forehead (supraorbital) cutaneous blood flow was compared in women performing exercises with and without KAATSU. Ten young and middle-aged female subjects in the supine position performed three sets of 15 repetitions of unloaded unilateral knee extension exercises (30-s rest between sets). Blood flow was calculated from blood velocity and red blood cell mass (blood flow = velocity * mass) determined by laser blood flowmetry. While exercise without KAATSU did not induce alterations in velocity and mass (hence, no alterations in blood flow) throughout the entire exercise series, exercise with KAATSU induced increases (P<0.05) in blood flow owing to increases in velocity. These increases were not eliminated during the rest periods between exercise sets. Heart rate (HR) increased (P<0.05) with the second and third sets of exercises with KAATSU compared with HR before exercise initiation, and was higher than the HR resulting from a corresponding set of exercises without KAATSU. There were no changes in blood lactate and hematocrit in both types of exercises. Norepinephrine increased (P<0.05) at the completion of the exercise sets. These results suggest that forehead cutaneous blood circulation was increased by unloaded KAATSU leg exercise.
x. The horse: An alternative model for KAATSU research
In order to produce significant muscle hypertrophy, a training intensity of greater than 65% of the 1-repetition maximum (1-RM) is generally believed to be required. However, this concept has been challenged recently by data from studies that have combined 20%-50% 1-RM with restriction of venous blood flow from the working muscle, referred to as KAATSU-training. These studies have demonstrated significant gains in muscle size and strength in as little as 2 weeks in humans. The KAATSU-training model may have utility in models other than humans; several recent papers have investigated the safety and potential utility of KAATSU-training in an equine model. The purpose of this brief review is to discuss the horse as a viable model of KAATSU-training and discuss the available data using this model thus far.
x. Blood pressure response to slow walking combined with KAATSU in the elderly
The purpose of the present study was to examine the blood pressure and heart rate response to walking with and without blood flow restriction (KAATSU-walk) in the elderly. Seven active subjects (2 men, 5 women) aged between 64 to 78 years (mean age, 68.9 ± 6.3 years) performed walking test without (Control) and with KAATSU (cuff pressure 160 mmHg and 200 mmHg) on separate days. The exercise consisted of level walking at 67 m/min (4 km/hr) for 20 min. Systolic (SBP) and diastolic (DBP) blood pressure was recorded using an automatic blood pressure monitor, and mean arterial pressure (MAP) was calculated [MAP = DBP + (SBP - DBP)/3]. Heart rate (HR) and ratings of perceived exertion (RPE) were also recorded during the test. There were no significant differences (P>0.05) in blood pressure responses between the Control and KAATSU-160mmHg exercise, however significantly higher blood pressures were observed for the KAATSU-200mmHg exercise (112-127mmHg for MAP) compared to the Control. However, these values are still lower than those of previous reported during moderate to heavy resistance exercise. The correlations between HR and MAP during each exercise condition were all statistically significant (range from r=0.83 to r=0.94; p<0.05). However, the intercept of the curve was highest in KAATSU-200mmHg exercise (i.e. MAP response to the same HR was higher), suggesting the increased total peripheral resistance with high occlusive pressure. In conclusion, our results indicate that during slow walk exercise with KAATSU, level of occlusive pressure can significantly impact upon the HR and MAP responses in the elderly, These findings are consistent with the idea that the occlusive pressure by itself can significantly modulate the cardiovascular response during low-intensity KAATSU-walk.
x. Effects of Whole-Body Low-Intensity Resistance Training With Slow Movement and Tonic Force Generation on Muscular Size and Strength in Young Men
Our previous study showed that relatively low-intensity (~50% one-repetition maximum [1RM]) resistance training (knee extension) with slow movement and tonic force generation (LST) caused as significant an increase in muscular size and strength as high-intensity (~80% 1RM) resistance training with normal speed (HN). However, that study examined only local effects of one type of exercise (knee extension) on knee extensor muscles. The present study was performed to examine whether a whole-body LST resistance training regimen is as effective on muscular hypertrophy and strength gain as HN resistance training. Thirty-six healthy young men without experience of regular resistance training were assigned into three groups (each n = 12) and performed whole-body resistance training regimens comprising five types of exercise (vertical squat, chest press, latissimus dorsi pull-down, abdominal bend, and back extension: three sets each) with LST (~55-60% 1RM, 3 seconds for eccentric and concentric actions, and no relaxing phase); HN (~80-90% 1RM, 1 second for concentric and eccentric actions, 1 second for relaxing); and a sedentary control group (CON). The mean repetition maximum was eight-repetition maximum in LST and HN. The training session was performed twice a week for 13 weeks. The LST training caused significant (p < 0.05) increases in whole-body muscle thickness (6.8 ± 3.4% in a sum of six sites) and 1RM strength (33.0 ± 8.8% in a sum of five exercises) comparable with those induced by HN training (9.1 ± 4.2%, 41.2 ± 7.6% in each measurement item). There were no such changes in the CON group. The results suggest that a whole-body LST resistance training regimen is as effective for muscular hypertrophy and strength gain as HN resistance training.
x. Acute Hormonal Responses To Restriction Of Leg Muscle Blood Flow During Walking: 564 Board #155 2:00 PM - 3:30 PM
11 male college students performed walking (50 m/min for five 2 min bouts; 1 min rest between bouts) with and without KAATSU (the proximal end of their thigh compressed at 130% of resting systolic blood pressure throughout the walking session) on separate days. Venous blood samples were obtained prior to the start of exercise (Pre), and immediately (IP), 15- (15P) and 60-min (60P) after exercise.
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RESULTS
Serum GH concentration was elevated (P<0.01) from Pre [1.72 (0.83) ng/ml] to IP [12.4 (3.2) ng/ml] and 15P [13.1 (2.4) ng/ml] in the walking with KAATSU. Free testosterone was also elevated (P<0.05) from Pre [12.7 (1.2) pg/ml] to IP [16.0 (1.3) pg/ml] in the walking with KAATSU. Neither GH [Pre, 1.67 (0.97) ng/ml; IP, 1.39 (0.91), 15P, 1.26 (0.92)] nor free testosterone [Pre, 14.3 (1.3) pg/ml; IP, 14.1 (1.2)] increased during the walking without KAATSU. Cortisol concentration showed a gradual decrease (P<0.05) during the experiments in both walking with and without KAATSU.
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CONCLUSIONS
The results of the present investigation with young male students indicated that slow walking with KAATSU caused greater responses in serum GH and free testosterone compared to normal slow walking.
x. Muscle Oxygenation and Pulse Oxygen Saturation during Walking Combined with Restriction of Leg Muscle Blood Flow: 2708: Board #216 3:PM - 4:PM
We reported that chronic walk training combined with restriction of leg muscle blood flow (KAATSU) increases thigh muscle size and strength. A variety of factors are thought to influence the KAATSU walk-induced muscle hypertrophy, such as enhanced endocrine responses and muscle oxygenation status. Although the precise mechanism is not fully understood, oxygenation status of working muscle seems to play an important role in stimulation of KAATSU-induced muscle hypertrophy.
PURPOSE: To investigate the response of leg muscle oxygenation and pulse oxygen saturation during KAATSU walk.
METHODS: Seven young men [mean (SD) age: 22.1 (2.9) yrs] performed acute treadmill walking with (KAATSU-walk) and without KAATSU (Control-walk) on same day. The exercise consisted of walking at 50 m/min for five 2-min bouts, with a 1-min rest between bouts (total time 14 min). A specially designed elastic belt (50 mm wide) was placed around the most proximal portion of each leg during KAATSU-walk exercise. The belt contained a pneumatic bag along its inner surface that was connected to an electronic air pressure control system that monitored the restriction pressure (Kaatsu-Master, Tokyo). The belt air pressure was set at 200 mmHg for the restriction stimulus during KAATSU-walk test. A near-infrared continuous-wave spectroscopic monitor (NIRS) was used to measure the peripheral muscle oxygenation in the vastus lateralis (VL) and gastrocnemius medialis (MG) muscles. Pulse oxymetry (SpO2) was monitored in both the hands and feet. Oxygen uptake during KAATSU-walk and Control-walk was measured on separate days.
RESULTS: Mean heart rate was higher (P < 0.05) at the latter half of the walking session in the KAATSU-walk than in the Control-walk. Mean oxygen uptake was higher (P < 0.01) in the KAATSU-walk (687 ml/min) than in the Control-walk (612 ml/min). There was no difference in SpO2 (both hand and foot) during KAATSU-walk than during Control-walk (97?99%). On the other hand, muscle oxygenation level was lower (-16.4%; P < 0.01) in the VL (54.4 ± 6.9% versus 65.1 ±5.2%) and was lower (-17.1%; P < 0.01) in the MG (51.0 ± 7.5% versus 61.5 ± 3.2%) during KAATSU-walk than during Control-walk, respectively.
CONCLUSION: The lower muscle oxygenation level during KAATSU-walk may be one of the key factors for the muscular hypertrophy. The decrease in muscle oxygenation was, however, likely due to the pooling of venous blood in the working KAATSU muscle. Further study is needed to determine whether muscle is hypoxic during KAATSU-walk exercise.
x. Effects of Walk or Squat Training Combined with Restriction of Leg Muscle Blood Flow on Hip, Thigh and Calf Muscle Hypertrophy: 1773: Board # 146 3:00 PM - 4:00 PM
Low-intensity resistance squat or walk training combined with restriction of leg muscle blood flow (KAATSU) increases thigh muscle size and strength. However, it is unknown whether muscle hypertrophy occurs in training movement-related accessory muscles, such as hip and calf, following KAATSU squat or walk training.
PURPOSE: To investigate the effects of 2 types (walk or squat) of exercise training combined with KAATSU on hip, thigh and calf muscle size and strength.
METHODS: 33 healthy young men [mean (SD) age: 22.4 (3.5) yrs] were randomized into 4 training groups: treadmill walking (50m/min, 5 sets of 2-min bout with a 1 -min rest between bouts, twice per day, 6 days per week for 3 weeks) with or without KAATSU (KAATSU-walk, n=9 or Control-walk, n=8), and squat exercise (20% of 1-RM, 4 sets, twice per day, 6 days per week for 2 weeks) with or without KAATSU (KAATSU-squat, n=9 or Control-squat, n=7). A specially designed elastic belt (50 mm wide) was placed around the most proximal portion of each leg during training with KAATSU. The belt contained a pneumatic bag along its inner surface that was connected to an electronic air pressure control system that monitored the restriction pressure. Because the subjects adapted to the occlusion stimulus during the training, the restriction pressure of 160-230 mmHg was selected for occlusive stimulus. Skeletal muscle volume was measured using magnetic resonance imaging (MRI) 1.5 T-scanners with spin-echo sequence. Contiguous transverse MRI images (about 100 slices) with a slice thickness of 1 -cm were obtained from the L4/L5 to the ankle joint before and after training. Quadriceps, gluteus maximus, and triceps surea muscle volume were calculated from the summation of digitized cross-sectional area. Maximum isometric knee extension strength was measured before and after training.
RESULTS: There were no changes (P >0.05) in muscle volume and maximum isometric strength for Control-walk and Control-squat groups. Maximum isometric knee extension strength increased (P <0.05) 11.1% for KAATSU-squat and 10.4% for KAATSU-walk. Quadriceps muscle volume increased (P <0.01) 4.1% and 7.5%, respectively, in KAATSU-walk and KAATSU-squat groups. Gluteus maximus muscle volume increased 8.4% (P <0.01) in KAATSU-squat but did not increase in KAATSU-walk (-0.6%). On the other hand, triceps surea muscle volume increased (P <0.05) 5.7% in KAATSU-walk but did not increase (P >0.05) in KAATSU-squat (1.2%).
CONCLUSION: Skeletal muscle hypertrophy occurred not only thigh muscle, but also in training movement-related accessory muscles following low-intensity KAATSU training.
x. Effects of Vascular Restriction on Muscular Function during Intermittent Submaximal Isometric Exercise: 2246: Board #159 June 1 8:00 AM - 9:30 AM
It is generally accepted that a threshold intensity of 65% 1-RM is needed to induce muscle hypertrophy; however, recent studies using low-intensity resistance exercise (20% 1-RM) combined with vascular restriction (KAATSU) have also been able to demonstrate increases in muscle size and strength.
PURPOSE: To investigate EMG and MMG responses of the vastus lateralis (VL) before, during, and after low intensity intermittent isometric exercise in combination with moderate vascular restriction and to examine the percent voluntary activation (PVA) of the VL.
METHODS: Twelve healthy males volunteered to participate in this study (mean + SD age = 23.7±4.1 years). Each participant visited the laboratory 3 times: one familiarization trial and two experimental trials, separated by at least 48 h. The two experimental trials consisted of the same testing and isometric exercise protocol; however, the participants experienced either the KAATSU or no-KAATSU conditions in random order. For the experimental trials, the following procedures were performed in order: a) Resting blood pressure assessment after 5 min rest (for the KAATSU trial only), b) five-minute warm-up on a stationary cycle ergometer with a power output of 50 W and a pedaling cadence of 50-70 rpm, c) two pre-exercise 5-s isometric MVCs with 1 min rest between trials, d) five sets of 20 intermittent isometric contractions (2-s on and 1 -s off) at 20% of MVC with a 30-s interset rest period, and e) two post-exercise isometric 5-s MVCs with 1 min rest between trials.
RESULTS: For MVC torque, PVA, EMG amplitude, EMG mean power frequency (MPF), MMG amplitude, and MMG MPF, there was no interaction and no main effects for time or session for the pre- and post-exercise isometric MVCs with and without KAATSU. The average normalized EMG amplitude (%MVC) increased from repetitions 1-4 to 5-8 to 9-12 and MMG amplitude increased significantly from set 1 to 2 for both the KAATSU and no-KAATSU sessions.
CONCLUSIONS: The present study demonstrated no significant change in post-exercise torque values and % activation, suggesting that the exercise task was not intense enough to cause muscular fatigue in either treatment condition.
x. Proposal of alternative mechanism responsible for the function of high-speed swimsuits
Since many top swimmers wearing Speedo LZR Racer swimsuits have broken world records, it is considered that the corset-like grip of suit supports the swimmers to maintain flexibility of movement and reducing water resistance. We propose an alternative mechanism to explain this phenomenon. The suits are so tight that the blood circulation of swimmers is suppressed. This effect accelerates the anaerobic glycolysis system but rather suppresses the aerobic mitochondrial respiration system. Because of the prompt production of ATP in the glycolysis system, the swimmers, especially in short distance competitions, obtain instantaneous force in white fibers of the skeletal muscles.
x. Muscle Hypertrophy following Multi-joint Low Intensity Resistance Training with Single-joint Blood Flow Restriction: 1615: Board #162 May 28 3:30 PM - 5:00 PM
Low-intensity, single-joint resistance exercise training combined with restricted muscle blood flow results in significant increases in muscle size and strength. What remains poorly understood is whether muscle enlargement and strength changes occur in lowintensity multi-joint exercise where only a portion of the active musculature is exposed to restricted blood flow.
PURPOSE: To determine the impact of low-intensity multi-joint resistance exercise on strength and the hypertrophic response of muscles proximal (non-restricted) and distal (restricted) to blood flow restriction (KAATSU).
METHODS: Bench press training (30% of 1-RM, 4 sets, 30 sec rest between sets) was performed with (BP-K; n=5) and without (BP-C; n=5) KAATSU blood flow restriction; the proximal end of their upper arm compressed at 80-120% of resting systolic blood pressure throughout the exercise session. Training was conducted twice per day, six days per week for 2 weeks. Each morning prior to the training session, triceps brachii and pectoralis major muscle thickness (MTH) were measured by B-mode ultrasound (Aloka SSD-500, Tokyo). Serum creatine phosphokinase, myoglobin, growth hormone, testosterone, insulin-like growth factor (IGF)-1 and IGF-BP3 concentrations were measured prior to and 2-days following the last training session.
RESULTS: There were no changes in anabolic hormones or serum markers for muscle damage in either group. 2-weeks of training led to a significant increase (P<0.05) in 1-RM bench press in BP-K (+6%), but not in BP-C (-2%). Triceps and pectoralis major MTH increased 8% (pre, 36.1 mm; post 38.9 mm, P<0.01) and 16% (pre, 23.7 mm; post, 27.6 mm, P<0.01), respectively, in BP-K, but not in BP-C (-1% and 2%, respectively).
CONCLUSIONS: Low-intensity Kaatsu training involving a multi-joint exercise leads to a significant increase in muscular strength and hypertrophy in skeletal muscles proximal and distal to the blood-flow restriction; suggesting that the mechanism of KAATSU training affects adaptation upstream and downstream of the pressure cuff and blood flow restriction.
x. Neuromuscular Fatigue during Low-Intensity Dynamic Exercise in Combination with Externally Applied Vascular Restriction: 1768: Board #121 May 29 9:00 AM - 10:30 AM
PURPOSE: The present study investigated neuromuscular fatigue during lowintensity resistance exercise (i.e., 20% 1RM) combined with (KAATSU) and without (control, CON) vascular restriction.
METHODS: Fourteen healthy males (mean + SE age= 23.7±1.1 years) volunteered to perform 2 pre-exercise isometric maximum voluntary contractions (MVCs) before and after 5 sets of 20 dynamic constant external resistance (DCER) leg extension exercises at 20% of 1RM. During one of the two trials seperated by at least 48 hours, vascular restriction (KAATSU) was applied to the proximal thighs using pneumatic cuffs (50 mm wide) connected to an electronic pressure control system. No KAATSU was aplied to the CON condition. Surface electromyography (EMG) was recorded from the vastus lateralis during all MVCs and the DCER leg extensions. Twitch interpolation was used to assess the percent of maximal voluntary activation (%VA) during the MVCs.
RESULTS: After the KAATSU condition, the decreases (p<0.05) in MVC force, %VA, EMG amplitude, and potentiated twitch force were more profound than the changes observed after the CON condition. However, during the DCER exercises, the increases (p<0.05) in EMG amplitude and decreases (p<0.05) in EMG mean power frequency were similar for both the KAATSU and CON conditions.
CONCLUSIONS: These findings indicated that low-intensity leg extension exercises at 20% 1RM combined with KAATSU resulted in a greater post-exercise fatigue effect than the CON condition, despite the similar EMG changes during the DCER exercises. Our findings suggest that the KAATSU-induced fatigue may have been due to a combination of peripheral and central manifestations.
x. Skeletal muscle size and strength are increased following walk training with restricted leg muscle blood flow: implications for training duration and frequency
The purpose of this study was to investigate once-daily walk training with restricted leg blood flow (KAATSU) on thigh muscle size and strength. Twelve young men performed walk training: KAATSU-walk training (n=6) and control (no KAATSU-walk; n=6). Training was conducted once daily, 6 days per week, for 3 weeks. Treadmill walking (50 m/min) was performed for 5 sets of 2-min bouts interspersed with 1-min rest periods. The KAATSU-walk group wore pressure cuff belts (5 cm wide) on both legs during training, with incremental increases in external compression starting at 160 mmHg and ending at 230 mmHg. Thigh muscle volume and isometric and 1-repetition maximal (1-RM) strength were measured before and after training. In the KAATSU-walk group, quadriceps and hamstrings muscle volume increased 1.7 and 2.4% (both P<0.05), respectively, following training. One-RM leg press and leg curl increased 7.3 and 8.6% (both P<0.05), respectively, following KAATSU-walk training. Also, isometric knee extension strength (4.4%; P<0.01), but not knee flexion strength (1.7%), increased following KAATSU-walk training. There were no changes in muscle volume or strength in the control-walk group. These results confirm previous work showing that the combination of slow walk training and leg muscle blood flow restriction induces muscle hypertrophy and strength gains. However, the magnitude of change in muscle mass and strength following once-daily KAATSU-walk training was approximately one-half that reported for twice-daily KAATSU-walk training over a 3-week period. These results in combination with previous observations lead to the conclusion that the impact of KAATSU-walk training on muscle size and strength is related to an ability to accomplish a high number of training bouts within a compressed training duration. Second, frequency-dependent muscle enlargement appears to be associated with KAATSU-walk training.
x. Muscle Tissue Oxygenation and Force Production during Low-intensity Resistance Exercise with Blood Flow Restriction: 1769: Board #122 May 29 9:00 AM - 10:30 AM
We have recently demonstrated that an acute bout of low-intensity resistance exercise combined with blood flow restriction (Kaatsu exercise) stimulates both muscle protein synthesis and translation initiation. Recently, myocardial ischemia-reperfusion has also been shown to activate the signaling pathway of translation initiation.
PURPOSE: To investigate the changes in muscle tissue oxygenation during Kaatsu exercise to assess the level of ischemia-reperfusion condition in skeletal muscle.
METHODS: Six subjects performed three separate experiments randomly; Control (CON), Kaatsu (KAT, blow restriction via pressure cuff), or High-intensity (HI) exercise group. CON and KAT performed a bout of unilateral knee extension exercise at 20% of 1-repetition maximum (1-RM) strength, while HI group exercised at 70% 1-RM. Vastus lateralis and rectus femoris muscle tissue oxygenation (HbO2) was assessed using near-infrared spectroscopy (NIRS), and isometric muscle strength was assessed immediately before and after the exercise bout.
RESULTS: In the KAT, resting HbO2 was reduced significantly (rest, 61.7%; cuff, 54.5%; p<0.05) in response to blood flow restriction. During exercise, HbO2 decreased further in KAT and reached the same level of tissue oxygenation as HI (KAT, 45.6%; HI, 44.8%; p<0.05 vs. rest for both groups) whereas HbO2 did not change in CON. During the recovery period, HbO2 was restored to the resting level both in CON and HI group (63.9 and 69.1% for CON and HI, respectively), whereas it was still significantly depressed in KAT group (51.4%, p<0.05). Muscular strength was significantly reduced after the bout of exercise in KAT and HI (-45 and -25% for KAT and HI, respectively; p<0.05), whereas no change in strength was observed in CON (-1.8%).
CONCLUSION: Although a decreased tissue oxygenation during exercise and recovery period may contribute to muscle fatigue, sustained ischemic condition during recovery period in KAT suggests a non-significant ischemia-reperfusion during low intensity resistance exercise with blood flow restriction.
x. Effects of short-term, low-intensity resistance training with vascular restriction on arterial compliance in untrained young men
Previous studies have shown that low-intensity resistance training with restricted blood flow, known as KAATSU training, increases muscle strength and size. Its effects on blood vessel function, however, have not been examined. We compared the effects of a short-term KAATSU resistance training protocol and traditional high-intensity resistance training on muscle strength and blood vessel function in young, untrained men. Male volunteers were randomly assigned to a KAATSU resistance training group (KR, n=10), a traditional resistance training group (RT, n=10), or a KAATSU-only group (K, n=10). Both KR and RT groups trained 3 times per week for 3 weeks doing leg press (LP), knee flexion (KF), and knee extension (KE) isotonic resistance exercises. Training sessions consisted of 5-10 min of warm-up, followed by 2 sets of 10 repetitions at 80% of 1 repetition maximum (1-RM) for the RT group, while the KR group performed the resistance exercises with vascular restriction at a load of 20% of 1-RM. The K group had only the vascular restriction treatment for 3 weeks. Muscle strength (1-RM) and arterial compliance (pulse contour analysis) were assessed at baseline and after training. Both the KR and RT groups did not show changes in arterial compliance of the large or small arteries (P>0.05) after training. There were significant time effects (P<0.05 pre- vs. posttraining); however, resistance training generally resulted in greater relative improvements in strength. Arterial compliance of the large and small arteries was not affected by the either the KAATSU or traditional high-intensity resistance training interventions.
x. Circuit training without external load induces hypertrophy in lower-limb muscles when combined with moderate venous occlusion
The present study investigated whether circuit training with body weight alone (no external load) can cause muscular hypertrophy when combined with moderate venous occlusion (‘Kaatsu Training’). Healthy women (mean age, 32.7 ± 4.0 yr; n=22) were randomly assigned into the occlusive training group (OCC, n=11) and the normal training group (NOR, n=11). Both groups performed the same circuit-training regimen consisting of six, successive exercises for muscles in the upper and lower limbs and the trunk, at a frequency of 3 sessions/wk. Each session lasted for 5-10 min. In OCC group, proximal ends of the upper and lower limbs of both sides were moderately compressed by means of ‘KAATS Sportswear’, to restrict the venous blood flow during the exercises (preset pressure, 50-80 mmHg and 80-120 mmHg for upper and lower limbs, respectively). Cross-sectional area (CSA) of the thigh muscle was measured with spiral computer tomography. After an 8-wk period of training, the muscle CSA of both right and left limbs showed significant increases by ?3% (P<0.05) in the OCC group, whereas there was no change for the NOR group. To propose a mechanism for these findings, the acute effects of the same exercise regimen combined with occlusion on plasma concentration of growth hormone (GH) were further investigated with male subjects (n=2). The circuit exercise with occlusion elicited a dramatic increase in plasma GH, whereas that without occlusion did not, although statistical analysis could not be made. The results indicate that circuit training with only body weight can cause hypertrophy in lower-limb muscles when combined with moderate venous occlusion, but the exact mechanism is not yet understood.
x. Fatigue Characteristics during Maximal Concentric Leg Extension Exercise with Blood Flow Restriction
Low-intensity resistance exercise combined with blood flow restriction has been shown to elicit hormonal and neuromuscular responses similar to those with high-intensity resistance exercise. However, muscle fatigue characteristics during resistance exercise with restricted blood flow have not been clarified. Therefore, we measured maximal voluntary torque values during isokinetic concentric leg extensions across 30 repetitions at 180°/s either with blood flow restriction (BFR) or without restriction (CON) in eight healthy adults. The exercise was performed at the rate of either 30 repetitions/minute (BFR30 and CON30) or 15 repetitions/minute (BFR15 and CON15) designed to allow different rest intervals between contractions. Muscle fatigue was quantified by two methods: slope of peak isokinetic torque values through the 30th repetition and percent decrease in force from the first 5 repetitions to the last 5 repetitions. At the rate of 30 repetitions/minute, both fatigue rates were similar between BFR and control group. On the contrary, both fatigue rates were significantly higher in BFR15 group than the CON15 group (p<0.05). The results indicate that during resistance exercise performed with longer inter-repetition rest intervals, blood flow restriction is more effective at inducing muscle fatigue and thus may increase the training response. Furthermore, inter-repetition rest intervals of less than 3.5 seconds can increase fatigue level regardless of muscle perfusion.
x. The Effects Of Differing Thigh Composition On Tissue Oxygenation Of The Quadriceps Following Vascular Restriction: 1822: Board #172 May 27 2:00 PM - 3:30 PM
KAATSU is a new training technique which can utilize different initial pressures (ranging between 30 and 70 mmHg) prior to an incremental increase in pressure to restrict blood flow during exercise, however it has not been investigated if tissue oxygenation would be affected by the composition of the restricted limb.
PURPOSE: To examine the effects of subcutaneous fat and lean muscle mass on tissue oxygenation of the quadriceps muscles while using three different initial restriction pressures.
METHODS: Six healthy males (30.0±4.6 years) had their thigh size measured by circumferences, skinfolds, ultrasound, and dual energy x-ray absorptiometry (DXA) to determine volume and thickness of subcutaneous fat and regional bone free muscle mass. Following skin preparation, Near-Infrared Spectroscopy was placed over the mid-thigh to measure tissue oxygenation. The KAATSU belt was placed on the upper most portion of the thigh, and participants then experienced initial pressures of 30, 50, and 70 mmHg in random order on three separate days. Tissue oxygenation was recorded at rest (lying down) once initial pressure was set, then following six pressures (120, 140, 160, 180, 200, and 220 mmHg) were sequentially applied to restrict blood flow for 4-min with 2-min rest periods between trials without pressure. Pearson correlations explored relationships between variables with the level of significance set at 0.05.
RESULTS: Correlations between leg LBM and tissue oxygenation were significant and strong (r= 0.87 to 0.97) when initial pressure was set at 70 mmHg, however, there was only minimal association with subcutaneous fat. A significant positive correlation was detected between tissue oxygenation and thigh circumference at 70 mmHg (r= 0.85), however when the restriction pressure was increased, correlations became were non-significant and moderate in nature (r= 0.58 to 0.78). Tissue oxygenation was generally inversely or weakly related to thigh circumference (r= -0.62 to 0.32), subcutaneous fat (r= -0.53 to 0.41), and leg LBM (r= -0.45 to 0.34) when initial pressures were set at 30 and 50 mmHg.
CONCLUSIONS: The findings indicated that when using the highest initial restrictive pressure of 70 mmHg, tissue oxygenation was positively correlated with leg muscle mass due to greater blood pooling.
x. Increased muscle volume and strength following six days of low-intensity resistance training with restricted muscle blood flow
Traditional high-intensity resistance training performed 2-3 times per week induces muscle hypertrophy, at least, in 5 weeks (i.e. 10-15 training sessions). To examine the effect of a higher training frequency (12 sessions in 6 days), healthy young men performed low-intensity resistance training with (n=8, LIT-BFR) and without (n=8, LIT-CON) leg blood flow restriction with cuff inflation (BFR) twice per day for 6 days. Training involved 4 sets of knee extension exercise (75 total contractions) at 20% 1-RM. Significant muscle hypertrophy was observed only in the LIT-BFR group as estimated muscle-bone cross-sectional area (CSA) (2.4%), MRI-measured mid-thigh quadriceps muscle CSA (3.5%) and quadriceps muscle volume (3.0%) increased. The resulting hypertrophic potential (% change in muscle size divided by number of training sessions; ?0.3% per session) is similar to previously reported traditional high-intensity training (0.1 to 0.5% per session). Improved 1-RM knee extension strength (6.7%) following LIT-BFR training was accounted for by increased muscle mass as relative strength (1-RM/CSA) did not change. There was no apparent muscle damage associated with the exercise training as blood levels of creatine kinase, myoglobin, and interleukin-6 remained unchanged throughout the training period in both training groups. A single bout of training exercise with and without BFR produced no signs of blood clotting as plasma thrombin-antithrombin complex, prothrombin fragment 1,2 and D-dimer were unchanged. In conclusion, changes in muscle mass and strength following 6-day (12 sessions) of low-intensity resistance training requires BFR to produce responses comparable to the effect of several weeks of high-intensity resistance training.
x. Effects of Exercise Load and Blood-Flow Restriction on Skeletal Muscle Function
Resistance training at low loads with blood flow restriction (BFR) (also known as Kaatsu) has been shown to stimulate increases in muscle size and strength. It is unclear how occlusion pressure, exercise intensity, and occlusion duration interact, or which combination of these factors results in the most potent muscle stimulus.
Purpose: To determine the effect of eight BFR protocols on muscle fatigue (decrement in maximal voluntary contraction (MVC) after the performance of exercise), and to compare the decrement in MVC with the currently recommended resistance exercise intensity (~80% MVC).
Methods: During five test sessions, 21 subjects (14 males and 7 females, 27.7 ± 4.9 yr) completed nine protocols, each consisting of three sets of knee extensions (KE) to failure. One protocol was high-load (HL) exercise (80% MVC) with no BFR, and the other eight were BFR at varying levels of contraction intensity (20 or 40% MVC), occlusion pressure (partial (~160 mm Hg) or complete (~300 mm Hg)), and occlusion duration (off during the rest between sets or continuously applied). To evaluate each protocol, MVC were performed before and after exercise, and the decrement in force was calculated.
Results: Three sets of KE at 20% MVC with continuous partial occlusion (20%ConPar) resulted in a greater decrement in MVC compared with HL (31 vs 19%, P = 0.001). None of the other BFR protocols were different from the HL protocol, nor were they different from 20%ConPar (P > 0.05).
Conclusion: All BFR protocols elicited at least as much fatigue as HL, even though lower loads were used. The 20%ConPar protocol was the only one that elicited significantly more fatigue than HL. Future research should evaluate protocol training effectiveness and overall safety of BFR exercise.
x. Effects of Vascular Occlusion on Muscular Endurance in Dynamic Knee Extension Exercise At Different Submaximal Loads
Strength training with low load under conditions of vascular occlusion has been proposed as an alternative to heavy-resistance exercise in the rehabilitation setting, when large forces acting upon the musculoskeletal system are unwanted. Little is known, however, about the relative intensity at which occlusion of blood flow significantly reduces dynamic muscular endurance and, hence, when it may increase the training effect. The purpose of this study was to investigate endurance during dynamic knee extension at different loads with and without cuff occlusion. Sixteen subjects (20-45 years of age) with strength-training experience were recruited. At 4 test sessions, the subjects performed unilateral knee extensions to failure with and without a pressure cuff around the thigh at 20, 30, 40, and 50% of their 1 repetition maximum (1RM). The pressure cuff was inflated to 200 mm Hg during exercise with occlusion. Significant differences in the number of repetitions performed were found between occluded and nonoccluded conditions for loads of 20, 30, and 40% of 1RM (p < 0.01) but not for the 50% load (p = 0.465). Thus, the application of a pressure cuff around the thigh appears to reduce dynamic knee extension endurance more at a low load than at a moderate load. These results may have implications regarding when it could be useful to apply a tourniquet in order to increase the rate of fatigue and perhaps also the resulting training effect. However, the short- and long-term safety of training under ischemic conditions needs to be addressed in both healthy and less healthy populations. Furthermore, the high acute pain ratings and the delayed-onset muscle soreness associated with this type of training may limit its potential use to highly motivated individuals.
x. The effects of low-intensity resistance training with vascular restriction on leg muscle strength in older men
Abstract The purpose of this study was to investigate and compare the effects of two types of resistance training protocols on the adaptation of skeletal muscle strength in older men. Thirty-seven healthy male subjects (50–64 years) participated in this study. Subjects were assigned to one of three groups: high-intensity (80% 1-RM) resistance training (RT80); low-intensity (20% 1-RM) resistance training with vascular restriction (VR-RT20); and a control group (CON) that performed no exercise. Subjects in both exercise groups performed three upper body (at 80% 1-RM) and two lower body exercises either with (20% 1-RM) or without (80% 1-RM) vascular restriction three times a week for 6 weeks. As expected, the RT80 and VR-RT20 groups had significantly (p < 0.01) greater strength increases in all upper body and leg press exercises compared with CON, however, absolute strength gains for the RT80 and VR-RT20 groups were similar (p > 0.05). It should be noted that the percentage increase in leg extension strength for the RT80 group was significantly greater than that for both the VR-RT20 (p < 0.05) and CON groups (p < 0.01), while the percentage increase in leg extension strength for the VR-RT20 group was significantly (p < 0.01) greater than that for the CON. The findings suggested that leg muscle strength improves with the low-load vascular restriction training and the VR-RT20 training protocol was almost as effective as the RT80 training protocol for increasing muscular strength in older men.
x. Neuromuscular fatigue following low-intensity dynamic exercise with externally applied vascular restriction
This study investigated neuromuscular fatigue following low-intensity resistance exercise with vascular restriction (VR) and without vascular restriction (control, CON). Fourteen males participated in two experimental trials (VR and CON) each separated by 48 h. Each participant performed two isometric maximum voluntary contractions (MVCs) before and after five sets of 20 dynamic constant external resistance leg extension exercises (DCER-EX) at 20% of one-repetition maximum (1-RM). The participants were asked to lift (1.5 s) and lower (1.5 s) the load at a constant velocity. Surface electromyography (EMG) was recorded from the vastus lateralis during MVC and DCER-EX. Twitch interpolation was used to assess the percent of maximal voluntary activation (%VA) during the MVC. During performing five sets of 20 DCER-EX, the increases (p < 0.05) in EMG amplitude and decreases (p < 0.05) in EMG mean power frequency were similar for both VR and CON. However, there were significant differences between VR and CON for MVC force, %VA, and potentiated twitch force and significant interactions for EMG amplitude. VR decreased MVC force, %VA, potentiated twitch force, and EMG amplitude more than CON. Our findings suggest that the VR-induced fatigue may have been due to a combination of peripheral (decreases in potentiated twitch) and central (decreases in %VA and EMG amplitude) fatigue.
x. Cross-Transfer Effects of Resistance Training with Blood Flow Restriction
Purpose: This study investigated whether muscle hypertrophy-promoting effects are cross-transferred in resistance training with blood flow restriction, which has been shown to evoke strong endocrine activation.
Methods: Fifteen untrained men were randomly assigned into the occlusive training group (OCC, N = Cool and the normal training group (NOR, N = 7). Both groups performed the same unilateral arm exercise (arm curl) at 50% of one-repetition maximum (1RM) without occlusion (three sets, 10 repetitions). Either the dominant or nondominant arm was randomly chosen to be trained (OCC-T, NOR-T) or to serve as a control (OCC-C, NOR-C). After the arm exercise, OCC performed leg exercise with blood flow restriction (30% of 1RM, three sets, 15-30 repetitions), whereas NOR performed the same leg exercise without occlusion. The training session was performed twice a week for 10 wk. In a separate set of experiments, acute changes in blood hormone concentrations were measured after the same leg exercises with (N = 5) and without (N = 5) occlusion.
Results: Cross-sectional area (CSA) and isometric torque of elbow flexor muscles increased significantly in OCC-T, whereas no significant changes were observed in OCC-C, NOR-T, and NOR-C. CSA and isometric torque of thigh muscles increased significantly in OCC, whereas no significant changes were observed in NOR. Noradrenaline concentration showed a significantly larger increase after leg exercise with occlusion than after exercises without occlusion, though growth hormone and testosterone concentrations did not show significant differences between these two types of exercises.
Conclusion: The results indicate that low-intensity resistance training increases muscular size and strength when combined with resistance exercise with blood flow restriction for other muscle groups. It was suggested that any circulating factor(s) was involved in this remote effect of exercise on muscular size.
x. Effect of resistance exercise training combined with relatively low vascular occlusion
Previous studies have demonstrated that a low-intensity resistance exercise, combined with vascular occlusion, results in a marked increase in muscular size and strength. We investigated the optimal pressure for reduction of muscle blood flow with resistance exercise to increase the muscular strength and endurance. Twenty-one subjects were randomly divided into four groups by the different application of vascular occlusion pressure at the proximal of thigh: without any pressure (0-pressure group), with a pressure of 50mmHg (50-pressure group), with a pressure of 150mmHg (150-pressure group), and with a pressure of 250mmHg (250-pressure group). The isokinetic muscle strength at angular velocities of 60 and 180°/s, total muscle work, and the cross-sectional knee extensor muscle area were assessed before and after exercise. Exercise was performed three times a week over an 8-week period at an intensity of approximately 20% of one-repetition maximum for straight leg raising and hip joint adduction and maximum force for abduction training. A significant increase in strength at 180°/s was noted after exercise in all subjects who exercised under vascular occlusion. Total muscle work increased significantly in the 50- and 150-pressure groups (P<0.05, P<0.01, respectively). There was no significant increase in cross-sectional knee extensor muscle area in any groups. In conclusion, resistance exercise with relatively low vascular occlusion pressure is potentially useful to increase muscle strength and endurance without discomfort.
x. Venous blood gas and metabolite response to low-intensity muscle contractions with external limb compression
The effect of low-intensity resistance exercise with external limb compression (100 [EC100] and 160 [EC160] mm Hg) on limb blood flow and venous blood gas-metabolite response was investigated and compared with that of high-intensity resistance exercise (no external compression). Unilateral elbow flexion muscle contractions were performed at 20% (75 repetitions, 4 sets, 30-second rest intervals) and 70% of 1-repetition maximum (1-RM; 3 sets, each set was until failure, 3-minute rest intervals). Precontraction brachial arterial blood flow (Doppler ultrasound) was reduced with EC100 or EC160 (56% and 39% of baseline value, respectively) compared with no external compression (control). At 20% 1-RM, brachial arterial blood flow increased after contractions performed with EC160 (190%), but not with the others. Decreases in venous oxygen partial pressure (PvO2) and venous oxygen saturation (SvO2) were greater during EC100 and EC160 than control (mean [SE]: PvO2, 28 [3] vs 26 [2] vs 33 [2] mm Hg; SvO2, 41% [5%] vs 34% [4%] vs 52% [5%], respectively). Changes in venous pH (pHv), venous carbon dioxide partial pressure (PvCO2), and venous lactate concentration ([L?]v) were greater with EC160 than EC100 and/or control (pHv, 7.19 [0.01] vs 7.25 [0.01] vs 7.27 [0.02]; PvCO2, 72 [3] vs 64 [2] vs 60 [3] mm Hg; [L?]v, 5.4 [0.6] vs 3.7 [0.4] vs 3.0 [0.4] mmol/L, respectively). Seventy percent 1-RM contractions resulted in greater changes in pHv (7.14 [0.02]), PvCO2 (91 [5] mm Hg), and [L?]v (7.0 [0.5] mmol/L) than EC100 and EC160, but PvO2 (30 [4] mm Hg) and SvO2 (40% [3%]) were similar. In conclusion, changes in pHv, PvCO2, and [L?]v, but not in PvO2 and SvO2, are sensitive to changes in relative, “internal” intensity of low-intensity muscle contractions caused by reduced blood flow (EC160) or high-intensity muscle contractions. Given the magnitude of the changes in pHv, PvCO2, and [L?]v, it appears plausible that they may be involved in stimulating the observed increase in muscle activation via group III and IV afferents.
x. The Use of Occlusion Training to Produce Muscle Hypertrophy
LOW-INTENSITY OCCLUSION (50-100 MM HG) TRAINING PROVIDES A UNIQUE BENEFICIAL TRAINING MODE FOR PROMOTING MUSCLE HYPERTROPHY. TRAINING AT INTENSITIES AS LOW AS 20% 1 REPETITION MAXIMUM WITH MODERATE VASCULAR OCCLUSION RESULTS IN MUSCLE HYPERTROPHY IN AS LITTLE AS 3 WEEKS. A TYPICAL EXERCISE PRESCRIPTION CALLS FOR 3 TO 5 SETS TO VOLITIONAL FATIGUE WITH SHORT REST PERIODS. THE METABOLIC BUILDUP CAUSES POSITIVE PHYSIOLOGIC REACTIONS, SPECIFICALLY A RISE IN GROWTH HORMONE THAT IS HIGHER THAN LEVELS FOUND WITH HIGHER INTENSITIES. OCCLUSION TRAINING IS APPLICABLE FOR THOSE WHO ARE UNABLE TO SUSTAIN HIGH LOADS DUE TO JOINT PAIN, POSTOPERATIVE PATIENTS, CARDIAC REHABILITATION, ATHLETES WHO ARE UNLOADING, AND ASTRONAUTS.
x. Effects of Handgrip Training With Venous Restriction on Brachial Artery Vasodilation
Previous studies have shown that resistance training with restricted venous blood flow (Kaatsu) results in significant strength gains and muscle hypertrophy. However, few studies have examined the concurrent vascular responses following restrictive venous blood flow training protocols.
Purpose: To examine the effects of 4 weeks of handgrip exercise training, with and without venous restriction, on handgrip strength and brachial artery flow mediated dilation (BAFMD).
Methods: Twelve participants (age=22+/-1yr; male = 5, female = 7), completed 4 weeks of bilateral handgrip exercise training (Duration: 20 min; Intensity: 60% of the MVC; Cadence: 15 grips*min-:1; Frequency: 3 sessions*week-1). During each session venous blood flow was restricted in one arm (Experimental arm = EXP) using a pneumatic cuff placed 4 cm proximal to the antecubital fossa, and inflated to 80 mmHg for the duration of each exercise session. The EXP and control (CON) arm were randomly selected. Handgrip strength was measured using a hydraulic hand dynamometer. Brachial diameters and blood velocity profiles were assessed, using Doppler ultrasonography, before and after 5 min of forearm occlusion (200 mmHg), prior to and at the end of 4 weeks exercise.
Results: Following exercise training, handgrip strength increased 8.32% (p=0.05) in the CON arm and 16.17% (p=0.05) in the EXP arm. BAFMD increased 24.19% (p=0.0001) in the CON arm, and decreased 30.36% (p=0.0001) in the EXP arm.
Conclusion: The data indicate handgrip training combined with venous restriction results in superior strength gains, but reduced BAFMD compared to the non-restricted arm.
x. Acute vascular occlusion in horses: effects on skeletal muscle size and blood flow
The purpose of this study was to demonstrate whether acute vascular occlusion was safe and if it would result in changes to limb muscle size in horses. Six healthy, unfit Standardbred mares were used. Horses (standing at rest) wore an occlusion cuff at the most proximal position of the left forelimb. The right forelimb was used as control. An occlusion pressure of 200 mmHg was set for 5 min followed by a 2 min recovery. Three sets of occlusions were given to each horse. Muscle thickness was measured using B-mode ultrasound. The circumference of the forelimb and first phalanx was measured using a flexible tape measure. Pulsed-wave Doppler was performed on the radialis artery with a 5–10 MHz mechanical transducer at baseline and at each occlusion. Peak flow velocity (PFV) and the flow velocity integral (FVI) were measured each time. Mid-forelimb, but not first phalanx, girth was increased (P<0.05) in the occluded but not in the control leg following occlusion. Extensor and flexor muscle thickness was increased (P<0.05) in the occluded but not in the control leg. There were no changes (P>0.05) in PFV or FVI at any measurement time point. Acute vascular occlusion may be a suitable and safe model for studying muscle hypertrophy in horses.
x. Increase in calf post-occlusive blood flow and strength following short-term resistance exercise training with blood flow restriction in young women
The response of calf muscle strength, resting (R bf) and post-occlusive (PObf) blood flow were investigated following 4 weeks resistance training with and without blood flow restriction in a matched leg design. Sixteen untrained females performed unilateral plantar-flexion low-load resistance training (LLRT) at either 25% (n = Cool or 50% (n = Cool one-repetition maximum (1 RM). One limb was trained with unrestricted blood flow whilst in the other limb blood flow was restricted with the use of a pressure applied cuff above the knee (110 mmHg). Regardless of the training load, peak PObf, measured using venous occlusion plethysmography increased when LLRT was performed with blood flow restriction compared to no change following LLRT with unrestricted blood flow. A significant increase (P < 0.05) in the area under the blood time–flow curve was also observed following LLRT with blood flow restriction when compared LLRT with unrestricted blood flow. No changes were observed in R bf between groups following training. Maximal dynamic strength (1 RM), maximal voluntary contraction and isokinetic strength at 0.52 and 1.05 rad s?1 also increased (P < 0.05) by a greater extent following resistance training with blood flow restriction. Moreover, 1 RM increased to a greater extent following training at 50% 1 RM compared to 25% 1 RM. These results suggest that 4 weeks LLRT with blood flow restriction provides a greater stimulus to increase peak PObf as well as strength parameters than LLRT with unrestricted blood flow.
x. Changes of Compound Muscle Action Potential after Low-Intensity Exercise with Transient Restriction of Blood Flow: a Randomized, Placebo-Controlled Trial
Abstract. [Purpose] The purpose of this study was to investigate the mechanism of muscular force improvement after low-intensity exercise with transient restriction of blood flow using compound muscle action potential (CMAP) analysis. [Subjects] Thirty healthy subjects in their 20s (mean age=21.73 years) were randomly assigned to an experimental group (EG) and a placebo control group (PG); each group had 15 subjects. [Methods] CMAP was analyzed by measuring terminal latency and amplitude using a motor nerve conduction velocity test. For Baseline 1, supramaximal electrical stimulation was applied to the median nerves of the EG and PG to obtain CMAP at the abductor pollicis brevis. For Baseline 2, the intensity of the electrical stimulation was decreased to a level at which the CMAP amplitude was about a third (1/3) of the CMAP amplitude obtained by supramaximal electrical stimulation. In the first test, CMAP was obtained under the same conditions as Baseline 2 after low-intensity thumb abduction exercises were performed at subjects' own pace for one minute. EG had blood flow restricted by a sphygmomanometer cuff, but PG did not. In the retest, CMAP was obtained under the same conditions as Baseline 2, one minute after the removal of the sphygmomanometer cuff immediately after the first test. [Results] PG did not show significant changes in CMAP, whereas EG showed a significant increase in CMAP amplitude, signifying that more muscle fibers were recruited. [Conclusion] This study found that low-intensity exercise with transient restriction of blood flow recruited more muscle fibers than low-intensity exercise without transient restriction of blood flow.
x. Growth hormone and muscle function responses to skeletal muscle ischemia
We examined the effects of ischemia (ISC) alone and with low-intensity exercise (ISC+EX) on growth hormone (GH) and muscle function responses. Nine men (22 ± 0.7 yr) completed 3 study days: an ISC day (thigh cuff inflated five times, 5 min on, 3 min off), an ISC+EX day [knee extension at 20% maximal voluntary contraction (MVC) with ISC], and a control day. MVCs and submaximal contraction tasks (15 and 30% MVC) were performed before and following the perturbations. Surface electromyogram signals were collected from thigh muscles and analyzed for median frequency and root mean square alterations. Blood samples were collected every 10 min (190 min total) and analyzed for GH concentrations. Peak GH concentrations and GH area under the curve were highest (P < 0.01) on the ISC+EX day (7.5 µg/l and 432 µg·l–1·min–1, respectively) compared with the ISC (0.9 µg/l and 76.4 µg·l–1·min–1), and CON (1.1 µg/l and 83.8 µg·l–1·min–1) days. A greater GH pulse amplitude, mass/pulse, and production rate were also observed on the ISC+EX day (P < 0.05). Following the intervention, force production decreased on the ISC and ISC+EX days by 16.1 and 55.8%, respectively, and did not return to baseline values within 5 min of recovery. During the submaximal contractions, median frequency shifted to lower frequencies for most of the muscles examined, and root mean square electromyogram was consistently elevated for ISC+EX day. In conclusion, ISC coupled with resistance exercise acutely increases GH levels and reduces MVC, whereas ISC alone decreases force capacity, without alterations in GH levels.
x. Changes In Tissue Oxygenation And Muscular Function In Response To Vascular Restriction: 1826: Board #176 May 27 2:00 PM - 3:30 PM
A single bout of low-intensity resistance exercise (20% 1-RM) combined with vascular restriction (i.e., KAATSU training) takes about 3-5 min to elicit a fatigue response. It has been reported that vascular restriction alone has been used to prevent atrophy, therefore, it would be important to determine how different pressures of blood flow restriction, applied for similar durations, can alter the metabolic demands of skeletal muscle and change muscle function.
PURPOSE: To examine the effects of altering vascular restriction pressure of the leg on percent voluntary activation (PVA) of the medial gastrocnemius (MG), tissue oxygenation of the calf muscles, and the electromyographic (EMG) and mechanomyographic (MMG) responses of MG.
METHODS: Thirteen young healthy males (Mean ± SD age = 24.6 ± 5.3 years; height = 175.7 ± 5.3 cm; weight = 77.7 ± 7.5 kg) performed one maximal isometric voluntary contraction (MVC) of the right plantar flexors at baseline. Then, following 2-min rest, six different pressures (40, 120, 160, 180, 200, 250 mmHg) were sequentially applied to restrict blood flow for 4-min with 2-min rest periods between trials with no pressure. At the end of each pressure setting, a MVC was performed. PVA, EMG and MMG responses were assessed during the twitch interpolation technique and tissue oxygenation was measured by near infrared spectroscopy. A repeated measures ANOVA was used to determine the main effects for trial with the level of significance set at 0.05.
RESULTS: The results showed that tissue oxygenation significantly decreased with increasing pressures (p<0.05, ranged from 81% to 46%). However, there were no significant changes in MVC torque, PVA, EMG amplitude, EMG mean power frequency (MPF), MMG amplitude, and MMG MPF.
CONCLUSIONS: Four minute periods of restricting blood flow to the lower limb with pressures up to 250 mmHg were not sufficient to induce a significant metabolic challenge that would cause changes in muscular function.
x. Venous Blood Changes with Low-Intensity Muscle Contractions and Blood Flow Restriction: 1989: Board #153 May 29 2:00 PM - 3:30 PM
Work output during repetitive low-intensity muscle contractions is presumably maintained by increased motor unit recruitment (increased EMG activity) during restricted blood flow. Interestingly, the increased muscle activation is associated with an increased oxygen uptake (Vo2); an unexpected finding given the same external work and reduced muscle blood flow.
PURPOSE: To investigate changes in venous blood metabolites and gases during repetitive muscle contractions with restricted blood flow.
METHODS: Six male volunteers performed 3 trials (separated by 1-week) of unilateral elbow flexion muscle contractions (20% of 1-RM; 30 repetitive contractions then 3 sets of 15 contractions, 30 sec rest between sets). Contractions were performed with unrestricted blood flow (C) or two levels of blood flow restriction using a KAATSU belt; a specially designed elastic cuff placed at the most proximal position of the upper arm and inflated to either 100 (K100) or 160 (K160) mmHg to restrict blood flow. Venous blood was collected prior to contractions and following the 30 repetitive contractions and the last set of 15 contractions; (an indwelling catheter inserted in the brachial vein below the cuff). Venous blood was analyzed using a blood gas analyzer (Instrumentation Laboratory, Japan).
RESULTS: Oxygen saturation decreased with contractions in all trials (P<0.05) with K160 (33% and 34%, respectively) being greater than K100 (41% and 42%, respectively) and both greater than C (67% and 56%, respectively). Changes in venous blood pH and PCO2 were greater in K160 than K100 and C. Venous PO2 decreased similarly in K160 and K100, significantly less than C. Hematocrit and [glucose] were similar in all trials while [lactate] was greater (P<0.05) in K160 (4.4 and 5.6 mmol/L, respectively) than K100 (3.2 and 3.6 mmol/L, respectively) and C (2.5 and 2.9 mmol/L, respectively).
CONCLUSION: The significant reduction in oxygen saturation supports the previously observed increase in VO2 during blood flow restriction. The basis for the greater lactate concentration is unknown; either increased production or reduced removal. These data appear to support the conclusion that energy supply is paradoxically increased during low-intensity muscle contractions with restricted blood flow, likely associated with increased muscle activation.
x. What phenomena do occur in blood flow-restricted muscle?
Oxygen is an essential molecule for all cellular activities including growth. Either excessive or deficient oxygen supply to cells induces the various responses of the cells. In the field of pathophysiology, effects of blood flow restriction on various organs have been studied for the past ?130 years. Subsequently, the roles of oxygen at subcellular level have been studied in vitro. Although a number of studies show that a low-intensity exercise (20?50% of one repetition maximum) with a moderate tourniquet restriction of blood flow results in increases in muscular strength and size, the mechanisms for this muscular adaptation remain unclear. In particular, it is uncertain whether the low-intensity exercise with blood flow restriction using a tourniquet causes the hypoxia or hyperoxia in the muscle, and then what signals leading to muscular hypertrophy are activated inside and/ or outside the cells. Also, it is not well understood what side effects occur in addition to conferring the benefits of strength gains. The review summarizes recent studies on the muscular adaptations to oxygen environment and discusses the mechanisms that may be involved in the resistance exercise with restricted blood flow.
x. Time under Tension and Blood Lactate Response during Four Different Resistance Training Methods
Mechanical stimuli have often been suggested to be the major determinant of resistance training adaptations; however, some studies suggested that metabolic changes also play an important role in the gains of muscle size and strength. Several resistance training methods (RTM) have been employed with the purpose of manipulating mechanical and metabolic stimuli; however, information about their physiological effects are scarce. The objective of this study was to compare the time under tension (TUT) and blood lactate responses among four different RTM reported in the literature. The four RTM were performed in a knee extension machine at 10 repetition maximum (RM) load by 12 recreationally trained young men. The RTM tested were: 10RM, super-slow (SL—subjects performed one 60-second repetition with 30 seconds for eccentric and 30 seconds for concentric phase), functional isometrics (FI—in each repetition, a five-second maximal isometric contraction was executed with the knees fully extended) and adapted vascular occlusion (VO—subjects performed a 20-second maximal isometric contraction with the knees fully extended and immediately proceeded to normal isoinertial lifts). According to the results, all RTM produced significant increases in blood lactate levels. However, blood lactate responses during FI (4.48±1.57 mM) and VO (4.23±1.66 mM) methods were higher than the SL method (3.41±1.14 mM). The TUT for SL (60 s), FI (56.33±6.46 s), and VO (53.08±4.76 s) methods were higher than TUT for 10RM (42.08±3.18 s). Additionally, TUT for the SL method was higher than TUT during the VO method. Therefore, the SL method may not be recommended if one wants to provide a high metabolic stimulus. The FI method appeared to be especially effective in promoting both type of stimuli.
x. Enhancement of cardiac autonomic nervous system activity by blood flow restriction in the human leg
The purpose of this study is to develop a unique method to enhance autonomic nervous system (ANS) activity by means of experimental leg occlusion. The effects of blood flow restriction on the activities of the ANS during rest were investigated using a power spectral analysis of heart rate variability. Two patterns of occlusion were randomly assigned to healthy subjects: pattern A, 10 min of 1.4 times of systolic blood pressure; pattern B, 5 min of mean blood pressure followed by 5 min of 1.4 times of systolic blood pressure. Electrocardiogram, blood pressure and cardiac output were continuously monitored during rest and occlusion. During occlusion, cardiac output and stroke volume showed significant decreases, due to modulation of autonomic nervous activity. After releasing from occlusion without blood pooling (A), the high frequency component of R-R interval variability representing vagal activity showed a significant increase (P<0.05). However, soon after releasing, the ECG QTc interval temporally prolonged (P<0.05) and recovered gradually. Further investigation is recommended to determine blood flow occlusion safety on the cardiac depolarization-repolarization process. In conclusion, the results suggest that blood flow restriction has potential to be a useful method to stimulate the activity of autonomic nervous system, and especially to enhance parasympathetic nervous system activity.
x. Plasticity of the Muscle Proteome to Exercise at Altitude
Flueck, Martin. Plasticity of the muscle proteome to exercise at altitude. High Alt. Med. Biol. 10: 183–193, 2009.—The ascent of humans to the summits of the highest peaks on Earth initiated a spurt of explorations into the physiological consequences of physical activity at altitude. The past three decades have demonstrated that the resetting of respiratory and cardiovascular control with chronic exposure to altitudes above 4000m is accompanied by important structural–functional adjustments of skeletal muscle. The fully altitude-adapted phenotype preserves energy charge at reduced aerobic capacity through the promotion of anaerobic substrate flux and tighter metabolic control, often at the expense of muscle mass. In seeming contrast, intense physical activity at moderate hypoxia (2500 to 4000m) modifies this response in both low and high altitude natives through metabolic compensation by elevating local aerobic capacity and possibly preventing muscle fiber atrophy. The combined use of classical morphometry and contemporary proteomic technology provides a highly resolved picture of the temporal control of hypoxia-induced muscular adaptations. The muscle proteome signature identifies mitochondrial autophagy and protein degradation as prime adaptive mechanisms to passive altitude exposure and ascent to extreme altitude. Protein measures also explain the lactate paradox by a sparing of glycolytic enzymes from general muscle wasting. Enhanced mitochondrial and angiogenic protein expression in human muscle with exercise up to 4000m is related to the reduction in intramuscular oxygen content below 1% (8torr), when the master regulator of hypoxia-dependent gene expression, HIF-1?, is stabilized. Accordingly, it is proposed here that the catabolic consequences of chronic hypoxia exposure reflect the insufficient activation of hypoxia-sensitive signaling and the suppression of energy-consuming protein translation.
x. Effects of low-intensity resistance exercise with slow movement and tonic force generation on muscular function in young men
We investigated the acute and long-term effects of low-intensity resistance exercise (knee extension) with slow movement and tonic force generation on muscular size and strength. This type of exercise was expected to enhance the intramuscular hypoxic environment that might be a factor for muscular hypertrophy. Twenty-four healthy young men without experience of regular exercise training were assigned into three groups (n = 8 for each) and performed the following resistance exercise regimens: low-intensity [~50% of one-repetition maximum (1RM)] with slow movement and tonic force generation (3 s for eccentric and concentric actions, 1-s pause, and no relaxing phase; LST); high-intensity (~80% 1RM) with normal speed (1 s for concentric and eccentric actions, 1 s for relaxing; HN); low-intensity with normal speed (same intensity as for LST and same speed as for HN; LN). In LST and HN, the mean repetition maximum was 8RM. In LN, both intensity and amount of work were matched with those for LST. Each exercise session consisting of three sets was performed three times a week for 12 wk. In LST and HN, exercise training caused significant (P < 0.05) increases in cross-sectional area determined with MRI and isometric strength (maximal voluntary contraction) of the knee extensors, whereas no significant changes were seen in LN. Electromyographic and near-infrared spectroscopic analyses showed that one bout of LST causes sustained muscular activity and the largest muscle deoxygenation among the three types of exercise. The results suggest that intramuscular oxygen environment is important for exercise-induced muscular hypertrophy.
x. Increase in maximal oxygen uptake following 2-week walk training with blood flow occlusion in athletes
Walk training with blood flow occlusion (OCC-walk) leads to muscle hypertrophy; however, cardiorespiratory endurance in response to OCC-walk is unknown. Ischemia enhances the adaptation to endurance training such as increased maximal oxygen uptake ($$ V{\text{O}}_{{ 2_{ \max } }} $$) and muscle glycogen content. Thus, we investigated the effects of an OCC-walk on cardiorespiratory endurance, anaerobic power, and muscle strength in elite athletes. College basketball players participated in walk training with (n = 7) and without (n = 5) blood flow occlusion. Five sets of a 3-min walk (4–6 km/h at 5% grade) and a 1-min rest between the walks were performed twice a day, 6 days a week for 2 weeks. Two-way ANOVA with repeated measures (groups × time) was utilized (P < 0.05). Interactions were found in $$ V{\text{O}}_{{ 2_{ \max } }} $$ (P = 0.011) and maximal minute ventilation (VEmax; P = 0.019). $$ V{\text{O}}_{{ 2_{ \max } }} $$ (11.6%) and VEmax (10.6%) were increased following the OCC-walk. For the cardiovascular adaptations of the OCC-walk, hemodynamic parameters such as stroke volume (SV) and heart rate (HR) at rest and during OCC-walk were compared between the first and the last OCC-walk sessions. Although no change in hemodynamics was found at rest, during the last OCC-walk session SV was increased in all five sets (21.4%) and HR was decreased in the third (12.3%) and fifth (15.0%) sets. With anaerobic power an interaction was found in anaerobic capacity (P = 0.038) but not in peak power. Anaerobic capacity (2.5%) was increased following the OCC-walk. No interaction was found in muscle strength. In conclusion, the 2-week OCC-walk significantly increases $$ V{\text{O}}_{{ 2_{ \max } }} $$ and VEmax in athletes. The OCC-walk training might be used in the rehabilitation for athletes who intend to maintain or improve endurance.
x. Delayed-onset muscle soreness induced by low-load blood flow-restricted exercise
Abstract We performed two experiments to describe the magnitude of delayed-onset muscle soreness (DOMS) associated with blood flow restriction (BFR) exercise and to determine the contribution of the concentric (CON) versus eccentric (ECC) actions of BFR exercise on DOMS. In experiment 1, nine subjects performed three sets of unilateral knee extension BFR exercise at 35% of maximal voluntary contraction (MVC) to failure with a thigh cuff inflated 30% above brachial systolic pressure. Subjects repeated the protocol with the contralateral limb without flow restriction. Resting soreness (0–10 scale) and algometry (pain–pressure threshold; PPT) were assessed before and 24, 48 and 96 h post-exercise. Additionally, MVC and vastus lateralis cross-sectional area (CSA) were measured as indices of exercise-induced muscle damage. At 24-h post-exercise, BFR exercise resulted in more soreness than exercise without BFR (2.8 ± 0.3 vs 1.7 ± 0.5) and greater reductions in PPT (15.2 ± 1.7 vs. 20 ± 2.3 N) and MVC (14.1 ± 2.5% decrease vs. 1.5 ± 4.5% decrease) (p ? 0.05). In experiment 2, 15 different subjects performed three sets of unilateral BFR exercise at 35% MVC with one limb performing only the CON action and the contralateral performing the ECC action. The aforementioned indices of DOMS were assessed before exercise and 24, 48 and 96 h post-exercise. At 24 h post-exercise, CON BFR exercise resulted in more resting soreness than ECC BFR exercise (3.0 ± 0.5 vs. 1.6 ± 0.4), and a greater decrease in MVC (9.8 ± 2.7% decrease vs. 3.4 ± 2.5% decrease) (p ? 0.05). These data suggest that knee extension BFR exercise induces mild DOMS and that BFR exercise elicits muscle damage under atypical conditions with low-tension concentric contractions.
x. Prevention of Disuse Muscular Weakness by Restriction of Blood Flow
Purpose: The aim of the present study was to compare the effects of periodic restriction of blood flow to lower extremities with those of isometric exercise on disuse muscular atrophy and weakness induced by immobilization and unloading.
Methods: The left ankle of each of 15 healthy males was immobilized for 2 wk using cast, and subjects were instructed to walk using crutches with non-weight bearing during this period. Subjects were divided into three groups: a restriction of blood flow (RBF) group (application of external compressive force of 200 mm Hg for 5 min followed by 3 min of rest, repeated five times in a single session, two sessions per day for 14 d); an isometric training (IMT) group (20 "exercises" of 5-s isometric contraction of the knee extensor, flexor, and ankle plantar flexor muscles followed by rest, twice a day, daily for 2 wk); and a control (CON) group (no intervention). We measured changes in muscle strength, thigh/leg circumferences, and serum growth hormone levels.
Results: Immobilization/unloading resulted in significant decreases in muscle strength of knee extensor and flexor muscles (P < 0.01 and < 0.05, respectively) and thigh and leg circumferences (P < 0.05, each) in the CON group, and significant decreases in muscle strength of the knee flexor muscles, ankle plantar flexor muscles, and leg circumference (P < 0.05) in the IMT group. RBF protected against these changes in muscle strength and thigh/leg circumference (P < 0.01 and < 0.05, respectively). No changes in serum growth hormone levels were noted.
Conclusion: Our results indicate that repetitive restriction of blood flow to the lower extremity prevents disuse muscular weakness.
x. Comparison of hormone responses following light resistance exercise with partial vascular occlusion and moderately difficult resistance exercise without occlusion
Previous studies of contracting muscle with low loading and partial vascular occlusion demonstrated hypertrophy and strength adaptations similar to and exceeding those observed with traditional moderate to high resistance (Shinohara M, Kouzaki M, Yoshihisa T, and Fukunaga T. Eur J Physiol 77: 189–191, 1998; Takarada Y, Takazawa H, Sato Y, Takebayashi S, Tanaka Y, and Ishii N. J Appl Physiol 88: 2097–2106, 2000; Takarada Y, Sato Y, and Ishii N. Eur J Physiol 86: 308–314, 2002). The purpose of the study was to determine the anabolic and catabolic hormone responses to light resistance exercise combined with partial vascular occlusion. Three experimental conditions of light resistance with partial occlusion (LRO), moderate resistance with no occlusion (MR), and partial occlusion without exercise (OO) were performed by eight healthy subjects [mean 21 yr (SD 1.Cool]. Three sets of single-arm biceps curls and single-leg calf presses were completed to failure with 1-min interset rest periods. Workloads of 30 and 70% one repetition maximum for each exercise were lifted for the LRO and MR trials, respectively. Blood samples were taken preexercise, postexercise, and 15 min postexercise for each experimental condition. Lactate increased significantly in the LRO and MR trials and was not significantly different from each other at any time point. Growth hormone (GH) increased significantly by fourfold from pre- to postexercise in the LRO session but did not change significantly during this time period in the MR and OO trials (8.3 ± 2.3 vs. 2.1 ± 1.2 and 2.6 ± 0.94 µg/l; respectively, P < 0.05). There were no changes in resting total testosterone [T; mean 15.7 ± 1.6 (SE) nmol/l], free testosterone (FT; 54.1 ± 4.5 pmol/l), or cortisol (267.6 ± 22 nmol/l) across all trials and times. In conclusion, with similar lactate responses, light exercise combined with partial vascular occlusion elicits a greater GH response than moderate exercise without occlusion but does not affect T, FT, or cortisol.
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Muscle size and strength are increased following walk training with restricted venous blood flow from the leg muscle, Kaatsu-walk training
Takashi Abe,1 Charles F. Kearns,1 and Yoshiaki Sato2
1Department of Exercise and Sport Science, Tokyo Metropolitan University, and 2Department of Ischemic Circulatory Physiology, University of Tokyo, Tokyo, Japan
Submitted 3 October 2005 ; accepted in final form 29 November 2005
Previous studies have shown that low-intensity resistance training with restricted muscular venous blood flow (Kaatsu) causes muscle hypertrophy and strength gain. To investigate the effects of daily physical activity combined with Kaatsu, we examined the acute and chronic effects of walk training with and without Kaatsu on MRI-measured muscle size and maximum dynamic (one repetition maximum) and isometric strength, along with blood hormonal parameters. Nine men performed Kaatsu-walk training, and nine men performed walk training alone (control-walk). Training was conducted two times a day, 6 days/wk, for 3 wk using five sets of 2-min bouts (treadmill speed at 50 m/min), with a 1-min rest between bouts. Mean oxygen uptake during Kaatsu-walk and control-walk exercise was 19.5 (SD 3.6) and 17.2 % (SD 3.1) of treadmill-determined maximum oxygen uptake, respectively. Serum growth hormone was elevated (P < 0.01) after acute Kaatsu-walk exercise but not in control-walk exercise. MRI-measured thigh muscle cross-sectional area and muscle volume increased by 4–7%, and one repetition maximum and maximum isometric strength increased by 8–10% in the Kaatsu-walk group. There was no change in muscle size and dynamic and isometric strength in the control-walk group. Indicators of muscle damage (creatine kinase and myoglobin) and resting anabolic hormones did not change in both groups. The results suggest that the combination of leg muscle blood flow restriction with slow-walk training induces muscle hypertrophy and strength gain, despite the minimal level of exercise intensity. Kaatsu-walk training may be a potentially useful method for promoting muscle hypertrophy, covering a wide range of the population, including the frail and elderly.
Skeletal muscle size and circulating IGF-1 are increased after two weeks of twice daily “KAATSU” resistance training
T. Abe1), T. Yasuda1), T. Midorikawa1), Y. Sato2), C. F. Kearns3), K. Inoue4), K. Koizumi5) and N. Ishii6)
1) Department of Exercise and Sport Science, Tokyo Metropolitan University
2) Department of Ischemic Circulatory Physiology, The University of Tokyo
3) Cardiovascular/Endocrine Biology, Schering-Plough Research Institute
4) Orthopedic Medical Clinic
5) Department of Radiology, Tokyo Medical Uiversity Hachioji Medical Center
6) Department of Life Science, University of Tokyo
Abstract
This study investigated the effects of twice daily sessions of low-intensity resistance training (LIT, 20% of 1-RM) with restriction of muscular venous blood flow (namely “LIT-Kaatsu” training) for two weeks on skeletal muscle size and circulating insulin-like growth factor-1 (IGF-1). Nine young men performed LIT-Kaatsu and seven men performed LIT alone. Training was conducted two times / day, six days / week for 2 weeks using 3 sets of two dynamic exercises (squat and leg curl). Muscle cross-sectional area (CSA) and volume were measured by magnetic resonance imaging at baseline and 3 days after the last training session (post-testing). Mid-thigh muscle-bone CSA was calculated from thigh girth and adipose tissue thickness, which were measured every morning prior to the training session. Serum IGF-1 concentration was measured at baseline, mid-point of the training and post-testing. Increases in squat (17%) and leg curl (23%) one-RM strength in the LIT-Kaatsu were higher (p<0.05) than those of the LIT (9% and 2%). There was a gradual increase in circulating IGF-1 and muscle-bone CSA (both p<0.01) in the LIT-Kaatsu, but not in the LIT. Increases in quadriceps, biceps femoris and gluteus maximus muscle volume were, respectively, 7.7%, 10.1% and 9.1% for LIT-Kaatsu (p<0.01) and 1.4%, 1.9% and -0.6% for LIT (p>0.05). There was no difference (p>0.05) in relative strength (1-RM / muscle CSA) between baseline and post-testing in both groups. We concluded that skeletal muscle hypertrophy and strength gain occurred after two weeks of twice daily LIT-Kaatsu training.
PRINT ISSN : 1349-4562
International Journal of KAATSU Training Research
Vol. 1 (2005) , No. 1 pp.1-5
[PDF (136K)] [References]
The history and future of KAATSU Training
Y. Sato1)
1) Department of Ischemic Circulatory Physiology, The University of Tokyo
Abstract
KAATSU training involves the restriction of blood flow to exercising muscle and is the culmination of nearly 40 years of experimentation with the singular purpose of increasing muscle mass. KAATSU Training consists of performing low-intensity resistance training while a relatively light and flexible cuff is placed on the proximal part of one's lower or upper limbs, which provides appropriate superficial pressure. KAATSU Training should not be confused with training under ischemic conditions which has previously been reported (Sundberg, 1994). KAATSU Training does not induce ischemia within skeletal muscle, but rather promotes a state of blood pooling in the capillaries within the limb musculature. Applied basic and clinical research conducted over the past 10 years has demonstrated that KAATSU Training not only improves muscle mass and strength in healthy volunteers, but also benefits patients with cardiovascular and orthopedic conditions.
International Journal of KAATSU Training Research
Vol. 1 (2005) , No. 2 pp.65-70
[PDF (490K)] [References]
Muscle fiber cross-sectional area is increased after two weeks of twice daily KAATSU-resistance training
T. Yasuda1), T. Abe1), Y. Sato2), T. Midorikawa1), C. F. Kearns1), K. Inoue3), T. Ryushi1) and N. Ishii4)
1) Department of Exercise and Sport Science, Tokyo Metropolitan University
2) Department of Ischemic Circulatory Physiology, Kaatsu Training, University of Tokyo
3) Inoue Orthopedic Medical Clinic
4) Department of Life Science, The University of Tokyo
Abstract
The purpose of this study was to examine the effect of low-intensity (20% of 1-RM) resistance training (LIT) combined with restriction of muscular venous blood flow (KAATSU) on muscle fiber size using a biopsy sample. Three young men performed LIT-KAATSU (restriction pressure 160-240 mmHg), and two young men performed LIT alone. Training was conducted twice daily for 2 weeks using 3 sets of two dynamic lower body exercises. Quadriceps muscle CSA was measured by magnetic resonance imaging at midpoint of the thigh. Muscle biopsies were obtained from the vastus lateralis (VL) muscle using a needle biopsy. Mean relative change in 1-RM squat strength was 14% in the LIT-KAATSU and 9% in the LIT after two weeks of the training. Mean changes in quadriceps muscle CSA was 7.8% for LIT-KAATSU and 1.8% for LIT. Changes in muscle fiber CSA was 5.9% for type-I and 27.6% (p<0.05) for type-II in the LIT-KAATSU, and -2.1% and 0.5%, respectively, in the LIT. Mean fiber CSA changed 17.0% in the LIT-KAATSU, but not in LIT (-0.4%). We concluded that skeletal muscle and fiber hypertrophy, especially type-II fiber, occur after high frequency KAATSU training.
Muscle oxygenation and plasma growth hormone concentration during and after resistance exercise: Comparison between “KAATSU” and other types of regimen
M. Tanimoto1), H. Madarame1) and N. Ishii1)
1) Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo
Abstract
We investigated the acute effects of “Kaatsu” resistance exercise and other types of exercise on muscle oxygenation and plasma growth hormone. Six young male bodybuilders performed leg extension exercise according to four exercise regimens: low-intensity [?30% of one repetition maximum (1RM)] exercise with moderate occlusion (LO-Kaatsu), low-intensity (?50% 1RM) exercise with slow movement and tonic force generation (3 s for lowering and 3 s for lifting actions, 1-s pause, and no relaxing phase; LST), low-intensity (same as LST) isometric exercise at 45° knee angle (ISO), and high-intensity (?80% 1RM) exercise with normal movement speed (HN), commonly used for gaining muscular size and strength. The muscle oxygenation level measured with near-infrared continuous-wave spectroscopy (NIRcws) showed the largest changes during and after LO-Kaatsu among all regimens. The minimum oxygenation level during LO-Kaatsu was the lowest among the four exercise regimens. On the other hand, the increases in muscle oxygenation after LO-Kaatsu were the largest among the four regimens. Plasma GH and blood lactate concentrations after LO-Kaatsu, LST and HN were significantly (P < 0.05) higher than those after ISO, but there were no significant differences among those after LO-Kaatsu, LST and HN. The results indicate that “Kaatsu” resistance exercise causes marked changes in muscle oxygenation level and circulating growth hormone, both of which may be related to muscular hypertrophy.
[PDF (827K)] [References]
Hemodynamic and autonomic nervous responses to the restriction of femoral blood flow by KAATSU
H. Iida1), H. Takano2), K. Meguro2), K. Asada2), H. Oonuma1), T. Morita2), M. Kurano1), F. Sakagami3), K. Uno2), K. Hirose3)5), T. Nagata4), K. Takenaka2), J. Suzuki2), Y. Hirata2), T. Furuichi, F. Eto3), R. Nagai2), Y. Sato1) and T. Nakajima1)
1) Department of Ischemic Circulatory Physiology, University of Tokyo
2) Department of Cardiovascular Medicine, University of Tokyo
3) Department of Rehabilitation, Faculty of Medicine, University of Tokyo
4) Department of Respiratory Medicine, University of Tokyo
5) Department of Rehabilitation, Dokkyo University, School of Medicine
Abstract
KAATSU training is a novel method for strength training to induce muscle strength and hypertrophy. The purpose of the present study was to investigate the hemodynamic and autonomic nervous responses to the restriction of femoral blood flow by KAATSU. Ultrasonography, echocardiography and impedance cardiography were performed in ten healthy male volunteers aged 34 ± 1.5 before (pre), during and after (post) pressurization on both legs with KAATSU belts placed around proximal portion of both legs. The parameters measured were as follows; the superficial femoral arterial blood flow, left ventricular end-diastolic/systolic dimension (LVDd/LVDs), cardiac output (CO), stroke volume (SV), diameter of inferior vena cava (IVC), heart rate (HR), mean blood pressure (mBP), total peripheral resistance (TPR) and heart rate variability (HRV). The pressurization on both legs with KAATSU suppressed venous blood flow, and markedly induced pooling of blood into the legs with pressure-dependent reduction of femoral arterial blood flow. The application of 200 mmHg KAATSU decreased femoral arterial blood flow, LVDd, CO, SV and IVC significantly. HR tended to increase, and TPR increased significantly, but mBP did not change significantly. In addition, high frequency (HFRR), a marker of parasympathetic activity, decreased during KAATSU, while LFRR/HFRR, a quantitative marker of sympathetic autonomic nervous activity, increased significantly. These results indicate that the application of KAATSU on both legs induces venous pooling in the legs, and then inhibits venous return. The reduction of venous return causes a decrease of IVC diameter, cardiac size and stroke volume with an increase in TPR and LFRR/HFRR. Thus, the KAATSU training appears to become a useful method for potential countermeasure like lower body negative pressure (LBNP) against orthostatic intolerance for long-term bed rest or space flight as well as strength training to induce muscle strength and hypertrophy.
Hemodynamic and neurohumoral responses to the restriction of femoral blood flow by KAATSU in healthy subjects
Journal European Journal of Applied Physiology
Publisher Springer Berlin / Heidelberg
ISSN 1439-6319 (Print) 1439-6327 (Online)
Issue Volume 100, Number 3 / June, 2007
Category Original Article
DOI 10.1007/s00421-007-0430-y
Pages 275-285
Subject Collection Biomedical and Life Sciences
SpringerLink Date Wednesday, March 07, 2007
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Original Article
Hemodynamic and neurohumoral responses to the restriction of femoral blood flow by KAATSU in healthy subjects
Haruko Iida1, Miwa Kurano1, Haruhito Takano1, Nami Kubota1, Toshihiro Morita2, Kentaro Meguro2, Yoshiaki Sato1, Takashi Abe3, Yoshihisa Yamazaki4, Kansei Uno5, Katsu Takenaka2, Ken Hirose6 and Toshiaki Nakajima1 Contact Information
(1) Department of Ischemic Circulatory Physiology, KAATSU Training, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
(2) Department of Cardiovascular Medicine, The University of Tokyo, Tokyo, Japan
(3) Department of Human and Engineered Environmental Studies, Graduate School of Frontier Science, The University of Tokyo, Chiba, Japan
(4) Japan Manned Space Systems Corporation, Ibaraki, Japan
(5) Department of Computational Diagnostic Radiology and Preventive Medicine, The University of Tokyo, Tokyo, Japan
(6) Department of Rehabilitation Medicine, The University of Tokyo, Tokyo, Japan
Accepted: 14 February 2007 Published online: 7 March 2007
Abstract The application of an orthostatic stress such as lower body negative pressure (LBNP) has been proposed to minimize the effects of weightlessness on the cardiovascular system and subsequently to reduce the cardiovascular deconditioning. The KAATSU training is a novel method to induce muscle strength and hypertrophy with blood pooling in capacitance vessels by restricting venous return. Here, we studied the hemodynamic, autonomic nervous and hormonal responses to the restriction of femoral blood flow by KAATSU in healthy male subjects, using the ultrasonography and impedance cardiography. The pressurization on both thighs induced pooling of blood into the legs with pressure-dependent reduction of femoral arterial blood flow. The application of 200 mmHg KAATSU significantly decreased left ventricular diastolic dimension (LVDd), cardiac output (CO) and diameter of inferior vena cava (IVC). Similarly, 200 mmHg KAATSU also decreased stroke volume (SV), which was almost equal to the value in standing. Heart rate (HR) and total peripheral resistance (TPR) increased in a similar manner to standing with slight change of mean blood pressure (mBP). High-frequency power (HFRR) decreased during both 200 mmHg KAATSU and standing, while low-frequency/high-frequency power (LFRR/HFRR) increased significantly. During KAATSU and standing, the concentration of noradrenaline (NA) and vasopressin (ADH) and plasma renin activity (PRA) increased. These results indicate that KAATSU in supine subjects reproduces the effects of standing on HR, SV, TPR, etc., thus stimulating an orthostatic stimulus. And, KAATSU training appears to be a useful method for potential countermeasure like LBNP against orthostatic intolerance after spaceflight.
PRINT ISSN : 1349-4562
International Journal of KAATSU Training Research
Vol. 1 (2005) , No. 1 pp.13-18
[PDF (123K)] [References]
Effects of low-intensity “KAATSU” resistance exercise on hemodynamic and growth hormone responses
H. Takano1), T. Morita1), H. Iida1), M. Kato1), K. Uno1), K. Hirose2)4), A. Matsumoto1), K. Takenaka1), Y. Hirata1), T. Furuichi4), F. Eto2), R. Nagai1), Y. Sato3) and T. Nakajima1)3)
1) Department of Cardiovascular Medicine, University of Tokyo
2) Department of Rehabilitation, Faculty of Medicine, University of Tokyo
3) Department of Ischemic Circulatory Physiology, Kaatsu Training, University of Tokyo
4) Department of Rehabilitation, Dokkyo University School of Medicine
Abstract
Growth hormone (GH) is secreted in a pulsatile fashion during exercise, which promotes skeletal muscle growth and muscle strength. We compared the effects of different types of short-term low-intensity resistance exercise (STLIRE) on the hemodynamic and GH responses of men aged 20 to 45 years. Eleven untrained men performed 30 repetitions for 2 to 4 sets (mean 61 ± 7 repetitions) until fatigue for bilateral leg extension-flexion exercise (20% of 1 RM -Proteus Multi Exercise Machine) under the conditions of reduced muscle blood flow by applied pressure at the proximal ends of both legs by a specially-designed belt (Kaatsu Training). In the controlled exercise condition, without Kaatsu (n=9), subjects again performed the same exercise protocol as described above. Finally, a group of 5 men performed 3 sets of 10 repetitions using the Power Rehabilitation machine. Hemodynamic parameters were measured by using the impedance cardiography. Serum concentrations of GH, noradrenaline (NOR), and lactate were also measured. STLIRE with Kaatsu significantly increased GH, compared to STLIRE without Kaatsu. Maximal heart rate (HR) and blood pressure (BP) in STLIRE with Kaatsu were higher when compared to the control condition, however, stroke volume (SV) was lower compared to the controlled condition due to a decreased venous return induced by Kaatsu training. Total peripheral resistance (TPR) did not change significantly. The increase in NOR and lactate in STLIRE with Kaatsu was also significantly higher than without Kaatsu. These results suggest that “Kaatsu” leg resistance exercise caused a significant exercise-induced GH response even in STLIRE, with a reduction of cardiac preload during exercise. The results of the study indicate that Kaatsu training may become a unique method for rehabilitation in patients with cardiac diseases or low physical fitness.
Acute growth hormone response to low-intensity KAATSU resistance exercise: Comparison between arm and leg
Y. Sato1), A. Yoshitomi2) and T. Abe2)
1) Department of Ischmic Circulatory Physiology, The University of Tokyo
2) Department of Exercise and Sport Science, Tokyo Metropolitan University
Abstract
Exercise is a potent stimulus to GH secretion. However it is unclear if exercise-induced GH release differs between different muscle groups, i.e., arm and leg exercise, when performed at equivalent exercise intensity. The purpose of this study was to compare the GH responses to an acute resistance exercise, combined with restriction of muscular venous blood flow (KAATSU), in muscle groups of the arm and leg. Five young male subjects performed two types of exercise tests, arm and leg exercise, on separate days. The intensity of exercise was 20% of 1-RM, which was measured at least 1 week before the experiment. The external restriction pressure during the KAATSU exercise was selected 50% higher than each measured-arm and estimated-leg systolic blood pressure. Venous blood samples were obtained prior to the start of exercise, immediately post exercise, and 15- and 60-min after exercise, and blood lactate (LA), growth hormone (GH), noradrenaline (NA), hematocrit, albumin and Na/K concentrations were measured. Significant elevations were apparent immediately post and 15-min after exercise for LA and at immediately post, 15- and 60-min after exercise for GH in both arm and leg exercise. Significant elevation was also observed after exercise for NA in both arm and leg, but leg exercise resulted in a greater increase in NA than arm at immediately post exercise. Change in plasma volume after exercise was not different between two exercises. These results suggest that GH secretory responses to exercise may be similar between the arm and leg when performed at equivalent exercise intensity and restriction stimulus.
KAATSU-walk training increases serum bone-specific alkaline phosphatase in young men
M. D. Beekley1), Y. Sato2) and T. Abe3)
1) Department of Physical Education, United States Military Academy
2) Department of Ischemic Circulatory Physiology, Kaatsu Training, The University of Tokyo
3) Department of Exercise and Sport Science, Tokyo Metropolitan University
Abstract
Previous research has shown that high intensity resistance training causes increases in bone density and increases in serum measures of bone turnover like bone-specific alkaline phosphatase (BAP). Medium intensity or low intensity training (like walking) does not result in these changes. However, low intensity training with blood flow restriction (KAATSU) has shown promise in bone and muscle rehabilitation settings. We hypothesized that there would be increases in serum BAP following low intensity KAATSU walk training. Healthy men walked on a treadmill twice per day (at least 4 hours between sessions) for 3 weeks with (KAATSU; n=9) or without (Control; n=9) blood flow occlusion pressure belts on their thighs. After three weeks of training, the KAATSU group experienced significant increases in MRI-measured muscle CSA (P<0.01), 1-RM muscle strength (P<0.01), and serum BAP levels (P<0.05). Percent change in BAP was 10.8% for the KAATSU-walk and 0.3% for the Control-walk. There was no significant change in serum IGF-1 for either group. We conclude that 3 weeks KAATSU walk training increases BAP, a serum marker of bone turnover.
Electromyographic responses of arm and chest muscle during bench press exercise with and without KAATSU
T. Yasuda1), T. Fujita1), Y. Miyagi2), Y. Kubota2), Y. Sato3)5), T. Nakajima3), M.G. Bemben4) and T. Abe1)5)
1) Department of Exercise and Sport Science, Tokyo Metropolitan University
2) BodybyVital Research Laboratory
3) Department of Ischmic Circulatory Physiology, The University of Tokyo
4) Department of Health and Exercise Sciences, University of Oklahoma
5) Graduate School of Frontier Sciences, The University of Tokyo
(Accepted March 25, 2006)
Abstract
The purpose of this study was to compare the EMG activity of blood flow restricted (limb) and nonrestricted (trunk) muscles during multi-joint exercise with and without KAATSU. Twelve (6 women and 6 men) healthy college students [means (SD) age: 24.1 (3.5) yrs] performed 4 sets (30, 15, 15, and 15 reps) of flat bench press exercise (30% of a predetermined one repetition maximum, 1-RM) during two different conditions [with KAATSU and without KAATSU (Control)]. In the KAATSU condition, a specially designed elastic cuff belt (30 mm wide) was placed at the most proximal position of the upper arm and inflated to a pressure of 100% of individual's resting systolic blood pressure. Surface EMG was recorded from the muscle belly of the triceps brachii (TB) and pectoralis major (PM) muscles, and mean integrated EMG (iEMG) was analyzed. During 4 sets of the exercise, gradual increases in iEMG were observed in both TB and PM muscles for the KAATSU condition. The magnitude of the increases in iEMG in the TB and PM muscles were higher (P<0.05) with KAATSU compared to the Control condition. In the first set, the mean exercise intensity from normalized iEMG was approximately 40% of 1-RM in both Control and KAATSU conditions. However, the mean exercise intensity of both muscles were 60-70% of 1-RM for the KAATSU condition and only about 50% of 1-RM for the Control condition, respectively, during the fourth set. We concluded that increases in iEMG in the trunk muscle during KAATSU might be an important factor for KAATSU training-induced trunk muscle hypertrophy.
Eight days KAATSU-resistance training improved sprint but not jump performance in collegiate male track and field athletes
T. Abe1), K. Kawamoto2), T. Yasuda1), C. F. Kearns3), T. Midorikawa1) and Y. Sato4)
1) Department of Exercise and Sport Science, Tokyo Metropolitan University
2) Department of Sports Science, Fukushima University
3) Cardiovascular/Endocrine Biology, Schering-Plough Research Institute
4) Department of Ischemic Circulatory Physiology, The University of Tokyo
Abstract
The purpose of this study was to investigate the effects of short-term KAATSU-resistance training on skeletal muscle size and sprint/jump performance in college athletes. Fifteen male track and field college athletes were randomly divided into two groups: KAATSU (resistive exercise combined with blood flow restriction, n=9) and control (n=6) groups. The KAATSU group trained twice daily with squat and leg curl exercises (20% of 1-RM, 3 sets of 15 repetitions) for 8 consecutive days while both KAATSU and control groups participated in the regular sprint/jump training sessions. Maximal strength, muscle-bone CSA, mid-thigh muscle thickness (MTH), and sprint/jump performance were measured before and after the 8 days of training. The muscle-bone CSA increased 4.5% (p<0.01) in the KAATSU group but decreased 1% (p>0.05) in the control group. Quadriceps and hamstrings MTH increased (p<0.01) by 5.9% and 4.5%, respectively, in the KAATSU group but did not change in the control group. Leg press strength increased (9.6%, p<0.01) in the KAATSU group but not (4.8%, p>0.05) in the control group. Overall 30-m dash times improved (p<0.05) in the KAATSU-training group, with significant improvements (p<0.01) occurring during the initial acceleration phase (0-10m) but not in the other phases (10-20m and 20-30m). None of the jumping performances improved (p>0.05) for either the KAATSU or control groups. These data indicated that eight days of KAATSU-training improved sprint but not jump performance in collegiate male track and field athletes.
Day-to-day change in muscle strength and MRI-measured skeletal muscle size during 7 days KAATSU resistance training: A case study
T. Abe1), M.D. Beekley2), S. Hinata3), K. Koizumi3) and Y. Sato4)
1) Department of Exercise and Sport Science, Tokyo Metropolitan University
2) United States Military Academy
3) Department of Radiology, Tokyo Medical University Hachioji Medical Center
4) Department of Ischmic Circulatory Physiology, The University of Tokyo
Abstract
The purpose of this study was to examine the daily skeletal muscle hypertrophic and strength responses to one week of twice daily KAATSU training, and follow indicators of muscle damage and inflammation on a day-to-day basis, for one subject. KAATSU training resulted in a 3.1% increase in muscle-bone CSA after 7 days of training. Both MRI-measured maximum quadriceps muscle cross-sectional area (Q-CSA max) and muscle volume can be seen increasing after the first day of KAATSU training, and continuously increasing for the rest of the training period. Following 7 days KAATSU resistance training, the increases in Q-CSA max and muscle volume were 3.5% and 4.8%, respectively. Relative strength (isometric knee extension strength per unit Q-CSA max) was increased after training (before, 3.60 Nm/cm2; after, 4.09 Nm/cm2). There were very modest increases in CK and myoglobin after a single bout of KAATSU exercise in the first day of the training, but the values were return towards normal at 2 days after the training. IL-6 remained unchanged throughout the training period. In conclusion, our subject gained absolute strength and increased muscle size after only one week of low intensity KAATSU resistance training. Indicators of muscle damage and inflammation were not elevated by this training. KAATSU training appears to be a safe and effective method to rapidly induce skeletal muscle strength and hypertrophy.
Use and safety of KAATSU training:Results of a national survey
T. Nakajima1), M. Kurano1), H. Iida1), H. Takano2), H. Oonuma1), T. Morita2), K. Meguro2), Y. Sato1), T. Nagata3) and KAATSU Training Group
1) Department of Ischemic Circulatory Physiology, KAATSU Training, University of Tokyo
2) Department of Cardiovascular Medicine, University of Tokyo
3) Department of Respiratory Medicine, University of Tokyo
(Accepted January 25, 2006)
Abstract
KAATSU training is a novel training, which is performed under conditions of restricted blood flow. It can induce a variety of beneficial effects such as increased muscle strength, and it has been adopted by a number of facilities in recent times. The purpose of the present study is to know the present state of KAATSU training in Japan and examine the incidence of adverse events in the field. The data were obtained from KAATSU leaders or instructors in a total of 105 out of 195 facilities where KAATSU training has been adopted. Based on survey results, 12,642 persons have received KAATSU training (male 45.4%, female 54.6%). KAATSU training has been applied to all generations of people including the young (<20 years old) and the elderly (>80 years old). The most popular purpose of KAATSU training is to strengthen muscle in athletes and to promote the health of subjects, including the elderly. It has been also applied to various kinds of physical conditions, cerebrovascular diseases, orthopedic diseases, obesity, cardiac diseases, neuromuscular diseases, diabetes, hypertension and respiratory diseases. In KAATSU training, various types of exercise modalities (physical exercise, walking, cycling, and weight training) are used. Most facilities have used 5-30 min KAATSU training each time, and performed it 1-3 times a week. Approximately 80% of the facilities are satisfied with the results of KAATSU training with only small numbers of complications reported. The incidence of side effects was as follows; venous thrombus (0.055%), pulmonary embolism (0.008%) and rhabdomyolysis (0.008%). These results indicate that the KAATSU training is a safe and promising method for training athletes and healthy persons, and can also be applied to persons with various physical conditions.
Equine Vet J Suppl. 2006 Aug;(36):345-8.
Muscle, tendon, and somatotropin responses to the restriction of muscle blood flow induced by KAATSU-walk training.
Abe T, Kearns CF, Manso Filho HC, Sato Y, McKeever KH.
Department of Exercise and Sport Science, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachioji, Tokyo 192-0397, Japan.
OBJECTIVE: The efficacy of KAATSU training has been demonstrated in human athletes, both as a therapeutic method as well as a training aid. The purpose of this study was to investigate the effects of slow walk training combined with restriction of muscle blood flow (KAATSU) on muscle and tendon size. METHODS: Six healthy, unfit Standardbred mares performed walking (240 m/min for 10 min and then 5 min recovery) with KAATSU, and 6 mares performed walking without KAATSU. A specially designed elastic cuff1 was placed at the most proximal position of the forelegs and inflated to a pressure of 200-230 mmHg throughout the walking and recovery sessions. The training was conducted once a day, 6 days/week for 2 weeks. Skeletal muscle thickness and tendon thickness were measured using B-mode ultrasound at baseline and after 2 weeks of training. Venous blood samples were obtained before the first acute exercise and 5, 15 and 60 min afterwards. Serum somatotropin concentration was determined using a commercially available equine-specific ELISA kit. RESULTS: The acute increase in plasma somatotropin was 40% greater (P<0.05) in the KAATSU-walk group than in the Control-walk group 5 min after exercise and remained elevated (P<0.05) at 15 and 60 min post exercise compared with the Control-walk group. After 2 weeks of training, muscle thickness increased (P<0.05) 3.5% in the KAATSU-walk group but did not change in the Control-walk group (0.7%). Tendon thickness did not change (P>0.05) in either group. CONCLUSIONS: These data demonstrate that KAATSU training can induce muscle hypertrophy in horses and suggest that KAATSU training may provide significant therapeutic/ rehabilitative value in horses, as has been shown in man.
Kaatsu training for patella tendinitis patient
S. Sata1)
1) Sata Orthopedic Hospital
Abstract
Low-intensity Kaatsu resistance training performed by patients with moderate vascular occlusion is known to cause skeletal muscle hypertrophy over a short term. In our patients who used such training as a part of their rehabilitation, we have seen the same results, as well as a quenching analgesic effect. Herein, we report the effect of Kaatsu resistance training in a patient with patella tendinitis. The patient was a 17-year-old male who played basketball and came to us with intense pain at the lower edge of the patella in the right knee and was confirmed by an MRI image which showed a high intensity signal in the area of the patella tendon. Initially, we gave a dose of antiphlogistic analgetic, a steroid injection, and prescribed hospitalization for 1 month. Kaatsu resistance training was also recommended in an attempt to prevent muscle atrophy. The vascular occlusion point for the Kaatsu training cuff was the proximal end of the right limb, which had an occlusion pressure ranging from 160-180 mmHg. The exercise components that were used in combination with the Kaatsu training program were SLR, hip abduction, hip adduction, calf raise, toe raise, squat, crunch, back extension, and shooting. The exercise protocol was performed at about 30% of 1RM, with 3 sets of 15 repetitions, 5 to 6 times per week, for 3 weeks. T2 weighted MRI images (axial and sagittal) of the right patella tendon prior to beginning Kaatsu training showed high intensity signals, however, after 3 weeks of Kaatsu training, the signal intensity was reduced and the thigh circumference was increased by 7 mm and 2 mm for the right and left sides, respectively. Further, there was no evidence of muscle atrophy. The present patient was then treated with appropriate anti-inflammatory drugs and 1-month of hospitalization. During that time it was possible to completely relieve the inflammation and avoid muscle atrophy with Kaatsu training, and the patient quickly returned to playing basketball. In conclusion, this low-intensity resistance training was able to be performed without applying excessive load, which may have caused further damage, and we intend to use Kaatsu training with future patients to help them return as early as possible to full activities.
[PDF (923K)] [References]
Effects of KAATSU training on haemostasis in healthy subjects
T. Nakajima1), H. Takano1), M. Kurano1), H. Iida1), N. Kubota1), T. Yasuda1), M. Kato2), K. Meguro2), Y. Sato1), Y. Yamazaki3), S. Kawashima4), H. Ohshima4), S. Tachibana4), T. Nagata5), T. Abe6), N. Ishii7) and T. Morita2)
1) Department of Ischemic Circulatory Physiology, KAATSU Training, The University of Tokyo
2) Department of CardiovascularMedicine, The University of Tokyo
3) Japan Manned Space Systems Corporation
4) Japan Aerospace Explosion Agency
5) Department of Respiratory Medicine, The University of Tokyo
6) Department of Human and Engineered Environmental Studies, Graduate School of Frontier Science, The University of Tokyo
7) Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo
(Accepted April 4, 2007)
Abstract
Purposes: The KAATSU training is performed under the reduction of muscle blood flow by a specially designed belt (KAATSU belt), which induces blood pooling in capacitance vessels by restricting venous return. However, no prior studies have examined the effects of KAATSU training on haemostasis. The purpose of the present study was to investigate acute effects of KAATSU training on haemostasis including fibrinolytic responses in healthy subjects. Methods: Two protocols have been performed. (1) 6 healthy men (mean age= 48 ± 5 yr) performed KAATSU (160 mmHg) of both thighs for 15 minutes and then KAASTU training combined with low-intensity leg and foot aerobic exercises for ? 10 minutes in hypobaric chamber, which mimics 8000 feet in airflight. (2) Another 7 men (mean age=30 ± 4 yr) performed leg press exercises (30 % 1 RM) with and without KAATSU of both thighs 24 h after bed rest. Blood samples were taken at rest, immediately after KAATSU, and exercises with or without KAATSU, and after exercise. For the investigation of blood fibrinolysis, determinations of tissue-type plasminogen activator (tPA) activity or antigen, plasminogen activator inhibitor (PAI)-1 activity or antigen, fibrin degradation product (FDP) and D-dimer were used. Prothrombin time (PT) and platelet counts were also measured. Results: (1) In hypobaric chamber, KAATSU by itself significantly increased tPA activity, while PAI-1 activity was unchanged. Furthermore, immediately after the exercise, tPA activity increased significantly. (2) During the exercises combined with KAATSU 24 h after bed rest, tPA antigen significantly increased, compared with control exercises, but PAI-1 antigen was unchanged. In both cases, KAATSU training did not induce fibrin formation as assessed by fibrin D-dimer and FDP. Conclusions: This study indicates that potentially favorable changes occur in fibrinolytic factors after KAATSU and KAATSU training in healthy subjects.
Overview of neuromuscular adaptations of skeletal muscle to KAATSU Training
M. Karabulut1), T. Abe2), Y. Sato3) and M. Bemben1)
1) Neuromuscular Laboratory, Department of Health and Exercise Science, University of Oklahoma
2) Department of Human and Engineered Environmental Studies, Gaduate School of Frontier Sciences, The University of Tokyo
3) Department of Ischemic Circulatory Physiology, The University of Tokyo
(Accepted March 21, 2007)
Abstract
Skeletal muscle adapts to a progressive overload, but the response can vary between different modes and intensities of exercise. Generally, a minimal threshold intensity of 65% of the one repetition maximum (1-RM) is needed to elicit muscle hypertrophy; however, recent studies have challenged this hypothesis and have provided evidence that low-intensity training (LIT) combined with vascular restriction (KAATSU) may also elicit increases in muscle size and strength. The physiological aspects of applying vascular restriction during exercise are not fully understood and may be explained by several factors. Examining the results of previous studies may help elucidate the factors responsible for the adaptations associated with vascular restriction in humans. Therefore, the objectives of this review are to summarize current knowledge regarding the physiological adaptations of skeletal muscle after low-intensity exercise combined with vascular restriction, the different training protocols used to elicit adaptations, and suggested areas for future research.
Effects of KAATSU on muscular function during isometric exercise
M. Karabulut1), J. T. Cramer1), E. D. Ryan1), R. L. Anderson1), H. R. Hull1), Y. Sato2), T. Abe2) and M.G. Bemben1)
1) Department of Health and Exercise Sciences, University of Oklahoma
2) Graduate School of Frontier Sciences, The University of Tokyo
(Accepted September 15, 2006)
Abstract
Generally, a threshold intensity of 65% 1-RM will induce muscle hypertrophy; however, recent studies using low-intensity (20% 1-RM) exercise combined with vascular restriction (KAATSU) have demonstrated increases in muscle size and strength. PURPOSE: To investigate the EMG and MMG responses, and percent voluntary activation (PVA) of the vastus lateralis (VL) following exposure to low-intensity intermittent isometric exercise in combination with moderate vascular restriction.METHODS: Twelve males (Age = 23.7 ± 4.1 yrs) participated in 1 familiarization trial and 2 experimental trials (with or without KAATSU) each separated by 48 h. Testing order was: a) Resting blood pressure after 5 min rest; b) 5 min warm-up on a cycle ergometer (50 W, 50-70 rpm); c) 2 preexercise 5-s isometric MVCs, 1 min rest between trials; d) 5 sets of 20 intermittent isometric contractions (2-s on / 1-s off) at 20% of MVC, 30-s interset rest periods; and e) 2 post-exercise isometric 5-s MVCs. RESULTS: There were no significant interactions or main effects for time or session for pre- and post-exercise isometric MVCs, with and without KAATSU, for the following parameters: MVC, PVA, EMG amplitude, EMG mean power frequency (MPF), MMG amplitude, and MMG MPF. Average normalized EMG amplitude increased significantly from repetitions 1-4 to 5-8 to 9-12 and MMG amplitude increased significantly from set 1 to 2 for both the KAATSU and no-KAATSU sessions. CONCLUSION: Intermittent isometric contractions at 20% 1-RM, with or without vascular restriction, are not intense enough to cause significant muscular fatigue.
Hemodynamic responses to simulated weightlessness of 24-h head-down bed rest and KAATSU blood flow restriction
Journal European Journal of Applied Physiology
Publisher Springer Berlin / Heidelberg
ISSN 1439-6319 (Print) 1439-6327 (Online)
Issue Volume 104, Number 4 / November, 2008
Category Original Article
DOI 10.1007/s00421-008-0834-3
Pages 727-737
Subject Collection Biomedical and Life Sciences
SpringerLink Date Thursday, July 24, 2008
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Original Article
Hemodynamic responses to simulated weightlessness of 24-h head-down bed rest and KAATSU blood flow restriction
Toshiaki Nakajima1 Contact Information, Haruko Iida1, Miwa Kurano1, Haruhito Takano1, Toshihiro Morita2, Kentaro Meguro2, Yoshiaki Sato1, Yoshihisa Yamazaki3, Sino Kawashima4, Hiroshi Ohshima4, Shouichi Tachibana4, Naokata Ishii5 and Takashi Abe6
(1) Department of Ischemic Circulatory Physiology, KAATSU Training, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
(2) Department of Cardiovascular Medicine, University of Tokyo, Tokyo, Japan
(3) Japan Manned Space Systems Corporation, Tokyo, Japan
(4) Japan Aerospace Explosion Agency, Tsukuba, Japan
(5) Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo, Japan
(6) Department of Human and Engineered Environmental Studies, Graduate School of Frontier Science, The University of Tokyo, Chiba, Japan
Accepted: 10 July 2008 Published online: 24 July 2008
Abstract The KAATSU training is a unique method of muscle training with restricting venous blood flow, which might be applied to prevent muscle atrophy during space flight, but the effects of KAATSU in microgravity remain unknown. We investigated the hemodynamic responses to KAATSU during actually simulated weightlessness (6° head-down tilt for 24 h, n = 8), and compared those to KAATSU in the seated position before bed rest. KAATSU was applied to the proximal ends of both the thighs. In the seated position before bed rest, sequential incrementing of KAATSU cuff pressure and altering the level of blood flow restriction resulted in a decrease in stroke volume (SV) with an increase in heart rate (HR). KAATSU (150–200 mmHg) decreased SV comparable to standing. Following 24-h bed rest, body mass, blood volume (BV), plasma volume (PV), and diameter of the inferior vena cava (IVC) were significantly reduced. Norepinephrine (NOR), vasopressin (ADH), and plasma renin activity (PRA) tend to be reduced. A decrease in SV and CO induced by KAATSU during the simulated weightlessness was larger than that in the seated position before bed rest, and one of eight subjects developed presyncope due to hypotension during 100 mmHg KAATSU. High-frequency power (HFRR) decreased during KAATSU and standing, while low-frequency/high-frequency power (LFRR/HFRR) increased significantly. NOR, ADH and PRA also increased during KAATSU. These results indicate that KAATSU blood flow restriction reproduces the effects of standing on HR, SV, NOR, ADH, PRA, etc., thus stimulating a gravity-like stress during simulated weightlessness. However, syncope due to lower extremity blood pooling and subsequent reduction of venous return may be induced during KAATSU in microgravity as reported in cases of lower-body negative pressure.
The use of anthropometry for assessing muscle size
M. G. Bemben1), Y. Sato2) and T. Abe3)
1) Department of Health and Exercise Science, University of Oklahoma
2) Department of Ischemic Circulatory Physiology, The University of Tokyo
3) Department of Exercise and Sport Science, Tokyo Metropolitan University
Abstract
The gold standard for assessing muscle size (cross-sectional area and volume) has been magnetic resonance imaging (MRI) and computerized tomography (CT), however, these processes are very expensive and generally require a medical facility, and in the case of CT, can involve exposure to high levels of radiation. The advent of B-mode ultrasound, in conjunction with simple anthropometric measures, such as circumference, can perhaps offer a quick, valid and reliable, and cost effective method to estimate muscle cross-sectional area (CSA) and track changes in muscle CSA following training. The purpose of this study was to document the reliability and accuracy of B-mode ultrasound in combination with anthropometry for assessing Kaatsu training induced changes in muscle-bone CSA. The data from thirty-three young men (mean age, 22.2 ± 5.1 yrs) in four different training groups were combined for the statistical analysis. All subjects were assessed prior to training and three days after the last training session. Anthropometric assessment of the right thigh circumference was taken at the mid point of the thigh (between the lateral condyle of the femur and greater trochanter), and midline anterior (QAT) and posterior (HAT) measures of subcutaneous adipose tissue thickness, at the same level as the circumference measures, was obtained with B-mode ultrasound. The muscle-bone CSA was estimated with the following equation: [? (r - (QAT + HAT) /2)2 ; r=circumference / 2?]. Each subject also had their right thigh imaged, at the same point as the circumference measure, by MRI. The estimated muscle-bone CSA was on average, 21% higher than the MRI measured CSA prior to training but the two methods were significantly (p<0.01) correlated (r=0.81). The correlation between the changes in estimated and MRI measured CSA due to muscle hypertrophy following Kaatsu training was also high (r=0.86) and significant (p<0.01) and only differed on average by 1.8% between two methods. In conclusion, it appears that anthropometry in combination with ultrasound can provide a reliable, accurate, and cost effective alternative method for assessing muscle hypertrophy.
Can KAATSU be used for an orthostatic stress in astronauts?: A case study
H. Iida1), M. Kurano1), H. Takano1), H. Oonuma1), H. Imuta1), N. Kubota1), T. Morita2), K. Meguro2), Y. Sato1), T Abe3), T. Yamazaki4) and T. Nakajima1)
1) Department of Ischemic CirculatoryPhysiology, KAATSU Training, The University of Tokyo
2) Department of Cardiovascular Medicine, The University of Tokyo
3) Department of Human and Engineered Environmental Studies, Graduate School of Frontier Science, The University of Tokyo
4) Japan Manned Space Systems Corporation
(Accepted August 24, 2006)
Abstract
The application of an orthostatic stress such as lower body negative pressure (LBNP) during exercise has been proposed to minimize the effects of weightlessness on the cardiovascular system and subsequently to reduce the cardiovascular deconditioning. The KAATSU training is a novel method for strength training to induce muscle strength and hypertrophy. KAATSU induces venous pooling of blood in capacitance vessels by restricting venous blood flow. Therefore, to investigate whether KAATSU can be used as an orthostatic stress, we examined the effects of KAATSU on the hemodynamic, autonomic nervous and hormonal parameters in one subject. The several parameters were measured by impedance cardiography; heart rate (HR), mean blood pressure (mBP), stroke volume (SV), cardiac output (CO), total peripheral resistance (TPR), and heart rate variability (HRV). These data were obtained before (pre), during and after (post) pressurization (50 and 200 mmHg) on both thighs with KAATSU mini belts, and compared with those in standing. The serum concentration of noradrenaline (NA) and vasopressin (ADH), and plasma rennin activity (PRA) were also measured. The application of 200 mmHg KAATSU decreased SV, which was almost equal to the value in standing. HR and TPR increased in a similar manner as standing with slight change of mBP. High frequency (HFRR), a marker of parasympathetic nervous activity, decreased during both 200 mmHg KAATSU and standing, while LFRR/HFRR, a quantitative marker of sympathetic nervous activity, increased significantly. During KAATSU and standing, NA, PRA and ADH increased. These results indicate that the application of KAATSU on both thighs simulates systemic cardiovascular effects of orthostasis in one gravity (1G), and that KAATSU training appears to be a useful method for potential countermeasure like lower body negative pressure (LBNP) against orthostatic intolerance in space flight as well as strength training to induce muscle strength and hypertrophy.
Effects of a single bout of low intensity KAATSU resistance training on markers of bone turnover in young men
D.A. Bemben1), I.J. Palmer1), T. Abe2), Y. Sato3) and M.G. Bemben1)
1) Department of Health and Exercise Science, University of Oklahoma
2) Department of Human and Engineered Environmental Studies, Graduate School of Frontier Science, The University of Tokyo
3) Department of Ischemic Circulatory Physiology, The University of Tokyo
(Accepted December 21, 2007)
Abstract
Traditional high intensity resistance exercise programs have been shown to have positive effects on bone metabolism. KAATSU resistance training, which combines low intensity resistance exercise with vascular restriction, accelerates muscle hypertrophy, however, the benefits of this type of training on bone have not been established. PURPOSE: To investigate the effects of acute (1 bout) KAATSU training for knee extensors and knee flexors on serum bone biomarkers in young men, 18-30 years of age. METHODS: Nine males performed two test sessions, KAATSU (vascular restriction + low intensity resistance exercise) and control (low intensity resistance exercise only) 48 hours apart in random order. The exercise protocol consisted of 1 set of 30 reps followed by 3 sets of 15 reps with 30 seconds rest between sets at 20% 1-RM for both muscle groups. On both days, fasting blood draws were obtained immediately prior to exercise, immediately post exercise and 30 minutes post exercise for the measurement of the bone formation (bone-specific alkaline phosphatase, BAP) and bone resorption (cross-linked N-telopeptide of type I collagen, NTx) markers. Hematocrit was measured at each sample time to estimate plasma volume changes. Serum samples were aliquoted and frozen at -70°C until the BAP (Metra BAP EIA kit, Quidel Corporation) and NTx (Osteomark® NTx Serum, Wampole Laboratories) assays were performed. RESULTS: KAATSU training resulted in greater plasma volume decreases (p<.05) immediate post exercise compared to the control session. There was a significant (p<.05) training x time effect for NTx levels. 30 minute post exercise NTx levels (21.4±3.4 nM BCE) significantly (p<.05) decreased from baseline (24.9±4.3 nM BCE) after KAATSU training but not in response to the control training. After correcting for plasma volume shifts, significant decreases in serum NTx were observed for both KAATSU post exercise samples. There were no significant (p>.05) training or time effects for BAP. CONCLUSION: A single bout of KAATSU trining resulted in decreases in the bone resorption marker (NTx) but had no effect on the bone formation marker (BAP). The NTx response to KAATSU was not mediated by shifts in plasma volume.
KAATSU resistance training decreased the sinus pause in a patient demonstrating sick sinus syndrome. A case report
I. Satoh1)
1) Satoh Heart Clinic
(Accepted August 30, 2006)
Abstract
The effectiveness of KAATSU resistance training (Kaatsu) has been established as a method not only to increase muscle size and power but also to benefit patients with orthopedic and cardiac diseases. The method is a low-intensity resistance exercise (20?30% of one repetition maximum, 1RM) with a restriction of the venous return using a specially designed pressurized cuff or belt at the proximal end of the upper or lower extremities. The increases of growth hormone (GH) and insulin-like growth factor-1 (IGF-1) by Kaatsu resistance training are considered to play an important role in elucidating the mechanism of Kaatsu. In this case, the sinus pause of a patient with sick sinus syndrome (SSS) decreased to approximately 40% with Holter ECG monitoring after Kaatsu resistance training. The mechanism regarding such an improvement by Kaatsu is herein discussed. Therefore, an additional effect of Kaatsu is reported concerning the decreased sinus pause observed in a SSS patient.
Resistance exercise combined with KAATSU during simulated weightlessness
N. Kubota1)7), H. Takano1), T. Tsutsumi7), M. Kurano1), H. Iida1), T. Yasuda1), K. Meguro1), T. Morita2), Y. Sato1), S. Kawashima3), Y. Yamazaki4), H. Ohshima3), S. Tachibana3), N. Ishii6), T. Abe5) and T. Nakajima1)
1) Department of Ischemic Circulatory Physiology, KAATSU Training, University of Tokyo
2) Department of Cardiovascular Medicine, University of Tokyo
3) Japan Aerospace Exploration Agency
4) Japan Manned Space Systems Corporation
5) Department of Human and Engineered Environmental Studies, Graduate School of Frontier Science, The University of Tokyo
6) Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo
7) Division of Cardiology, Showa University Fujigaoka Hospital
(Accepted July 25, 2008)
Abstract
The application of a gravity-specific stress (e.g. LBNP), in combination with exercise, prevents cardiovascular deconditioning in space flight. KAATSU training is a method to induce blood pooling in capacitance vessels by restricting venous return (as with LBNP) and which when combined with low-intensity resistance (RE) exercise produces remarkable muscle mass and muscle strength gains. The purpose of this study was to investigate the hemodynamic and neurohumonal responses induced by KAATSU in combination with leg RE (30 % 1 RM), during simulated weightlessness (6°head-down tilt for 24 h, n=7). Following 24 h bed rest 6° head-down tilt, body mass was decreased from 75.3 ± 3.9 to 73.3 ± 3.8 Kg (P<0.01). Blood volume (BV) and plasma volume (PV) were reduced by ?4.4 ± 1.4% and ?7.9 ± 2.5%, respectively. During RE, BV and PV were significantly decreased; the changes with KAATSU induced a lower-body venous pooling, resulting in a sustained decrease in stroke volume (SV; from 77.0 ± 4.4 ml to 55.9 ± 5.1 ml; P<0.01) that was comparable to resting SV while standing. Consequently, RE heart rate (HR) was greater with KAATSU. The serum concentrations of plasma renin activity (PRA), vasopressin (ADH), noradrenaline (NOR), and lactate were also significantly elevated during RE with KAATSU as compared to control RE. These hemodynamic and neurohumoral responses following head-down tilt and during RE closely approximate the gravity-specific stress observed with LBNP. Thus, when used in combination with RE, KAATSU may be a useful countermeasure in microgravity.
Effect of knee extension exercise with KAATSU on forehead cutaneous blood flow in healthy young and middle-aged women
K. Kusuhara1), T. Fujita2), T. Yasuda2), T. Nakajima3), Y. Sato1)3), Y. Miyagi4), Y. Murakami4) and T. Abe1)
1) Department of Human and Engineered Environment, Graduate School of Frontier Science, The University of Tokyo
2) Department of Exercise and Sport Science, Tokyo Metropolitan University
3) Department of Ischemic Circulatory Physiology, The University of Tokyo
4) BodybyVital Research Laboratory
(Accepted September 15, 2006)
Abstract
Dynamic exercise induces changes in the redistribution of whole-body organ-tissue blood circulation, including cutaneous blood circulation. We hypothesized that limb exercise combined with the restriction of muscular blood flow (KAATSU) may influence cutaneous blood flow redistribution. To examine this hypothesis, forehead (supraorbital) cutaneous blood flow was compared in women performing exercises with and without KAATSU. Ten young and middle-aged female subjects in the supine position performed three sets of 15 repetitions of unloaded unilateral knee extension exercises (30-s rest between sets). Blood flow was calculated from blood velocity and red blood cell mass (blood flow = velocity * mass) determined by laser blood flowmetry. While exercise without KAATSU did not induce alterations in velocity and mass (hence, no alterations in blood flow) throughout the entire exercise series, exercise with KAATSU induced increases (P<0.05) in blood flow owing to increases in velocity. These increases were not eliminated during the rest periods between exercise sets. Heart rate (HR) increased (P<0.05) with the second and third sets of exercises with KAATSU compared with HR before exercise initiation, and was higher than the HR resulting from a corresponding set of exercises without KAATSU. There were no changes in blood lactate and hematocrit in both types of exercises. Norepinephrine increased (P<0.05) at the completion of the exercise sets. These results suggest that forehead cutaneous blood circulation was increased by unloaded KAATSU leg exercise.
The horse: An alternative model for KAATSU research
C. F. Kearns1), Y. Sato2) and T. Abe1)3)
1) Department of Exercise and Sport Science, Tokyo Metropolitan University
2) Department of Ischemic Circulatory Physiology, University of Tokyo
3) Graduate School of Frontier Science, The University of Tokyo
(Accepted March 5, 2006)
Abstract
In order to produce significant muscle hypertrophy, a training intensity of greater than 65% of the 1-repetition maximum (1-RM) is generally believed to be required. However, this concept has been challenged recently by data from studies that have combined 20%-50% 1-RM with restriction of venous blood flow from the working muscle, referred to as KAATSU-training. These studies have demonstrated significant gains in muscle size and strength in as little as 2 weeks in humans. The KAATSU-training model may have utility in models other than humans; several recent papers have investigated the safety and potential utility of KAATSU-training in an equine model. The purpose of this brief review is to discuss the horse as a viable model of KAATSU-training and discuss the available data using this model thus far.
Blood pressure response to slow walking combined with KAATSU in the elderly
M. Sakamaki1), S. Fujita1), Y. Sato2), M. G. Bemben3) and T. Abe1)
1) Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo
2) Department of Ischemic Circulatory Physiology, Graduate School of Medicine, The University of Tokyo
3) Department of Health and Exercise Science, University of Oklahoma
(Accepted August 14, 2008)
Abstract
The purpose of the present study was to examine the blood pressure and heart rate response to walking with and without blood flow restriction (KAATSU-walk) in the elderly. Seven active subjects (2 men, 5 women) aged between 64 to 78 years (mean age, 68.9 ± 6.3 years) performed walking test without (Control) and with KAATSU (cuff pressure 160 mmHg and 200 mmHg) on separate days. The exercise consisted of level walking at 67 m/min (4 km/hr) for 20 min. Systolic (SBP) and diastolic (DBP) blood pressure was recorded using an automatic blood pressure monitor, and mean arterial pressure (MAP) was calculated [MAP = DBP + (SBP - DBP)/3]. Heart rate (HR) and ratings of perceived exertion (RPE) were also recorded during the test. There were no significant differences (P>0.05) in blood pressure responses between the Control and KAATSU-160mmHg exercise, however significantly higher blood pressures were observed for the KAATSU-200mmHg exercise (112-127mmHg for MAP) compared to the Control. However, these values are still lower than those of previous reported during moderate to heavy resistance exercise. The correlations between HR and MAP during each exercise condition were all statistically significant (range from r=0.83 to r=0.94; p<0.05). However, the intercept of the curve was highest in KAATSU-200mmHg exercise (i.e. MAP response to the same HR was higher), suggesting the increased total peripheral resistance with high occlusive pressure. In conclusion, our results indicate that during slow walk exercise with KAATSU, level of occlusive pressure can significantly impact upon the HR and MAP responses in the elderly, These findings are consistent with the idea that the occlusive pressure by itself can significantly modulate the cardiovascular response during low-intensity KAATSU-walk.
Comparison of KAATSU and Traditional Resistance Training on Muscle and Blood Vessel Function in Young Men: 1617: Board #164 May 28 3:30 PM - 5:00 PM
Kim, SoJung; Sherk, Vanessa; Bemben, Michael FACSM; Bemben, Debra FACSM
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University of Oklahoma, Norman, OK.
Email: sophie74@ou.edu
(No relationships reported)
Previous studies have shown that low-intensity resistance training with restricted blood flow, known as "KAATSU Training", increases muscle strength and size. Its effects on blood vessel function, however, have not been examined.
PURPOSE: To compare the effects of a short term KAATSU resistance training protocol and traditional high intensity resistance training on muscle strength, crosssectional area (MCSA) and blood vessel function in young untrained men.
METHODS: Male volunteers were randomly assigned to either a KAATSU resistance training group (KT, n=7) or a traditional resistance training group (RT, n=7). Both KT and RT groups performed 3 weeks of resistance training for leg press (LP), knee extension (KE) and knee flexion (KF) isotonic exercises. Sessions consisted of 5-10 minutes of warm-up, followed by 2 sets of 10 reps at either 20% 1RM for the KT or 80% 1RM for RT. For the KT group, a pressure cuff was placed on the proximal end of both thighs and inflated to a pressure determined by each subject
Effects of Whole-Body Low-Intensity Resistance Training With Slow Movement and Tonic Force Generation on Muscular Size and Strength in Young Men
Tanimoto, Michiya; Sanada, Kiyoshi; Yamamoto, Kenta; Kawano, Hiroshi; Gando, Yuko; Tabata, Izumi; Ishii, Naokata; Miyachi, Motohiko
Abstract
Tanimoto, M, Sanada, K, Yamamoto, K, Kawano, H, Gando, Y, Tabata, I, Ishii, N, and Miyachi, M. Effects of whole-body low-intensity resistance training with slow movement and tonic force generation on muscular size and strength in young men. J Strength Cond Res 22(6): 1926-1938, 2008-Our previous study showed that relatively low-intensity (~50% one-repetition maximum [1RM]) resistance training (knee extension) with slow movement and tonic force generation (LST) caused as significant an increase in muscular size and strength as high-intensity (~80% 1RM) resistance training with normal speed (HN). However, that study examined only local effects of one type of exercise (knee extension) on knee extensor muscles. The present study was performed to examine whether a whole-body LST resistance training regimen is as effective on muscular hypertrophy and strength gain as HN resistance training. Thirty-six healthy young men without experience of regular resistance training were assigned into three groups (each n = 12) and performed whole-body resistance training regimens comprising five types of exercise (vertical squat, chest press, latissimus dorsi pull-down, abdominal bend, and back extension: three sets each) with LST (~55-60% 1RM, 3 seconds for eccentric and concentric actions, and no relaxing phase); HN (~80-90% 1RM, 1 second for concentric and eccentric actions, 1 second for relaxing); and a sedentary control group (CON). The mean repetition maximum was eight-repetition maximum in LST and HN. The training session was performed twice a week for 13 weeks. The LST training caused significant (p < 0.05) increases in whole-body muscle thickness (6.8 ± 3.4% in a sum of six sites) and 1RM strength (33.0 ± 8.8% in a sum of five exercises) comparable with those induced by HN training (9.1 ± 4.2%, 41.2 ± 7.6% in each measurement item). There were no such changes in the CON group. The results suggest that a whole-body LST resistance training regimen is as effective for muscular hypertrophy and strength gain as HN resistance training.
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Acute Hormonal Responses To Restriction Of Leg Muscle Blood Flow During Walking: 564 Board #155 2:00 PM - 3:30 PM
Abe, Takashi; Sato, Yoshiaki; Kearns, Charles F.; Yoshitomi, Aiko
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1Tokyo Metropolitan University, Tokyo, Japan.
2Japan KAATSU Training Research Institute, Tokyo, Japan.
3Schering-Plough Research Institute, Kenilworth, NJ.
Email: abebe@comp.metro-u.ac.jp
Low-intensity resistance exercise (20% of one-repetition maximal) combined with restriction of muscle blood flow (namely KAATSU) increases plasma growth hormone (GH) concentration. In general, walking slowly has no effect on acute GH response.
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PURPOSE
To examine the acute responses of serum GH, free testosterone, and cortisol to slow walking combined with KAATSU.
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METHODS
11 male college students performed walking (50 m/min for five 2 min bouts; 1 min rest between bouts) with and without KAATSU (the proximal end of their thigh compressed at 130% of resting systolic blood pressure throughout the walking session) on separate days. Venous blood samples were obtained prior to the start of exercise (Pre), and immediately (IP), 15- (15P) and 60-min (60P) after exercise.
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RESULTS
Serum GH concentration was elevated (P<0.01) from Pre [1.72 (0.83) ng/ml] to IP [12.4 (3.2) ng/ml] and 15P [13.1 (2.4) ng/ml] in the walking with KAATSU. Free testosterone was also elevated (P<0.05) from Pre [12.7 (1.2) pg/ml] to IP [16.0 (1.3) pg/ml] in the walking with KAATSU. Neither GH [Pre, 1.67 (0.97) ng/ml; IP, 1.39 (0.91), 15P, 1.26 (0.92)] nor free testosterone [Pre, 14.3 (1.3) pg/ml; IP, 14.1 (1.2)] increased during the walking without KAATSU. Cortisol concentration showed a gradual decrease (P<0.05) during the experiments in both walking with and without KAATSU.
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CONCLUSIONS
The results of the present investigation with young male students indicated that slow walking with KAATSU caused greater responses in serum GH and free testosterone compared to normal slow walking.
Muscle Oxygenation and Pulse Oxygen Saturation during Walking Combined with Restriction of Leg Muscle Blood Flow: 2708: Board #216 3:PM - 4:PM
Kearns, Charles F.; Abe, Takashi; Kimura, Naoto; Sato, Yoshiaki
Free Access
Author Information
1Tokyo Metropolitan University, Tokyo, Japan.
2Nippon Sports Science University, Tokyo, Japan.
3University of Tokyo, Tokyo, Japan.
Email: charles_kearns@yahoo.com
We reported that chronic walk training combined with restriction of leg muscle blood flow (KAATSU) increases thigh muscle size and strength. A variety of factors are thought to influence the KAATSU walk-induced muscle hypertrophy, such as enhanced endocrine responses and muscle oxygenation status. Although the precise mechanism is not fully understood, oxygenation status of working muscle seems to play an important role in stimulation of KAATSU-induced muscle hypertrophy.
PURPOSE: To investigate the response of leg muscle oxygenation and pulse oxygen saturation during KAATSU walk.
METHODS: Seven young men [mean (SD) age: 22.1 (2.9) yrs] performed acute treadmill walking with (KAATSU-walk) and without KAATSU (Control-walk) on same day. The exercise consisted of walking at 50 m/min for five 2-min bouts, with a 1-min rest between bouts (total time 14 min). A specially designed elastic belt (50 mm wide) was placed around the most proximal portion of each leg during KAATSU-walk exercise. The belt contained a pneumatic bag along its inner surface that was connected to an electronic air pressure control system that monitored the restriction pressure (Kaatsu-Master, Tokyo). The belt air pressure was set at 200 mmHg for the restriction stimulus during KAATSU-walk test. A near-infrared continuous-wave spectroscopic monitor (NIRS) was used to measure the peripheral muscle oxygenation in the vastus lateralis (VL) and gastrocnemius medialis (MG) muscles. Pulse oxymetry (SpO2) was monitored in both the hands and feet. Oxygen uptake during KAATSU-walk and Control-walk was measured on separate days.
RESULTS: Mean heart rate was higher (P < 0.05) at the latter half of the walking session in the KAATSU-walk than in the Control-walk. Mean oxygen uptake was higher (P < 0.01) in the KAATSU-walk (687 ml/min) than in the Control-walk (612 ml/min). There was no difference in SpO2 (both hand and foot) during KAATSU-walk than during Control-walk (97?99%). On the other hand, muscle oxygenation level was lower (-16.4%; P < 0.01) in the VL (54.4 ± 6.9% versus 65.1 ±5.2%) and was lower (-17.1%; P < 0.01) in the MG (51.0 ± 7.5% versus 61.5 ± 3.2%) during KAATSU-walk than during Control-walk, respectively.
CONCLUSION: The lower muscle oxygenation level during KAATSU-walk may be one of the key factors for the muscular hypertrophy. The decrease in muscle oxygenation was, however, likely due to the pooling of venous blood in the working KAATSU muscle. Further study is needed to determine whether muscle is hypoxic during KAATSU-walk exercise.
Effects of Walk or Squat Training Combined with Restriction of Leg Muscle Blood Flow on Hip, Thigh and Calf Muscle Hypertrophy: 1773: Board # 146 3:00 PM - 4:00 PM
Abe, Takashi; Kearns, Charles F.; Yasuda, Tomohiro; Sato, Yoshiaki
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1 Tokyo Metropolitan University, Tokyo, Japan.
2University of Tokyo, Tokyo, Japan.
Email: abebe@comp.metro-u.ac.jp
Low-intensity resistance squat or walk training combined with restriction of leg muscle blood flow (KAATSU) increases thigh muscle size and strength. However, it is unknown whether muscle hypertrophy occurs in training movement-related accessory muscles, such as hip and calf, following KAATSU squat or walk training.
PURPOSE: To investigate the effects of 2 types (walk or squat) of exercise training combined with KAATSU on hip, thigh and calf muscle size and strength.
METHODS: 33 healthy young men [mean (SD) age: 22.4 (3.5) yrs] were randomized into 4 training groups: treadmill walking (50m/min, 5 sets of 2-min bout with a 1 -min rest between bouts, twice per day, 6 days per week for 3 weeks) with or without KAATSU (KAATSU-walk, n=9 or Control-walk, n=8), and squat exercise (20% of 1-RM, 4 sets, twice per day, 6 days per week for 2 weeks) with or without KAATSU (KAATSU-squat, n=9 or Control-squat, n=7). A specially designed elastic belt (50 mm wide) was placed around the most proximal portion of each leg during training with KAATSU. The belt contained a pneumatic bag along its inner surface that was connected to an electronic air pressure control system that monitored the restriction pressure. Because the subjects adapted to the occlusion stimulus during the training, the restriction pressure of 160-230 mmHg was selected for occlusive stimulus. Skeletal muscle volume was measured using magnetic resonance imaging (MRI) 1.5 T-scanners with spin-echo sequence. Contiguous transverse MRI images (about 100 slices) with a slice thickness of 1 -cm were obtained from the L4/L5 to the ankle joint before and after training. Quadriceps, gluteus maximus, and triceps surea muscle volume were calculated from the summation of digitized cross-sectional area. Maximum isometric knee extension strength was measured before and after training.
RESULTS: There were no changes (P >0.05) in muscle volume and maximum isometric strength for Control-walk and Control-squat groups. Maximum isometric knee extension strength increased (P <0.05) 11.1% for KAATSU-squat and 10.4% for KAATSU-walk. Quadriceps muscle volume increased (P <0.01) 4.1% and 7.5%, respectively, in KAATSU-walk and KAATSU-squat groups. Gluteus maximus muscle volume increased 8.4% (P <0.01) in KAATSU-squat but did not increase in KAATSU-walk (-0.6%). On the other hand, triceps surea muscle volume increased (P <0.05) 5.7% in KAATSU-walk but did not increase (P >0.05) in KAATSU-squat (1.2%).
CONCLUSION: Skeletal muscle hypertrophy occurred not only thigh muscle, but also in training movement-related accessory muscles following low-intensity KAATSU training.
Effects of Vascular Restriction on Muscular Function during Intermittent Submaximal Isometric Exercise: 2246: Board #159 June 1 8:00 AM - 9:30 AM
Karabulut, Murat; Cramer, Joel; Ryan, Eric; Anderson, Richard; Hull, Holly; Sato, Yoshiaki; Abe, Takashi; Bemben, Michael FACSM
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1University of Oklahoma, Norman, OK.
2The University of Tokyo, Tokyo, Japan.
Email: muratk@ou.edu
It is generally accepted that a threshold intensity of 65% 1-RM is needed to induce muscle hypertrophy; however, recent studies using low-intensity resistance exercise (20% 1-RM) combined with vascular restriction (KAATSU) have also been able to demonstrate increases in muscle size and strength.
PURPOSE: To investigate EMG and MMG responses of the vastus lateralis (VL) before, during, and after low intensity intermittent isometric exercise in combination with moderate vascular restriction and to examine the percent voluntary activation (PVA) of the VL.
METHODS: Twelve healthy males volunteered to participate in this study (mean + SD age = 23.7±4.1 years). Each participant visited the laboratory 3 times: one familiarization trial and two experimental trials, separated by at least 48 h. The two experimental trials consisted of the same testing and isometric exercise protocol; however, the participants experienced either the KAATSU or no-KAATSU conditions in random order. For the experimental trials, the following procedures were performed in order: a) Resting blood pressure assessment after 5 min rest (for the KAATSU trial only), b) five-minute warm-up on a stationary cycle ergometer with a power output of 50 W and a pedaling cadence of 50-70 rpm, c) two pre-exercise 5-s isometric MVCs with 1 min rest between trials, d) five sets of 20 intermittent isometric contractions (2-s on and 1 -s off) at 20% of MVC with a 30-s interset rest period, and e) two post-exercise isometric 5-s MVCs with 1 min rest between trials.
RESULTS: For MVC torque, PVA, EMG amplitude, EMG mean power frequency (MPF), MMG amplitude, and MMG MPF, there was no interaction and no main effects for time or session for the pre- and post-exercise isometric MVCs with and without KAATSU. The average normalized EMG amplitude (%MVC) increased from repetitions 1-4 to 5-8 to 9-12 and MMG amplitude increased significantly from set 1 to 2 for both the KAATSU and no-KAATSU sessions.
CONCLUSIONS: The present study demonstrated no significant change in post-exercise torque values and % activation, suggesting that the exercise task was not intense enough to cause muscular fatigue in either treatment condition.
Proposal of alternative mechanism responsible for the function of high-speed swimsuits
Eisuke Kainuma1), Mayumi Watanabe1), Chikako Tomiyama-Miyaji2), Masashi Inoue1), Yuh Kuwano1), HongWei Ren1) and Toru Abo1)
1) Department of Immunology, Niigata University School of Medicine
2) School of Health Sciences, Faculty of Medicine, Niigata University
(Received December 12, 2008)
(Accepted December 17, 2008)
ABSTRACT
Since many top swimmers wearing Speedo LZR Racer swimsuits have broken world records, it is considered that the corset-like grip of suit supports the swimmers to maintain flexibility of movement and reducing water resistance. We propose an alternative mechanism to explain this phenomenon. The suits are so tight that the blood circulation of swimmers is suppressed. This effect accelerates the anaerobic glycolysis system but rather suppresses the aerobic mitochondrial respiration system. Because of the prompt production of ATP in the glycolysis system, the swimmers, especially in short distance competitions, obtain instantaneous force in white fibers of the skeletal muscles.
Muscle Hypertrophy following Multi-joint Low Intensity Resistance Training with Single-joint Blood Flow Restriction: 1615: Board #162 May 28 3:30 PM - 5:00 PM
Abe, Takashi; Brechue, William F. FACSM; Fujita, Satoshi; Ogasawara, Riki; Yasuda, Tomohiro; Sato, Yoshiaki
Free Access
Author Information
1University of Tokyo, Kashiwa, Japan. 2United States Military Academy, West Pint, NY. (Sponsor: William F. Brechue, FACSM)
Email: abe@k.u-tokyo.ac.jp
(No relationships reported)
Low-intensity, single-joint resistance exercise training combined with restricted muscle blood flow results in significant increases in muscle size and strength. What remains poorly understood is whether muscle enlargement and strength changes occur in lowintensity multi-joint exercise where only a portion of the active musculature is exposed to restricted blood flow.
PURPOSE: To determine the impact of low-intensity multi-joint resistance exercise on strength and the hypertrophic response of muscles proximal (non-restricted) and distal (restricted) to blood flow restriction (KAATSU).
METHODS: Bench press training (30% of 1-RM, 4 sets, 30 sec rest between sets) was performed with (BP-K; n=5) and without (BP-C; n=5) KAATSU blood flow restriction; the proximal end of their upper arm compressed at 80-120% of resting systolic blood pressure throughout the exercise session. Training was conducted twice per day, six days per week for 2 weeks. Each morning prior to the training session, triceps brachii and pectoralis major muscle thickness (MTH) were measured by B-mode ultrasound (Aloka SSD-500, Tokyo). Serum creatine phosphokinase, myoglobin, growth hormone, testosterone, insulin-like growth factor (IGF)-1 and IGF-BP3 concentrations were measured prior to and 2-days following the last training session.
RESULTS: There were no changes in anabolic hormones or serum markers for muscle damage in either group. 2-weeks of training led to a significant increase (P<0.05) in 1-RM bench press in BP-K (+6%), but not in BP-C (-2%). Triceps and pectoralis major MTH increased 8% (pre, 36.1 mm; post 38.9 mm, P<0.01) and 16% (pre, 23.7 mm; post, 27.6 mm, P<0.01), respectively, in BP-K, but not in BP-C (-1% and 2%, respectively).
CONCLUSIONS: Low-intensity Kaatsu training involving a multi-joint exercise leads to a significant increase in muscular strength and hypertrophy in skeletal muscles proximal and distal to the blood-flow restriction; suggesting that the mechanism of KAATSU training affects adaptation upstream and downstream of the pressure cuff and blood flow restriction.
Neuromuscular Fatigue during Low-Intensity Dynamic Exercise in Combination with Externally Applied Vascular Restriction: 1768: Board #121 May 29 9:00 AM - 10:30 AM
Karabulut, Murat; Cramer, Joel T.; Abe, Takashi; Sato, Yoshiaki; Bemben, Michael G. FACSM
Free Access
Author Information
1University of Oklahoma, Norman, OK. 2University of Tokyo, Chiba, Japan. 3University of Tokyo, Tokyo, Japan.
Email: muratk@ou.edu
(No relationships reported)
PURPOSE: The present study investigated neuromuscular fatigue during lowintensity resistance exercise (i.e., 20% 1RM) combined with (KAATSU) and without (control, CON) vascular restriction.
METHODS: Fourteen healthy males (mean + SE age= 23.7±1.1 years) volunteered to perform 2 pre-exercise isometric maximum voluntary contractions (MVCs) before and after 5 sets of 20 dynamic constant external resistance (DCER) leg extension exercises at 20% of 1RM. During one of the two trials seperated by at least 48 hours, vascular restriction (KAATSU) was applied to the proximal thighs using pneumatic cuffs (50 mm wide) connected to an electronic pressure control system. No KAATSU was aplied to the CON condition. Surface electromyography (EMG) was recorded from the vastus lateralis during all MVCs and the DCER leg extensions. Twitch interpolation was used to assess the percent of maximal voluntary activation (%VA) during the MVCs.
RESULTS: After the KAATSU condition, the decreases (p<0.05) in MVC force, %VA, EMG amplitude, and potentiated twitch force were more profound than the changes observed after the CON condition. However, during the DCER exercises, the increases (p<0.05) in EMG amplitude and decreases (p<0.05) in EMG mean power frequency were similar for both the KAATSU and CON conditions.
CONCLUSIONS: These findings indicated that low-intensity leg extension exercises at 20% 1RM combined with KAATSU resulted in a greater post-exercise fatigue effect than the CON condition, despite the similar EMG changes during the DCER exercises. Our findings suggest that the KAATSU-induced fatigue may have been due to a combination of peripheral and central manifestations.
Skeletal muscle size and strength are increased following walk training with restricted leg muscle blood flow: implications for training duration and frequency
T. Abe1)2), C. F. Kearns2), S. Fujita1), M. Sakamaki1), Y. Sato1) and W. F. Brechue3)
1) Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Japan
2) Department of Exercise and Sport Science, Tokyo Metropolitan University, Tokyo, Japan
3) Center for Physical Development Excellence, United States Military Academy, West Point, NY, USA
(Accepted August 12, 2009)
Abstract
The purpose of this study was to investigate once-daily walk training with restricted leg blood flow (KAATSU) on thigh muscle size and strength. Twelve young men performed walk training: KAATSU-walk training (n=6) and control (no KAATSU-walk; n=6). Training was conducted once daily, 6 days per week, for 3 weeks. Treadmill walking (50 m/min) was performed for 5 sets of 2-min bouts interspersed with 1-min rest periods. The KAATSU-walk group wore pressure cuff belts (5 cm wide) on both legs during training, with incremental increases in external compression starting at 160 mmHg and ending at 230 mmHg. Thigh muscle volume and isometric and 1-repetition maximal (1-RM) strength were measured before and after training. In the KAATSU-walk group, quadriceps and hamstrings muscle volume increased 1.7 and 2.4% (both P<0.05), respectively, following training. One-RM leg press and leg curl increased 7.3 and 8.6% (both P<0.05), respectively, following KAATSU-walk training. Also, isometric knee extension strength (4.4%; P<0.01), but not knee flexion strength (1.7%), increased following KAATSU-walk training. There were no changes in muscle volume or strength in the control-walk group. These results confirm previous work showing that the combination of slow walk training and leg muscle blood flow restriction induces muscle hypertrophy and strength gains. However, the magnitude of change in muscle mass and strength following once-daily KAATSU-walk training was approximately one-half that reported for twice-daily KAATSU-walk training over a 3-week period. These results in combination with previous observations lead to the conclusion that the impact of KAATSU-walk training on muscle size and strength is related to an ability to accomplish a high number of training bouts within a compressed training duration. Second, frequency-dependent muscle enlargement appears to be associated with KAATSU-walk training.
Muscle Tissue Oxygenation and Force Production during Low-intensity Resistance Exercise with Blood Flow Restriction: 1769: Board #122 May 29 9:00 AM - 10:30 AM
Fujita, Satoshi; Kimura, Naoto; Sugaya, Masato; Ozaki, Hayao; Sato, Yoshiaki; Abe, Takashi
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1University of Tokyo, Chiba, Japan. 2Nippon Sport Science University, Tokyo, Japan.
(Sponsor: William F. Brechue, FACSM)
Email: fujita@k.u-tokyo.ac.jp
(No relationships reported)
We have recently demonstrated that an acute bout of low-intensity resistance exercise combined with blood flow restriction (Kaatsu exercise) stimulates both muscle protein synthesis and translation initiation. Recently, myocardial ischemia-reperfusion has also been shown to activate the signaling pathway of translation initiation.
PURPOSE: To investigate the changes in muscle tissue oxygenation during Kaatsu exercise to assess the level of ischemia-reperfusion condition in skeletal muscle.
METHODS: Six subjects performed three separate experiments randomly; Control (CON), Kaatsu (KAT, blow restriction via pressure cuff), or High-intensity (HI) exercise group. CON and KAT performed a bout of unilateral knee extension exercise at 20% of 1-repetition maximum (1-RM) strength, while HI group exercised at 70% 1-RM. Vastus lateralis and rectus femoris muscle tissue oxygenation (HbO2) was assessed using near-infrared spectroscopy (NIRS), and isometric muscle strength was assessed immediately before and after the exercise bout.
RESULTS: In the KAT, resting HbO2 was reduced significantly (rest, 61.7%; cuff, 54.5%; p<0.05) in response to blood flow restriction. During exercise, HbO2 decreased further in KAT and reached the same level of tissue oxygenation as HI (KAT, 45.6%; HI, 44.8%; p<0.05 vs. rest for both groups) whereas HbO2 did not change in CON. During the recovery period, HbO2 was restored to the resting level both in CON and HI group (63.9 and 69.1% for CON and HI, respectively), whereas it was still significantly depressed in KAT group (51.4%, p<0.05). Muscular strength was significantly reduced after the bout of exercise in KAT and HI (-45 and -25% for KAT and HI, respectively; p<0.05), whereas no change in strength was observed in CON (-1.8%).
CONCLUSION: Although a decreased tissue oxygenation during exercise and recovery period may contribute to muscle fatigue, sustained ischemic condition during recovery period in KAT suggests a non-significant ischemia-reperfusion during low intensity resistance exercise with blood flow restriction.
Effects of short-term, low-intensity resistance training with vascular restriction on arterial compliance in untrained young men
S. J. Kim1), V. D. Sherk1), M. G. Bemben1) and D. A. Bemben1)
1) Department of Health and Exercise Science, University of Oklahoma, Norman, OK, USA
(Accepted July 17, 2009)
Abstract
Previous studies have shown that low-intensity resistance training with restricted blood flow, known as KAATSU training, increases muscle strength and size. Its effects on blood vessel function, however, have not been examined. We compared the effects of a short-term KAATSU resistance training protocol and traditional high-intensity resistance training on muscle strength and blood vessel function in young, untrained men. Male volunteers were randomly assigned to a KAATSU resistance training group (KR, n=10), a traditional resistance training group (RT, n=10), or a KAATSU-only group (K, n=10). Both KR and RT groups trained 3 times per week for 3 weeks doing leg press (LP), knee flexion (KF), and knee extension (KE) isotonic resistance exercises. Training sessions consisted of 5-10 min of warm-up, followed by 2 sets of 10 repetitions at 80% of 1 repetition maximum (1-RM) for the RT group, while the KR group performed the resistance exercises with vascular restriction at a load of 20% of 1-RM. The K group had only the vascular restriction treatment for 3 weeks. Muscle strength (1-RM) and arterial compliance (pulse contour analysis) were assessed at baseline and after training. Both the KR and RT groups did not show changes in arterial compliance of the large or small arteries (P>0.05) after training. There were significant time effects (P<0.05 pre- vs. posttraining); however, resistance training generally resulted in greater relative improvements in strength. Arterial compliance of the large and small arteries was not affected by the either the KAATSU or traditional high-intensity resistance training interventions.
Circuit training without external load induces hypertrophy in lower-limb muscles when combined with moderate venous occlusion
N. Ishii1), H. Madarame1), K. Odagiri2), M. Naganuma3) and K. Shinoda3)
1) Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo
2) Odagiri Hospital
3) PHENIX Co., Ltd.
Abstract
The present study investigated whether circuit training with body weight alone (no external load) can cause muscular hypertrophy when combined with moderate venous occlusion (‘Kaatsu Training’). Healthy women (mean age, 32.7 ± 4.0 yr; n=22) were randomly assigned into the occlusive training group (OCC, n=11) and the normal training group (NOR, n=11). Both groups performed the same circuit-training regimen consisting of six, successive exercises for muscles in the upper and lower limbs and the trunk, at a frequency of 3 sessions/wk. Each session lasted for 5-10 min. In OCC group, proximal ends of the upper and lower limbs of both sides were moderately compressed by means of ‘KAATS Sportswear’, to restrict the venous blood flow during the exercises (preset pressure, 50-80 mmHg and 80-120 mmHg for upper and lower limbs, respectively). Cross-sectional area (CSA) of the thigh muscle was measured with spiral computer tomography. After an 8-wk period of training, the muscle CSA of both right and left limbs showed significant increases by ?3% (P<0.05) in the OCC group, whereas there was no change for the NOR group. To propose a mechanism for these findings, the acute effects of the same exercise regimen combined with occlusion on plasma concentration of growth hormone (GH) were further investigated with male subjects (n=2). The circuit exercise with occlusion elicited a dramatic increase in plasma GH, whereas that without occlusion did not, although statistical analysis could not be made. The results indicate that circuit training with only body weight can cause hypertrophy in lower-limb muscles when combined with moderate venous occlusion, but the exact mechanism is not yet understood.
Fatigue Characteristics during Maximal Concentric Leg Extension Exercise with Blood Flow Restriction
S. Fujita1), A. E. Mikesky2), Y. Sato3) and T. Abe1)
1) Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo
2) School of Physical Education and Tourism Management, Indiana University-Purdue University
3) Depertment of Ischemic Circulatory Physiology, The University of Tokyo
(Accepted January 28, 2008)
Abstract
Low-intensity resistance exercise combined with blood flow restriction has been shown to elicit hormonal and neuromuscular responses similar to those with high-intensity resistance exercise. However, muscle fatigue characteristics during resistance exercise with restricted blood flow have not been clarified. Therefore, we measured maximal voluntary torque values during isokinetic concentric leg extensions across 30 repetitions at 180°/s either with blood flow restriction (BFR) or without restriction (CON) in eight healthy adults. The exercise was performed at the rate of either 30 repetitions/minute (BFR30 and CON30) or 15 repetitions/minute (BFR15 and CON15) designed to allow different rest intervals between contractions. Muscle fatigue was quantified by two methods: slope of peak isokinetic torque values through the 30th repetition and percent decrease in force from the first 5 repetitions to the last 5 repetitions. At the rate of 30 repetitions/minute, both fatigue rates were similar between BFR and control group. On the contrary, both fatigue rates were significantly higher in BFR15 group than the CON15 group (p<0.05). The results indicate that during resistance exercise performed with longer inter-repetition rest intervals, blood flow restriction is more effective at inducing muscle fatigue and thus may increase the training response. Furthermore, inter-repetition rest intervals of less than 3.5 seconds can increase fatigue level regardless of muscle perfusion.
The Effects Of Differing Thigh Composition On Tissue Oxygenation Of The Quadriceps Following Vascular Restriction: 1822: Board #172 May 27 2:00 PM - 3:30 PM
Escobar, Jacqueline; Karabulut, Murat; Abe, Takashi; Sato, Yoshiaki; Bemben, Michael G. FACSM
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Author Information
1University of Texas at Brownsville, Brownsville, TX. 2University of Tokyo, Chiba, Japan. 3University of Tokyo, Tokyo, Japan. 4University of Oklahoma, Norman, OK.
(No relationships reported)
KAATSU is a new training technique which can utilize different initial pressures (ranging between 30 and 70 mmHg) prior to an incremental increase in pressure to restrict blood flow during exercise, however it has not been investigated if tissue oxygenation would be affected by the composition of the restricted limb.
PURPOSE: To examine the effects of subcutaneous fat and lean muscle mass on tissue oxygenation of the quadriceps muscles while using three different initial restriction pressures.
METHODS: Six healthy males (30.0±4.6 years) had their thigh size measured by circumferences, skinfolds, ultrasound, and dual energy x-ray absorptiometry (DXA) to determine volume and thickness of subcutaneous fat and regional bone free muscle mass. Following skin preparation, Near-Infrared Spectroscopy was placed over the mid-thigh to measure tissue oxygenation. The KAATSU belt was placed on the upper most portion of the thigh, and participants then experienced initial pressures of 30, 50, and 70 mmHg in random order on three separate days. Tissue oxygenation was recorded at rest (lying down) once initial pressure was set, then following six pressures (120, 140, 160, 180, 200, and 220 mmHg) were sequentially applied to restrict blood flow for 4-min with 2-min rest periods between trials without pressure. Pearson correlations explored relationships between variables with the level of significance set at 0.05.
RESULTS: Correlations between leg LBM and tissue oxygenation were significant and strong (r= 0.87 to 0.97) when initial pressure was set at 70 mmHg, however, there was only minimal association with subcutaneous fat. A significant positive correlation was detected between tissue oxygenation and thigh circumference at 70 mmHg (r= 0.85), however when the restriction pressure was increased, correlations became were non-significant and moderate in nature (r= 0.58 to 0.78). Tissue oxygenation was generally inversely or weakly related to thigh circumference (r= -0.62 to 0.32), subcutaneous fat (r= -0.53 to 0.41), and leg LBM (r= -0.45 to 0.34) when initial pressures were set at 30 and 50 mmHg.
CONCLUSIONS: The findings indicated that when using the highest initial restrictive pressure of 70 mmHg, tissue oxygenation was positively correlated with leg muscle mass due to greater blood pooling.
Increased muscle volume and strength following six days of low-intensity resistance training with restricted muscle blood flow
T. Fujita1), W. F. Brechue2), K. Kurita3), Y. Sato1) and T. Abe1)
1) Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo
2) Center for Physical Development Excellence, United State Military Academy
3) Physical Conditioning Production
(Accepted June 17, 2008)
Abstract
Traditional high-intensity resistance training performed 2-3 times per week induces muscle hypertrophy, at least, in 5 weeks (i.e. 10-15 training sessions). To examine the effect of a higher training frequency (12 sessions in 6 days), healthy young men performed low-intensity resistance training with (n=8, LIT-BFR) and without (n=8, LIT-CON) leg blood flow restriction with cuff inflation (BFR) twice per day for 6 days. Training involved 4 sets of knee extension exercise (75 total contractions) at 20% 1-RM. Significant muscle hypertrophy was observed only in the LIT-BFR group as estimated muscle-bone cross-sectional area (CSA) (2.4%), MRI-measured mid-thigh quadriceps muscle CSA (3.5%) and quadriceps muscle volume (3.0%) increased. The resulting hypertrophic potential (% change in muscle size divided by number of training sessions; ?0.3% per session) is similar to previously reported traditional high-intensity training (0.1 to 0.5% per session). Improved 1-RM knee extension strength (6.7%) following LIT-BFR training was accounted for by increased muscle mass as relative strength (1-RM/CSA) did not change. There was no apparent muscle damage associated with the exercise training as blood levels of creatine kinase, myoglobin, and interleukin-6 remained unchanged throughout the training period in both training groups. A single bout of training exercise with and without BFR produced no signs of blood clotting as plasma thrombin-antithrombin complex, prothrombin fragment 1,2 and D-dimer were unchanged. In conclusion, changes in muscle mass and strength following 6-day (12 sessions) of low-intensity resistance training requires BFR to produce responses comparable to the effect of several weeks of high-intensity resistance training.
Effects of Exercise Load and Blood-Flow Restriction on Skeletal Muscle Function
COOK, SUMMER B.; CLARK, BRIAN C.; PLOUTZ-SNYDER, LORI L.
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Abstract
Resistance training at low loads with blood flow restriction (BFR) (also known as Kaatsu) has been shown to stimulate increases in muscle size and strength. It is unclear how occlusion pressure, exercise intensity, and occlusion duration interact, or which combination of these factors results in the most potent muscle stimulus.
Purpose: To determine the effect of eight BFR protocols on muscle fatigue (decrement in maximal voluntary contraction (MVC) after the performance of exercise), and to compare the decrement in MVC with the currently recommended resistance exercise intensity (~80% MVC).
Methods: During five test sessions, 21 subjects (14 males and 7 females, 27.7 ± 4.9 yr) completed nine protocols, each consisting of three sets of knee extensions (KE) to failure. One protocol was high-load (HL) exercise (80% MVC) with no BFR, and the other eight were BFR at varying levels of contraction intensity (20 or 40% MVC), occlusion pressure (partial (~160 mm Hg) or complete (~300 mm Hg)), and occlusion duration (off during the rest between sets or continuously applied). To evaluate each protocol, MVC were performed before and after exercise, and the decrement in force was calculated.
Results: Three sets of KE at 20% MVC with continuous partial occlusion (20%ConPar) resulted in a greater decrement in MVC compared with HL (31 vs 19%, P = 0.001). None of the other BFR protocols were different from the HL protocol, nor were they different from 20%ConPar (P > 0.05).
Conclusion: All BFR protocols elicited at least as much fatigue as HL, even though lower loads were used. The 20%ConPar protocol was the only one that elicited significantly more fatigue than HL. Future research should evaluate protocol training effectiveness and overall safety of BFR exercise.
Effects of Vascular Occlusion on Muscular Endurance in Dynamic Knee Extension Exercise At Different Submaximal Loads
WERNBOM, MATHIAS; AUGUSTSSON, JESPER; THOMEÉ, ROLAND
Abstract
Strength training with low load under conditions of vascular occlusion has been proposed as an alternative to heavy-resistance exercise in the rehabilitation setting, when large forces acting upon the musculoskeletal system are unwanted. Little is known, however, about the relative intensity at which occlusion of blood flow significantly reduces dynamic muscular endurance and, hence, when it may increase the training effect. The purpose of this study was to investigate endurance during dynamic knee extension at different loads with and without cuff occlusion. Sixteen subjects (20-45 years of age) with strength-training experience were recruited. At 4 test sessions, the subjects performed unilateral knee extensions to failure with and without a pressure cuff around the thigh at 20, 30, 40, and 50% of their 1 repetition maximum (1RM). The pressure cuff was inflated to 200 mm Hg during exercise with occlusion. Significant differences in the number of repetitions performed were found between occluded and nonoccluded conditions for loads of 20, 30, and 40% of 1RM (p < 0.01) but not for the 50% load (p = 0.465). Thus, the application of a pressure cuff around the thigh appears to reduce dynamic knee extension endurance more at a low load than at a moderate load. These results may have implications regarding when it could be useful to apply a tourniquet in order to increase the rate of fatigue and perhaps also the resulting training effect. However, the short- and long-term safety of training under ischemic conditions needs to be addressed in both healthy and less healthy populations. Furthermore, the high acute pain ratings and the delayed-onset muscle soreness associated with this type of training may limit its potential use to highly motivated individuals.
The effects of low-intensity resistance training with vascular restriction on leg muscle strength in older men
Journal European Journal of Applied Physiology
Publisher Springer Berlin / Heidelberg
ISSN 1439-6319 (Print) 1439-6327 (Online)
Issue Volume 108, Number 1 / January, 2010
Category Original Article
DOI 10.1007/s00421-009-1204-5
Pages 147-155
Subject Collection Biomedical and Life Sciences
SpringerLink Date Thursday, September 17, 2009
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Original Article
The effects of low-intensity resistance training with vascular restriction on leg muscle strength in older men
Murat Karabulut1 Contact Information, Takashi Abe3, Yoshiaki Sato4 and Michael G. Bemben2
(1) Department of Health and Human Performance, University of Texas at Brownsville/Texas Southmost College, 80 Fort Brown, Brownsville, TX 78520, USA
(2) Department of Health and Exercise Science, University of Oklahoma, Norman, OK, USA
(3) Graduate School of Frontier Sciences, University of Tokyo, Chiba, Japan
(4) Department of Ischemic Circulatory Physiology, University of Tokyo, Tokyo, Japan
Accepted: 10 September 2009 Published online: 18 September 2009
Communicated by Jean-René Lacour, Susan A. Ward.
Abstract The purpose of this study was to investigate and compare the effects of two types of resistance training protocols on the adaptation of skeletal muscle strength in older men. Thirty-seven healthy male subjects (50–64 years) participated in this study. Subjects were assigned to one of three groups: high-intensity (80% 1-RM) resistance training (RT80); low-intensity (20% 1-RM) resistance training with vascular restriction (VR-RT20); and a control group (CON) that performed no exercise. Subjects in both exercise groups performed three upper body (at 80% 1-RM) and two lower body exercises either with (20% 1-RM) or without (80% 1-RM) vascular restriction three times a week for 6 weeks. As expected, the RT80 and VR-RT20 groups had significantly (p < 0.01) greater strength increases in all upper body and leg press exercises compared with CON, however, absolute strength gains for the RT80 and VR-RT20 groups were similar (p > 0.05). It should be noted that the percentage increase in leg extension strength for the RT80 group was significantly greater than that for both the VR-RT20 (p < 0.05) and CON groups (p < 0.01), while the percentage increase in leg extension strength for the VR-RT20 group was significantly (p < 0.01) greater than that for the CON. The findings suggested that leg muscle strength improves with the low-load vascular restriction training and the VR-RT20 training protocol was almost as effective as the RT80 training protocol for increasing muscular strength in older men.
Neuromuscular fatigue following low-intensity dynamic exercise with externally applied vascular restriction
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Murat Karabuluta, Corresponding Author Contact Information, E-mail The Corresponding Author, Joel T. Cramerb, Takashi Abec, Yoshiaki Satod and Michael G. Bembenb
aDepartment of Health and Human Performance, University of Texas at Brownsville/Texas Southmost College, TX, USA
bDepartment of Health and Exercise Science, University of Oklahoma Norman, OK, USA
cGraduate School of Frontier Sciences, University of Tokyo, Chiba, Japan
dDepartment of Ischemic Circulatory Physiology, University of Tokyo, Tokyo, Japan
Received 13 January 2009;
revised 23 June 2009;
accepted 25 June 2009.
Available online 28 July 2009.
Abstract
This study investigated neuromuscular fatigue following low-intensity resistance exercise with vascular restriction (VR) and without vascular restriction (control, CON). Fourteen males participated in two experimental trials (VR and CON) each separated by 48 h. Each participant performed two isometric maximum voluntary contractions (MVCs) before and after five sets of 20 dynamic constant external resistance leg extension exercises (DCER-EX) at 20% of one-repetition maximum (1-RM). The participants were asked to lift (1.5 s) and lower (1.5 s) the load at a constant velocity. Surface electromyography (EMG) was recorded from the vastus lateralis during MVC and DCER-EX. Twitch interpolation was used to assess the percent of maximal voluntary activation (%VA) during the MVC. During performing five sets of 20 DCER-EX, the increases (p < 0.05) in EMG amplitude and decreases (p < 0.05) in EMG mean power frequency were similar for both VR and CON. However, there were significant differences between VR and CON for MVC force, %VA, and potentiated twitch force and significant interactions for EMG amplitude. VR decreased MVC force, %VA, potentiated twitch force, and EMG amplitude more than CON. Our findings suggest that the VR-induced fatigue may have been due to a combination of peripheral (decreases in potentiated twitch) and central (decreases in %VA and EMG amplitude) fatigue.
Cross-Transfer Effects of Resistance Training with Blood Flow Restriction
MADARAME, HARUHIKO; NEYA, MITSUO; OCHI, EISUKE; NAKAZATO, KOICHI; SATO, YOSHIAKI; ISHII, NAOKATA
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Abstract
Purpose: This study investigated whether muscle hypertrophy-promoting effects are cross-transferred in resistance training with blood flow restriction, which has been shown to evoke strong endocrine activation.
Methods: Fifteen untrained men were randomly assigned into the occlusive training group (OCC, N = 8) and the normal training group (NOR, N = 7). Both groups performed the same unilateral arm exercise (arm curl) at 50% of one-repetition maximum (1RM) without occlusion (three sets, 10 repetitions). Either the dominant or nondominant arm was randomly chosen to be trained (OCC-T, NOR-T) or to serve as a control (OCC-C, NOR-C). After the arm exercise, OCC performed leg exercise with blood flow restriction (30% of 1RM, three sets, 15-30 repetitions), whereas NOR performed the same leg exercise without occlusion. The training session was performed twice a week for 10 wk. In a separate set of experiments, acute changes in blood hormone concentrations were measured after the same leg exercises with (N = 5) and without (N = 5) occlusion.
Results: Cross-sectional area (CSA) and isometric torque of elbow flexor muscles increased significantly in OCC-T, whereas no significant changes were observed in OCC-C, NOR-T, and NOR-C. CSA and isometric torque of thigh muscles increased significantly in OCC, whereas no significant changes were observed in NOR. Noradrenaline concentration showed a significantly larger increase after leg exercise with occlusion than after exercises without occlusion, though growth hormone and testosterone concentrations did not show significant differences between these two types of exercises.
Conclusion: The results indicate that low-intensity resistance training increases muscular size and strength when combined with resistance exercise with blood flow restriction for other muscle groups. It was suggested that any circulating factor(s) was involved in this remote effect of exercise on muscular size.
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Effect of resistance exercise training combined with relatively low vascular occlusion
Journal of Science and Medicine in Sport, Volume 12, Issue 1, Pages 107-112
T. Sumide, K. Sakuraba, K. Sawaki, H. Ohmura, Y. Tamura
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Abstract
Previous studies have demonstrated that a low-intensity resistance exercise, combined with vascular occlusion, results in a marked increase in muscular size and strength. We investigated the optimal pressure for reduction of muscle blood flow with resistance exercise to increase the muscular strength and endurance. Twenty-one subjects were randomly divided into four groups by the different application of vascular occlusion pressure at the proximal of thigh: without any pressure (0-pressure group), with a pressure of 50mmHg (50-pressure group), with a pressure of 150mmHg (150-pressure group), and with a pressure of 250mmHg (250-pressure group). The isokinetic muscle strength at angular velocities of 60 and 180°/s, total muscle work, and the cross-sectional knee extensor muscle area were assessed before and after exercise. Exercise was performed three times a week over an 8-week period at an intensity of approximately 20% of one-repetition maximum for straight leg raising and hip joint adduction and maximum force for abduction training. A significant increase in strength at 180°/s was noted after exercise in all subjects who exercised under vascular occlusion. Total muscle work increased significantly in the 50- and 150-pressure groups (P<0.05, P<0.01, respectively). There was no significant increase in cross-sectional knee extensor muscle area in any groups. In conclusion, resistance exercise with relatively low vascular occlusion pressure is potentially useful to increase muscle strength and endurance without discomfort.
Venous blood gas and metabolite response to low-intensity muscle contractions with external limb compression
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Tomohiro Yasudaa, b, Corresponding Author Contact Information, E-mail The Corresponding Author, Takashi Abeb, William F. Brechuec, Haruko Iidaa, Haruhito Takanoa, Kentaro Meguroa, Miwa Kuranoa, Satoshi Fujitab and Toshiaki Nakajimaa
a Department of Ischemic Circulatory Physiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
b Institute of Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
c Center for Physical Development Excellence, United States Military Academy, West Point, New York, United States
Received 12 September 2009;
accepted 21 January 2010.
Available online 4 March 2010.
Abstract
The effect of low-intensity resistance exercise with external limb compression (100 [EC100] and 160 [EC160] mm Hg) on limb blood flow and venous blood gas-metabolite response was investigated and compared with that of high-intensity resistance exercise (no external compression). Unilateral elbow flexion muscle contractions were performed at 20% (75 repetitions, 4 sets, 30-second rest intervals) and 70% of 1-repetition maximum (1-RM; 3 sets, each set was until failure, 3-minute rest intervals). Precontraction brachial arterial blood flow (Doppler ultrasound) was reduced with EC100 or EC160 (56% and 39% of baseline value, respectively) compared with no external compression (control). At 20% 1-RM, brachial arterial blood flow increased after contractions performed with EC160 (190%), but not with the others. Decreases in venous oxygen partial pressure (PvO2) and venous oxygen saturation (SvO2) were greater during EC100 and EC160 than control (mean [SE]: PvO2, 28 [3] vs 26 [2] vs 33 [2] mm Hg; SvO2, 41% [5%] vs 34% [4%] vs 52% [5%], respectively). Changes in venous pH (pHv), venous carbon dioxide partial pressure (PvCO2), and venous lactate concentration ([L?]v) were greater with EC160 than EC100 and/or control (pHv, 7.19 [0.01] vs 7.25 [0.01] vs 7.27 [0.02]; PvCO2, 72 [3] vs 64 [2] vs 60 [3] mm Hg; [L?]v, 5.4 [0.6] vs 3.7 [0.4] vs 3.0 [0.4] mmol/L, respectively). Seventy percent 1-RM contractions resulted in greater changes in pHv (7.14 [0.02]), PvCO2 (91 [5] mm Hg), and [L?]v (7.0 [0.5] mmol/L) than EC100 and EC160, but PvO2 (30 [4] mm Hg) and SvO2 (40% [3%]) were similar. In conclusion, changes in pHv, PvCO2, and [L?]v, but not in PvO2 and SvO2, are sensitive to changes in relative, “internal” intensity of low-intensity muscle contractions caused by reduced blood flow (EC160) or high-intensity muscle contractions. Given the magnitude of the changes in pHv, PvCO2, and [L?]v, it appears plausible that they may be involved in stimulating the observed increase in muscle activation via group III and IV afferents.
The Use of Occlusion Training to Produce Muscle Hypertrophy
Loenneke, Jeremy Paul BS; Pujol, Thomas Joseph EdD, CSCS
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Abstract
LOW-INTENSITY OCCLUSION (50-100 MM HG) TRAINING PROVIDES A UNIQUE BENEFICIAL TRAINING MODE FOR PROMOTING MUSCLE HYPERTROPHY. TRAINING AT INTENSITIES AS LOW AS 20% 1 REPETITION MAXIMUM WITH MODERATE VASCULAR OCCLUSION RESULTS IN MUSCLE HYPERTROPHY IN AS LITTLE AS 3 WEEKS. A TYPICAL EXERCISE PRESCRIPTION CALLS FOR 3 TO 5 SETS TO VOLITIONAL FATIGUE WITH SHORT REST PERIODS. THE METABOLIC BUILDUP CAUSES POSITIVE PHYSIOLOGIC REACTIONS, SPECIFICALLY A RISE IN GROWTH HORMONE THAT IS HIGHER THAN LEVELS FOUND WITH HIGHER INTENSITIES. OCCLUSION TRAINING IS APPLICABLE FOR THOSE WHO ARE UNABLE TO SUSTAIN HIGH LOADS DUE TO JOINT PAIN, POSTOPERATIVE PATIENTS, CARDIAC REHABILITATION, ATHLETES WHO ARE UNLOADING, AND ASTRONAUTS.
Effects of Handgrip Training With Venous Restriction on Brachial Artery Vasodilation
Credeur, Daniel P.; Hollis, Brandon C.; Welsch, Michael A.
Published Ahead-of-Print
Abstract
Previous studies have shown that resistance training with restricted venous blood flow (Kaatsu) results in significant strength gains and muscle hypertrophy. However, few studies have examined the concurrent vascular responses following restrictive venous blood flow training protocols.
Purpose: To examine the effects of 4 weeks of handgrip exercise training, with and without venous restriction, on handgrip strength and brachial artery flow mediated dilation (BAFMD).
Methods: Twelve participants (age=22+/-1yr; male = 5, female = 7), completed 4 weeks of bilateral handgrip exercise training (Duration: 20 min; Intensity: 60% of the MVC; Cadence: 15 grips*min-:1; Frequency: 3 sessions*week-1). During each session venous blood flow was restricted in one arm (Experimental arm = EXP) using a pneumatic cuff placed 4 cm proximal to the antecubital fossa, and inflated to 80 mmHg for the duration of each exercise session. The EXP and control (CON) arm were randomly selected. Handgrip strength was measured using a hydraulic hand dynamometer. Brachial diameters and blood velocity profiles were assessed, using Doppler ultrasonography, before and after 5 min of forearm occlusion (200 mmHg), prior to and at the end of 4 weeks exercise.
Results: Following exercise training, handgrip strength increased 8.32% (p=0.05) in the CON arm and 16.17% (p=0.05) in the EXP arm. BAFMD increased 24.19% (p=0.0001) in the CON arm, and decreased 30.36% (p=0.0001) in the EXP arm.
Conclusion: The data indicate handgrip training combined with venous restriction results in superior strength gains, but reduced BAFMD compared to the non-restricted arm.
Acute vascular occlusion in horses: effects on skeletal muscle size and blood flow
T Abea1 c1, CF Kearnsa2, HC Manso Filhoa3, Y Satoa4, M Sleepera5 and KH McKeevera3
a1 Department of Exercise and Sport Science, Tokyo Metropolitan University, 1-1 Minami-Ohsawa, Hachioji, Tokyo, 192-0397, Japan
a2 Cardiovascular/Endocrine Biology, Schering-Plough Research Institute, Kenilworth, NJ, USA
a3 Equine Science Center, Department of Animal Sciences, Cook College, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA
a4 Sato Institute for Rehabilitation and Fitness, Fuchu, Tokyo, Japan
a5 Ryan Veterinary Hospital, University of Pennsylvania, Philadelphia, PA, USA
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Abstract
The purpose of this study was to demonstrate whether acute vascular occlusion was safe and if it would result in changes to limb muscle size in horses. Six healthy, unfit Standardbred mares were used. Horses (standing at rest) wore an occlusion cuff at the most proximal position of the left forelimb. The right forelimb was used as control. An occlusion pressure of 200 mmHg was set for 5 min followed by a 2 min recovery. Three sets of occlusions were given to each horse. Muscle thickness was measured using B-mode ultrasound. The circumference of the forelimb and first phalanx was measured using a flexible tape measure. Pulsed-wave Doppler was performed on the radialis artery with a 5–10 MHz mechanical transducer at baseline and at each occlusion. Peak flow velocity (PFV) and the flow velocity integral (FVI) were measured each time. Mid-forelimb, but not first phalanx, girth was increased (P<0.05) in the occluded but not in the control leg following occlusion. Extensor and flexor muscle thickness was increased (P<0.05) in the occluded but not in the control leg. There were no changes (P>0.05) in PFV or FVI at any measurement time point. Acute vascular occlusion may be a suitable and safe model for studying muscle hypertrophy in horses.
Increase in calf post-occlusive blood flow and strength following short-term resistance exercise training with blood flow restriction in young women
Journal European Journal of Applied Physiology
Publisher Springer Berlin / Heidelberg
ISSN 1439-6319 (Print) 1439-6327 (Online)
Issue Volume 108, Number 5 / March, 2010
Category Original Article
DOI 10.1007/s00421-009-1309-x
Pages 1025-1033
Subject Collection Biomedical and Life Sciences
SpringerLink Date Friday, December 11, 2009
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Original Article
Increase in calf post-occlusive blood flow and strength following short-term resistance exercise training with blood flow restriction in young women
Stephen D. Patterson1 and Richard. A. Ferguson1 Contact Information
(1) School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK
Accepted: 23 November 2009 Published online: 11 December 2009
Communicated by Susan Ward.
Abstract
The response of calf muscle strength, resting (R bf) and post-occlusive (PObf) blood flow were investigated following 4 weeks resistance training with and without blood flow restriction in a matched leg design. Sixteen untrained females performed unilateral plantar-flexion low-load resistance training (LLRT) at either 25% (n = 8) or 50% (n = 8) one-repetition maximum (1 RM). One limb was trained with unrestricted blood flow whilst in the other limb blood flow was restricted with the use of a pressure applied cuff above the knee (110 mmHg). Regardless of the training load, peak PObf, measured using venous occlusion plethysmography increased when LLRT was performed with blood flow restriction compared to no change following LLRT with unrestricted blood flow. A significant increase (P < 0.05) in the area under the blood time–flow curve was also observed following LLRT with blood flow restriction when compared LLRT with unrestricted blood flow. No changes were observed in R bf between groups following training. Maximal dynamic strength (1 RM), maximal voluntary contraction and isokinetic strength at 0.52 and 1.05 rad s?1 also increased (P < 0.05) by a greater extent following resistance training with blood flow restriction. Moreover, 1 RM increased to a greater extent following training at 50% 1 RM compared to 25% 1 RM. These results suggest that 4 weeks LLRT with blood flow restriction provides a greater stimulus to increase peak PObf as well as strength parameters than LLRT with unrestricted blood flow.
Changes of Compound Muscle Action Potential after Low-Intensity Exercise with Transient Restriction of Blood Flow: a Randomized, Placebo-Controlled Trial
Laurentius Jongsoon Kim1)
1) Department of Physical Therapy, College of Health Sciences, Catholic University of Pusan
(This article was accepted July 24, 2009)
Abstract. [Purpose] The purpose of this study was to investigate the mechanism of muscular force improvement after low-intensity exercise with transient restriction of blood flow using compound muscle action potential (CMAP) analysis. [Subjects] Thirty healthy subjects in their 20s (mean age=21.73 years) were randomly assigned to an experimental group (EG) and a placebo control group (PG); each group had 15 subjects. [Methods] CMAP was analyzed by measuring terminal latency and amplitude using a motor nerve conduction velocity test. For Baseline 1, supramaximal electrical stimulation was applied to the median nerves of the EG and PG to obtain CMAP at the abductor pollicis brevis. For Baseline 2, the intensity of the electrical stimulation was decreased to a level at which the CMAP amplitude was about a third (1/3) of the CMAP amplitude obtained by supramaximal electrical stimulation. In the first test, CMAP was obtained under the same conditions as Baseline 2 after low-intensity thumb abduction exercises were performed at subjects' own pace for one minute. EG had blood flow restricted by a sphygmomanometer cuff, but PG did not. In the retest, CMAP was obtained under the same conditions as Baseline 2, one minute after the removal of the sphygmomanometer cuff immediately after the first test. [Results] PG did not show significant changes in CMAP, whereas EG showed a significant increase in CMAP amplitude, signifying that more muscle fibers were recruited. [Conclusion] This study found that low-intensity exercise with transient restriction of blood flow recruited more muscle fibers than low-intensity exercise without transient restriction of blood flow.
Growth hormone and muscle function responses to skeletal muscle ischemia
Joseph R. Pierce, Brian C. Clark, Lori L. Ploutz-Snyder, and Jill A. Kanaley
Department of Exercise Science, Syracuse University, Syracuse, New York
Submitted 25 May 2006 ; accepted in final form 21 July 2006
We examined the effects of ischemia (ISC) alone and with low-intensity exercise (ISC+EX) on growth hormone (GH) and muscle function responses. Nine men (22 ± 0.7 yr) completed 3 study days: an ISC day (thigh cuff inflated five times, 5 min on, 3 min off), an ISC+EX day [knee extension at 20% maximal voluntary contraction (MVC) with ISC], and a control day. MVCs and submaximal contraction tasks (15 and 30% MVC) were performed before and following the perturbations. Surface electromyogram signals were collected from thigh muscles and analyzed for median frequency and root mean square alterations. Blood samples were collected every 10 min (190 min total) and analyzed for GH concentrations. Peak GH concentrations and GH area under the curve were highest (P < 0.01) on the ISC+EX day (7.5 µg/l and 432 µg·l–1·min–1, respectively) compared with the ISC (0.9 µg/l and 76.4 µg·l–1·min–1), and CON (1.1 µg/l and 83.8 µg·l–1·min–1) days. A greater GH pulse amplitude, mass/pulse, and production rate were also observed on the ISC+EX day (P < 0.05). Following the intervention, force production decreased on the ISC and ISC+EX days by 16.1 and 55.8%, respectively, and did not return to baseline values within 5 min of recovery. During the submaximal contractions, median frequency shifted to lower frequencies for most of the muscles examined, and root mean square electromyogram was consistently elevated for ISC+EX day. In conclusion, ISC coupled with resistance exercise acutely increases GH levels and reduces MVC, whereas ISC alone decreases force capacity, without alterations in GH levels.
Changes In Tissue Oxygenation And Muscular Function In Response To Vascular Restriction: 1826: Board #176 May 27 2:00 PM - 3:30 PM
Karabulut, Murat; Wittenburg, David; Sato, Yoshiaki; Abe, Takashi; Bemben, Michael G. FACSM
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Author Information
1University of Texas at Brownsville, Brownsville, TX. 2University of Tokyo, Tokyo, Japan. 3University of Tokyo, Chiba, Japan. 4University of Oklahoma, Norman, OK.
Email: murat.karabulut@utb.edu
(No relationships reported)
A single bout of low-intensity resistance exercise (20% 1-RM) combined with vascular restriction (i.e., KAATSU training) takes about 3-5 min to elicit a fatigue response. It has been reported that vascular restriction alone has been used to prevent atrophy, therefore, it would be important to determine how different pressures of blood flow restriction, applied for similar durations, can alter the metabolic demands of skeletal muscle and change muscle function.
PURPOSE: To examine the effects of altering vascular restriction pressure of the leg on percent voluntary activation (PVA) of the medial gastrocnemius (MG), tissue oxygenation of the calf muscles, and the electromyographic (EMG) and mechanomyographic (MMG) responses of MG.
METHODS: Thirteen young healthy males (Mean ± SD age = 24.6 ± 5.3 years; height = 175.7 ± 5.3 cm; weight = 77.7 ± 7.5 kg) performed one maximal isometric voluntary contraction (MVC) of the right plantar flexors at baseline. Then, following 2-min rest, six different pressures (40, 120, 160, 180, 200, 250 mmHg) were sequentially applied to restrict blood flow for 4-min with 2-min rest periods between trials with no pressure. At the end of each pressure setting, a MVC was performed. PVA, EMG and MMG responses were assessed during the twitch interpolation technique and tissue oxygenation was measured by near infrared spectroscopy. A repeated measures ANOVA was used to determine the main effects for trial with the level of significance set at 0.05.
RESULTS: The results showed that tissue oxygenation significantly decreased with increasing pressures (p<0.05, ranged from 81% to 46%). However, there were no significant changes in MVC torque, PVA, EMG amplitude, EMG mean power frequency (MPF), MMG amplitude, and MMG MPF.
CONCLUSIONS: Four minute periods of restricting blood flow to the lower limb with pressures up to 250 mmHg were not sufficient to induce a significant metabolic challenge that would cause changes in muscular function.
Venous Blood Changes with Low-Intensity Muscle Contractions and Blood Flow Restriction: 1989: Board #153 May 29 2:00 PM - 3:30 PM
Yasuda, Tomohiro; Abe, Takashi; Kurano, Miwa; Takano, Haruhito; Meguro, Kentaro; Brechue, William F. FACSM; Morita, Toshihiro; Sato, Yoshiaki; Nakajima, Toshiaki
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1The University of Tokyo, Tokyo, Japan. 2The University of Tokyo, Kashiwa, Japan. 3United States Military Academy, West Point, NY.
Email: yasuda-tomohiro@umin.ac.jp
(No relationships reported)
Work output during repetitive low-intensity muscle contractions is presumably maintained by increased motor unit recruitment (increased EMG activity) during restricted blood flow. Interestingly, the increased muscle activation is associated with an increased oxygen uptake (Vo2); an unexpected finding given the same external work and reduced muscle blood flow.
PURPOSE: To investigate changes in venous blood metabolites and gases during repetitive muscle contractions with restricted blood flow.
METHODS: Six male volunteers performed 3 trials (separated by 1-week) of unilateral elbow flexion muscle contractions (20% of 1-RM; 30 repetitive contractions then 3 sets of 15 contractions, 30 sec rest between sets). Contractions were performed with unrestricted blood flow (C) or two levels of blood flow restriction using a KAATSU belt; a specially designed elastic cuff placed at the most proximal position of the upper arm and inflated to either 100 (K100) or 160 (K160) mmHg to restrict blood flow. Venous blood was collected prior to contractions and following the 30 repetitive contractions and the last set of 15 contractions; (an indwelling catheter inserted in the brachial vein below the cuff). Venous blood was analyzed using a blood gas analyzer (Instrumentation Laboratory, Japan).
RESULTS: Oxygen saturation decreased with contractions in all trials (P<0.05) with K160 (33% and 34%, respectively) being greater than K100 (41% and 42%, respectively) and both greater than C (67% and 56%, respectively). Changes in venous blood pH and PCO2 were greater in K160 than K100 and C. Venous PO2 decreased similarly in K160 and K100, significantly less than C. Hematocrit and [glucose] were similar in all trials while [lactate] was greater (P<0.05) in K160 (4.4 and 5.6 mmol/L, respectively) than K100 (3.2 and 3.6 mmol/L, respectively) and C (2.5 and 2.9 mmol/L, respectively).
CONCLUSION: The significant reduction in oxygen saturation supports the previously observed increase in VO2 during blood flow restriction. The basis for the greater lactate concentration is unknown; either increased production or reduced removal. These data appear to support the conclusion that energy supply is paradoxically increased during low-intensity muscle contractions with restricted blood flow, likely associated with increased muscle activation.
What phenomena do occur in blood flow-restricted muscle?
S. Kawada1)
1) Institute of Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo
Abstract
Oxygen is an essential molecule for all cellular activities including growth. Either excessive or deficient oxygen supply to cells induces the various responses of the cells. In the field of pathophysiology, effects of blood flow restriction on various organs have been studied for the past ?130 years. Subsequently, the roles of oxygen at subcellular level have been studied in vitro. Although a number of studies show that a low-intensity exercise (20?50% of one repetition maximum) with a moderate tourniquet restriction of blood flow results in increases in muscular strength and size, the mechanisms for this muscular adaptation remain unclear. In particular, it is uncertain whether the low-intensity exercise with blood flow restriction using a tourniquet causes the hypoxia or hyperoxia in the muscle, and then what signals leading to muscular hypertrophy are activated inside and/ or outside the cells. Also, it is not well understood what side effects occur in addition to conferring the benefits of strength gains. The review summarizes recent studies on the muscular adaptations to oxygen environment and discusses the mechanisms that may be involved in the resistance exercise with restricted blood flow.
Time under Tension and Blood Lactate Response during Four Different Resistance Training Methods
Paulo Gentil1), Elke Oliveira1) and Martim Bottaro2)
1) College of Health Sciences, University of Brasilia
2) College of Physical Education and Exercise Science, University of Brasilia
Abstract:
Mechanical stimuli have often been suggested to be the major determinant of resistance training adaptations; however, some studies suggested that metabolic changes also play an important role in the gains of muscle size and strength. Several resistance training methods (RTM) have been employed with the purpose of manipulating mechanical and metabolic stimuli; however, information about their physiological effects are scarce. The objective of this study was to compare the time under tension (TUT) and blood lactate responses among four different RTM reported in the literature. The four RTM were performed in a knee extension machine at 10 repetition maximum (RM) load by 12 recreationally trained young men. The RTM tested were: 10RM, super-slow (SL—subjects performed one 60-second repetition with 30 seconds for eccentric and 30 seconds for concentric phase), functional isometrics (FI—in each repetition, a five-second maximal isometric contraction was executed with the knees fully extended) and adapted vascular occlusion (VO—subjects performed a 20-second maximal isometric contraction with the knees fully extended and immediately proceeded to normal isoinertial lifts). According to the results, all RTM produced significant increases in blood lactate levels. However, blood lactate responses during FI (4.48±1.57 mM) and VO (4.23±1.66 mM) methods were higher than the SL method (3.41±1.14 mM). The TUT for SL (60 s), FI (56.33±6.46 s), and VO (53.08±4.76 s) methods were higher than TUT for 10RM (42.08±3.18 s). Additionally, TUT for the SL method was higher than TUT during the VO method. Therefore, the SL method may not be recommended if one wants to provide a high metabolic stimulus. The FI method appeared to be especially effective in promoting both type of stimuli.
Enhancement of cardiac autonomic nervous system activity by blood flow restriction in the human leg
N. Kiyohara1), T. Kimura1), T. Tanaka1) and T. Moritani1)
1) Laboratory of Applied Physiology, The Graduate School of Human and Environmental Studies, Kyoto University
(Accepted October 17, 2006)
Abstract
The purpose of this study is to develop a unique method to enhance autonomic nervous system (ANS) activity by means of experimental leg occlusion. The effects of blood flow restriction on the activities of the ANS during rest were investigated using a power spectral analysis of heart rate variability. Two patterns of occlusion were randomly assigned to healthy subjects: pattern A, 10 min of 1.4 times of systolic blood pressure; pattern B, 5 min of mean blood pressure followed by 5 min of 1.4 times of systolic blood pressure. Electrocardiogram, blood pressure and cardiac output were continuously monitored during rest and occlusion. During occlusion, cardiac output and stroke volume showed significant decreases, due to modulation of autonomic nervous activity. After releasing from occlusion without blood pooling (A), the high frequency component of R-R interval variability representing vagal activity showed a significant increase (P<0.05). However, soon after releasing, the ECG QTc interval temporally prolonged (P<0.05) and recovered gradually. Further investigation is recommended to determine blood flow occlusion safety on the cardiac depolarization-repolarization process. In conclusion, the results suggest that blood flow restriction has potential to be a useful method to stimulate the activity of autonomic nervous system, and especially to enhance parasympathetic nervous system activity.
Plasticity of the Muscle Proteome to Exercise at Altitude
To cite this article:
Martin Flueck. High Altitude Medicine & Biology. Summer 2009, 10(2): 183-193. doi:10.1089/ham.2008.1104.
Published in Volume: 10 Issue 2: June 25, 2009
Online Ahead of Print: June 11, 2009
Full Text: • PDF for printing (41,608.3 KB) • PDF w/ links (424.1 KB)
Martin Flueck
Institute for Biomedical Research into Human Movement and Health, Manchester Metropolitan University, Manchester, UK.
Address correspondence to:
Martin Flueck, PhD
Institute for Biomedical Research into Human Movement and Health
Manchester Metropolitan University
Oxford Road, Manchester, M15 6BH,
UK
E-mail:
Received December, 18, 2008
accepted in final form January 20, 2009
Abstract
Flueck, Martin. Plasticity of the muscle proteome to exercise at altitude. High Alt. Med. Biol. 10: 183–193, 2009.—The ascent of humans to the summits of the highest peaks on Earth initiated a spurt of explorations into the physiological consequences of physical activity at altitude. The past three decades have demonstrated that the resetting of respiratory and cardiovascular control with chronic exposure to altitudes above 4000m is accompanied by important structural–functional adjustments of skeletal muscle. The fully altitude-adapted phenotype preserves energy charge at reduced aerobic capacity through the promotion of anaerobic substrate flux and tighter metabolic control, often at the expense of muscle mass. In seeming contrast, intense physical activity at moderate hypoxia (2500 to 4000m) modifies this response in both low and high altitude natives through metabolic compensation by elevating local aerobic capacity and possibly preventing muscle fiber atrophy. The combined use of classical morphometry and contemporary proteomic technology provides a highly resolved picture of the temporal control of hypoxia-induced muscular adaptations. The muscle proteome signature identifies mitochondrial autophagy and protein degradation as prime adaptive mechanisms to passive altitude exposure and ascent to extreme altitude. Protein measures also explain the lactate paradox by a sparing of glycolytic enzymes from general muscle wasting. Enhanced mitochondrial and angiogenic protein expression in human muscle with exercise up to 4000m is related to the reduction in intramuscular oxygen content below 1% (8torr), when the master regulator of hypoxia-dependent gene expression, HIF-1?, is stabilized. Accordingly, it is proposed here that the catabolic consequences of chronic hypoxia exposure reflect the insufficient activation of hypoxia-sensitive signaling and the suppression of energy-consuming protein translation.
Effects of low-intensity resistance exercise with slow movement and tonic force generation on muscular function in young men
Michiya Tanimoto and Naokata Ishii
Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Meguro-ku, Tokyo, Japan
Submitted 22 June 2005 ; accepted in final form 1 December 2005
We investigated the acute and long-term effects of low-intensity resistance exercise (knee extension) with slow movement and tonic force generation on muscular size and strength. This type of exercise was expected to enhance the intramuscular hypoxic environment that might be a factor for muscular hypertrophy. Twenty-four healthy young men without experience of regular exercise training were assigned into three groups (n = 8 for each) and performed the following resistance exercise regimens: low-intensity [~50% of one-repetition maximum (1RM)] with slow movement and tonic force generation (3 s for eccentric and concentric actions, 1-s pause, and no relaxing phase; LST); high-intensity (~80% 1RM) with normal speed (1 s for concentric and eccentric actions, 1 s for relaxing; HN); low-intensity with normal speed (same intensity as for LST and same speed as for HN; LN). In LST and HN, the mean repetition maximum was 8RM. In LN, both intensity and amount of work were matched with those for LST. Each exercise session consisting of three sets was performed three times a week for 12 wk. In LST and HN, exercise training caused significant (P < 0.05) increases in cross-sectional area determined with MRI and isometric strength (maximal voluntary contraction) of the knee extensors, whereas no significant changes were seen in LN. Electromyographic and near-infrared spectroscopic analyses showed that one bout of LST causes sustained muscular activity and the largest muscle deoxygenation among the three types of exercise. The results suggest that intramuscular oxygen environment is important for exercise-induced muscular hypertrophy.
Increase in maximal oxygen uptake following 2-week walk training with blood flow occlusion in athletes
Journal European Journal of Applied Physiology
Publisher Springer Berlin / Heidelberg
ISSN 1439-6319 (Print) 1439-6327 (Online)
Category Original Article
DOI 10.1007/s00421-010-1377-y
Subject Collection Biomedical and Life Sciences
SpringerLink Date Sunday, February 21, 2010
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Original Article
Increase in maximal oxygen uptake following 2-week walk training with blood flow occlusion in athletes
Saejong Park1, Jong Kyung Kim2, Hyun Min Choi2, Hyun Gook Kim2, Matthew D. Beekley3 and Hosung Nho2 Contact Information
(1) Department of Sport Science, Korea Institute of Sport Science, Seoul, Korea
(2) Graduate School of Physical Education, Kyung Hee University, Yongin, South Korea
(3) Department of Kinesiology, University of Indianapolis, Indianapolis, IN, USA
Accepted: 18 January 2010 Published online: 21 February 2010
Communicated by Susan Ward.
Abstract
Walk training with blood flow occlusion (OCC-walk) leads to muscle hypertrophy; however, cardiorespiratory endurance in response to OCC-walk is unknown. Ischemia enhances the adaptation to endurance training such as increased maximal oxygen uptake ($$ V{\text{O}}_{{ 2_{ \max } }} $$) and muscle glycogen content. Thus, we investigated the effects of an OCC-walk on cardiorespiratory endurance, anaerobic power, and muscle strength in elite athletes. College basketball players participated in walk training with (n = 7) and without (n = 5) blood flow occlusion. Five sets of a 3-min walk (4–6 km/h at 5% grade) and a 1-min rest between the walks were performed twice a day, 6 days a week for 2 weeks. Two-way ANOVA with repeated measures (groups × time) was utilized (P < 0.05). Interactions were found in $$ V{\text{O}}_{{ 2_{ \max } }} $$ (P = 0.011) and maximal minute ventilation (VEmax; P = 0.019). $$ V{\text{O}}_{{ 2_{ \max } }} $$ (11.6%) and VEmax (10.6%) were increased following the OCC-walk. For the cardiovascular adaptations of the OCC-walk, hemodynamic parameters such as stroke volume (SV) and heart rate (HR) at rest and during OCC-walk were compared between the first and the last OCC-walk sessions. Although no change in hemodynamics was found at rest, during the last OCC-walk session SV was increased in all five sets (21.4%) and HR was decreased in the third (12.3%) and fifth (15.0%) sets. With anaerobic power an interaction was found in anaerobic capacity (P = 0.038) but not in peak power. Anaerobic capacity (2.5%) was increased following the OCC-walk. No interaction was found in muscle strength. In conclusion, the 2-week OCC-walk significantly increases $$ V{\text{O}}_{{ 2_{ \max } }} $$ and VEmax in athletes. The OCC-walk training might be used in the rehabilitation for athletes who intend to maintain or improve endurance.
Delayed-onset muscle soreness induced by low-load blood flow-restricted exercise
Journal European Journal of Applied Physiology
Publisher Springer Berlin / Heidelberg
ISSN 1439-6319 (Print) 1439-6327 (Online)
Issue Volume 107, Number 6 / December, 2009
Category Original Article
DOI 10.1007/s00421-009-1175-6
Pages 687-695
Subject Collection Biomedical and Life Sciences
SpringerLink Date Thursday, September 03, 2009
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Original Article
Delayed-onset muscle soreness induced by low-load blood flow-restricted exercise
Jonathan D. Umbel1, 2, Richard L. Hoffman1, 2, Douglas J. Dearth1, 2, Gary S. Chleboun1, 3, Todd M. Manini4 and Brian C. Clark1, 2 Contact Information
(1) Institute for Neuromusculoskeletal Research, Ohio University, Athens, OH, USA
(2) Department of Biomedical Sciences, Ohio University COM, 211 Irvine Hall, Athens, OH 45701, USA
(3) School of Physical Therapy, Ohio University, Athens, OH, USA
(4) Department of Aging and Geriatric Research, Institute on Aging, University of Florida, Gainesville, FL, USA
Accepted: 13 August 2009 Published online: 29 August 2009
Abstract We performed two experiments to describe the magnitude of delayed-onset muscle soreness (DOMS) associated with blood flow restriction (BFR) exercise and to determine the contribution of the concentric (CON) versus eccentric (ECC) actions of BFR exercise on DOMS. In experiment 1, nine subjects performed three sets of unilateral knee extension BFR exercise at 35% of maximal voluntary contraction (MVC) to failure with a thigh cuff inflated 30% above brachial systolic pressure. Subjects repeated the protocol with the contralateral limb without flow restriction. Resting soreness (0–10 scale) and algometry (pain–pressure threshold; PPT) were assessed before and 24, 48 and 96 h post-exercise. Additionally, MVC and vastus lateralis cross-sectional area (CSA) were measured as indices of exercise-induced muscle damage. At 24-h post-exercise, BFR exercise resulted in more soreness than exercise without BFR (2.8 ± 0.3 vs 1.7 ± 0.5) and greater reductions in PPT (15.2 ± 1.7 vs. 20 ± 2.3 N) and MVC (14.1 ± 2.5% decrease vs. 1.5 ± 4.5% decrease) (p ? 0.05). In experiment 2, 15 different subjects performed three sets of unilateral BFR exercise at 35% MVC with one limb performing only the CON action and the contralateral performing the ECC action. The aforementioned indices of DOMS were assessed before exercise and 24, 48 and 96 h post-exercise. At 24 h post-exercise, CON BFR exercise resulted in more resting soreness than ECC BFR exercise (3.0 ± 0.5 vs. 1.6 ± 0.4), and a greater decrease in MVC (9.8 ± 2.7% decrease vs. 3.4 ± 2.5% decrease) (p ? 0.05). These data suggest that knee extension BFR exercise induces mild DOMS and that BFR exercise elicits muscle damage under atypical conditions with low-tension concentric contractions.
Prevention of Disuse Muscular Weakness by Restriction of Blood Flow
KUBOTA, ATSUSHI; SAKURABA, KEISHOKU; SAWAKI, KEISUKE; SUMIDE, TAKAHIRO; TAMURA, YOSHIFUMI
Abstract
Purpose: The aim of the present study was to compare the effects of periodic restriction of blood flow to lower extremities with those of isometric exercise on disuse muscular atrophy and weakness induced by immobilization and unloading.
Methods: The left ankle of each of 15 healthy males was immobilized for 2 wk using cast, and subjects were instructed to walk using crutches with non-weight bearing during this period. Subjects were divided into three groups: a restriction of blood flow (RBF) group (application of external compressive force of 200 mm Hg for 5 min followed by 3 min of rest, repeated five times in a single session, two sessions per day for 14 d); an isometric training (IMT) group (20 "exercises" of 5-s isometric contraction of the knee extensor, flexor, and ankle plantar flexor muscles followed by rest, twice a day, daily for 2 wk); and a control (CON) group (no intervention). We measured changes in muscle strength, thigh/leg circumferences, and serum growth hormone levels.
Results: Immobilization/unloading resulted in significant decreases in muscle strength of knee extensor and flexor muscles (P < 0.01 and < 0.05, respectively) and thigh and leg circumferences (P < 0.05, each) in the CON group, and significant decreases in muscle strength of the knee flexor muscles, ankle plantar flexor muscles, and leg circumference (P < 0.05) in the IMT group. RBF protected against these changes in muscle strength and thigh/leg circumference (P < 0.01 and < 0.05, respectively). No changes in serum growth hormone levels were noted.
Conclusion: Our results indicate that repetitive restriction of blood flow to the lower extremity prevents disuse muscular weakness.
Comparison of hormone responses following light resistance exercise with partial vascular occlusion and moderately difficult resistance exercise without occlusion
Greg V. Reeves,1 Robert R. Kraemer,1 Daniel B. Hollander,1 Jordan Clavier,1 Craig Thomas,1 Michelle Francois,2 and V. Daniel Castracane3
Departments of 1Kinesiology and Health Studies and 2Nursing, Southeastern Louisiana University, Hammond, Louisiana; and 3Texas Tech Health Sciences Center, Lubbock, Texas
Submitted 14 April 2006 ; accepted in final form 8 August 2006
Previous studies of contracting muscle with low loading and partial vascular occlusion demonstrated hypertrophy and strength adaptations similar to and exceeding those observed with traditional moderate to high resistance (Shinohara M, Kouzaki M, Yoshihisa T, and Fukunaga T. Eur J Physiol 77: 189–191, 1998; Takarada Y, Takazawa H, Sato Y, Takebayashi S, Tanaka Y, and Ishii N. J Appl Physiol 88: 2097–2106, 2000; Takarada Y, Sato Y, and Ishii N. Eur J Physiol 86: 308–314, 2002). The purpose of the study was to determine the anabolic and catabolic hormone responses to light resistance exercise combined with partial vascular occlusion. Three experimental conditions of light resistance with partial occlusion (LRO), moderate resistance with no occlusion (MR), and partial occlusion without exercise (OO) were performed by eight healthy subjects [mean 21 yr (SD 1.8)]. Three sets of single-arm biceps curls and single-leg calf presses were completed to failure with 1-min interset rest periods. Workloads of 30 and 70% one repetition maximum for each exercise were lifted for the LRO and MR trials, respectively. Blood samples were taken preexercise, postexercise, and 15 min postexercise for each experimental condition. Lactate increased significantly in the LRO and MR trials and was not significantly different from each other at any time point. Growth hormone (GH) increased significantly by fourfold from pre- to postexercise in the LRO session but did not change significantly during this time period in the MR and OO trials (8.3 ± 2.3 vs. 2.1 ± 1.2 and 2.6 ± 0.94 µg/l; respectively, P < 0.05). There were no changes in resting total testosterone [T; mean 15.7 ± 1.6 (SE) nmol/l], free testosterone (FT; 54.1 ± 4.5 pmol/l), or cortisol (267.6 ± 22 nmol/l) across all trials and times. In conclusion, with similar lactate responses, light exercise combined with partial vascular occlusion elicits a greater GH response than moderate exercise without occlusion but does not affect T, FT, or cortisol.