Adarq.org
Performance Area => Peer Reviewed Studies Discussion => Topic started by: adarqui on June 07, 2009, 02:45:04 am
-
Of course there could be a million studies in here.. There are some other VJ studies in the other topics, but regardless, any study related to vertical jump can be put in here.
1. The influence of squat depth on maximal vertical jump performance
Because jumping from a deep squat is rarely practised, it is unlikely that these jumps were optimally coordinated by the participants. Differences in experimental vertical ground reaction force patterns also suggest that jumps from a deep squat are not optimally coordinated. These results suggest there is the potential for athletes to increase jump performance by exploiting a greater range of motion.
2. Effects of ballistic training on preseason preparation of elite volleyball players.
The treatment group produced a significant increase in both SJR (STANDING JUMP) and AJR (APPROACH JUMP) of 5.9 +/- 3.1% and 6.3 +/- 5.1%, respectively. These increases were significantly greater than the pre- to postchanges produced by the control group, which were not significant for either jump. Analysis of the data from the various other jump tests suggested increased overall force output during jumping, and in particular increased rate of force development were the main contributors to the increased jump height.
Conclusions: These results lend support to the effectiveness of ballistic resistance training for improving vertical jump performance in elite jump athletes.
3. INFLUENCE OF TRAINING BACKGROUND ON JUMPING HEIGHT
The power-trained
group jumped significantly higher (p
0.05) than the BB and
PA groups (0.40
0.05, 0.31
0.04, and 0.30
0.05, respec-
tively). The difference in jumping height was not produced by
higher rates of force development (RFD) and shorter center of
mass (CM) displacement. Instead, the PT group had greater CM
excursion (p
0.05) than the other groups. The PT and BB
groups had a high correlation between jumping height and 1RM
test (r
0.93 and r
0.89, p
0.05, respectively). In conclusion,
maximum strength seems to be important for jumping height,
but RFD does not seem relevant to achieve maximum jumping
heights. High RFD jumps should be performed during training
only when sport skills have a time constraint for force applica-
tion
-
The influence of squat depth on maximal vertical jump performance
An increase in the period over which a muscle generates force can lead to the generation of greater force and, therefore, for example in jumping, to greater jump height. The aim of this study was to examine the effect of squat depth on maximum vertical jump performance. We hypothesized that jump height would increase with increasing depth of squat due to the greater time available for the generation of muscular force. Ten participants performed jumps from preferred and deep squat positions. A computer model simulated jumps from the different starting postures. The participants showed no difference in jump height in jumps from deep and preferred positions. Simulated jumps produced similar kinematics to the participants' jumps. The optimal squat depth for the simulated jumps was the lowest position the model was able to jump from. Because jumping from a deep squat is rarely practised, it is unlikely that these jumps were optimally coordinated by the participants. Differences in experimental vertical ground reaction force patterns also suggest that jumps from a deep squat are not optimally coordinated. These results suggest there is the potential for athletes to increase jump performance by exploiting a greater range of motion.
Effects of ballistic training on preseason preparation of elite volleyball players.
Applied Sciences
Medicine & Science in Sports & Exercise. 31(2):323-330, February 1999.
NEWTON, ROBERT U.; KRAEMER, WILLIAM J.; HAKKINEN, KEIJO
Abstract:
Effects of ballistic training on preseason preparation of elite volleyball players. Med. Sci. Sports Exerc., Vol. 31, No. 2, pp. 323-330, 1999.
Purpose: The purpose of this study was to determine whether ballistic resistance training would increase the vertical jump (VJ) performance of already highly trained jump athletes.
Methods: Sixteen male volleyball players from a NCAA Division I team participated in the study. A Vertec was used to measure standing vertical jump and reach (SJR) and jump and reach from a three-step approach (AJR). Several types of vertical jump tests were also performed on a Plyometric Power System and a forceplate to measure force, velocity, and power production during vertical jumping. The subjects completed the tests and were then randomly divided into two groups, control and treatment. All subjects completed the usual preseason volleyball on-court training combined with a resistance training program. In addition, the treatment group completed 8 wk of squat jump training while the control group completed squat and leg press exercises at a 6RM load. Both groups were retested at the completion of the training period.
Results: The treatment group produced a significant increase in both SJR and AJR of 5.9 +/- 3.1% and 6.3 +/- 5.1%, respectively. These increases were significantly greater than the pre- to postchanges produced by the control group, which were not significant for either jump. Analysis of the data from the various other jump tests suggested increased overall force output during jumping, and in particular increased rate of force development were the main contributors to the increased jump height.
Conclusions: These results lend support to the effectiveness of ballistic resistance training for improving vertical jump performance in elite jump athletes.
INFLUENCE OF TRAINING BACKGROUND ON JUMPING HEIGHT
A
BSTRACT
. Ugrinowitsch, C., V. Tricoli, A.L.F. Rodacki, M. Ba-
tista, and M.D. Ricard. Influence of training background on
jumping height. J. Strength Cond. Res. 21(3):848–852. 2007.—
The aim of this study was to compare the pattern of force pro-
duction and center of mass kinematics in maximal vertical jump
performance between power athletes, recreational bodybuilders,
and physically active subjects. Twenty-seven healthy male sub-
jects (age: 24.5
4.3 years, height: 178.7
15.2 cm, and weight:
81.9
12.7 kg) with distinct training backgrounds were divided
into 3 groups: power track athletes (PT, n
10) with interna-
tional experience, recreational bodybuilders (BB, n
7) with at
least 2 years of training experience, and physically active sub-
jects (PA, n
10). Subjects performed a 1 repetition maximum
(1RM) leg press test and 5 countermovement jumps with no in-
structions regarding jumping technique. The power-trained
group jumped significantly higher (p
0.05) than the BB and
PA groups (0.40
0.05, 0.31
0.04, and 0.30
0.05, respec-
tively). The difference in jumping height was not produced by
higher rates of force development (RFD) and shorter center of
mass (CM) displacement. Instead, the PT group had greater CM
excursion (p
0.05) than the other groups. The PT and BB
groups had a high correlation between jumping height and 1RM
test (r
0.93 and r
0.89, p
0.05, respectively). In conclusion,
maximum strength seems to be important for jumping height,
but RFD does not seem relevant to achieve maximum jumping
heights. High RFD jumps should be performed during training
only when sport skills have a time constraint for force applica-
tion
-
wow squid would probably get a massive erection if he discovered that the rfd wasnt important in jumping.
-
http://athletesunited.net/Articles/TrainingforVert.htm (http://athletesunited.net/Articles/TrainingforVert.htm) i really liked this article!
-
http://athletesunited.net/Articles/TrainingforVert.htm (http://athletesunited.net/Articles/TrainingforVert.htm) i really liked this article!
very nice article, quick overview & nice comparison charts.. very useful.
peace!
-
i really found it interesting that at some point just max strength squatting will make you slower if you don't incorporate any explosive work or jumps
-
i really found it interesting that at some point just max strength squatting will make you slower if you don't incorporate any explosive work or jumps
yup, regardless of explosive work, excessive strength work can still cause decreases in RFD, especially when the weights get very big. If one is allowed to move heavy weight slowly, then those gains in strength won't translate well to improving explosive strength, at all, in fact it will hurt it.. for example, say you squat 2xBW in 2s, well, if you become squat-obsessed and end up squatting 2.5xBW in 5-6 seconds, those gains in maximal strength past 2x probably won't transfer well to explosive movements.. an emphasis on bar speed has to be there, otherwise you're just training slow like a power lifter.. oly lifters with huge squats, usually do them very fast.. check the 69kg lifter thread in the oly lifting subforum, boevsky 3.6xBW squat, very fast.. then check his oly lifting performance.. just clean's the bar like it's nothing.. so ya that power translates, but obviously, if he had a 3.6xBW PL squat that takes 5+ seconds, that power definitely wouldn't be there in his oly's/explosive movements.
pc
-
It is sort of funny to read what scholars have to say about the topic of VJ training. I am extremely skeptical towards this information because it is usually based on poorly designed research with limited application value. The information in the article is really shallow, especially regarding appropriate training design. It is just stating conventional wisdom and many points can be debated. I heavily disagree with the standard advice to use a periodization model for everything regardless of training level and I think this is just a waste of time and display of a poor understanding of what will be necessary for example for an athlete without previous exposure to strength training.
The hesitancy on the topic of heavy vs. light loads for strength training I find especially amusing. Those guys are seriously suggesting that it MIGHT be good to let an athlete do "strength" training with <70% of his 1rm? This MIGHT be better because it does not take as long to lift the load? There are so many things wrong and illogical about this thought, that not even the opposite is true and one has to doubt if those people have actually put any thought into this instead of blindly adopting things others have said before to give apology for their idiotic research.
Regarding squat strength: Lifting a heavy weight will slow the lift down. A 1rm will look rather slow for the squat, otherwise it is not a 1rm. The last 1 or 2 reps of a 5rm might look rather similar. Here is the thing though: After you got those last 2 rather slow reps, you might next time be able to do the same number of reps with 5 lbs more and in a month you might have a 5rm considerably heavier than previously. The last reps of that new 5rm will still look slow, but how does the set look like with your previous 5rm weight? Probably not so slow anymore - I think everyone can follow that thought. Now, will that squat strength transfer to gains in the VJ? No, not if the guy training is in fact more advanced than a novice strength trainee. But we are doing resisted explosive lifts, right? See, they do take care of that problem ridiculously well if used correctly. What happened during the heavy training though is that we gained strength and muscle which makes progress in the explosive lifts a lot easier which in turn helps with jumping tremendously.
Now, when we would instead have trained with super light weights, what would have happened is that maybe we would have gotten a little stronger and that strength might even be relatively transferable to a VJ. But the gains would have been vastly inferior considering the trainee did stall in a power phase earlier on. The reason being that max strength, a necessary component of power, would still be a limiting factor.
-
for example, say you squat 2xBW in 2s, well, if you become squat-obsessed and end up squatting 2.5xBW in 5-6 seconds, those gains in maximal strength past 2x probably won't transfer well to explosive movements
Agreed. However, consider this possibility:
Athlete A:
Squats 2.0xbw in 2s
Three months later
Squats 2.5xbw in 4s
Squats 2.0xbw in 1.75s
I think going from a 2xbw squat to a 2.5xbw squat is more effective in increasing the amount of time it takes to squat 2xbw (in terms of how long the rep takes) versus incorporating RFD work and not increasing to a 2.5xbw squat.
Not only that, but the RFD work may fade away over time once you switch to more strength oriented work, and you wouldn't be able to keep up with that 2xbw squatting speed.
I prefer strength work over RFD work pretty much all the time. Plyos, on the other hand, are a bit of a different story imo (yes I know they increase RFD as well).
-
I agree with Lakers...
The lower a % your whatever squat is (2x in this case) of your 1RM, the faster you'll usually move it.
-
for example, say you squat 2xBW in 2s, well, if you become squat-obsessed and end up squatting 2.5xBW in 5-6 seconds, those gains in maximal strength past 2x probably won't transfer well to explosive movements
Agreed. However, consider this possibility:
Athlete A:
Squats 2.0xbw in 2s
Three months later
Squats 2.5xbw in 4s
Squats 2.0xbw in 1.75s
I think going from a 2xbw squat to a 2.5xbw squat is more effective in increasing the amount of time it takes to squat 2xbw (in terms of how long the rep takes) versus incorporating RFD work and not increasing to a 2.5xbw squat.
well sure but i'm talking incorporating RFD work WHILE you increase to 2.5xBW squat.. i'm saying that has to be utilized, to make sure squat gains always have a speed emphasis.. explosive RFD work while utilizing max strength methods, results in faster reps than if you had just been squatting alone, at least that's been my experience and what i've seen in the field..
Not only that, but the RFD work may fade away over time once you switch to more strength oriented work, and you wouldn't be able to keep up with that 2xbw squatting speed.
to me, it's not about it 'fading', it's about using it as a constant tool to stimulate/potentiate better squat/jump sessions.
sure it fades fast, but that's because the body 'wants to get slower' to lift more weight.. it's a highly type IIa low velocity stimulus.
I prefer strength work over RFD work pretty much all the time. Plyos, on the other hand, are a bit of a different story imo (yes I know they increase RFD as well).
yes most of us need strength work more than pure rfd work, that's if we had to choose.. but i'm for both concurrently.
ya plyos are still RFD work.. for resistance RFD work, I like REA squat, jump squat, and/or REA low squat ankle hops.
really love those REA LSAH's.
pc
-
Oh and I'm still confused about some stuff on RFD "vs" plyos. Like is there a need to do resisted RFD when you can just do plyos? I'm asking because plyos also increase explosive strength as well as elastic strength, and I feel like you'll get more bang for your buck doing an extra set of depth jumps versus a few sets of paused weighted jumps squats.
-
Oh and I'm still confused about some stuff on RFD "vs" plyos. Like is there a need to do resisted RFD when you can just do plyos? I'm asking because plyos also increase explosive strength as well as elastic strength, and I feel like you'll get more bang for your buck doing an extra set of depth jumps versus a few sets of paused weighted jumps squats.
well I prefer reactive/plyos over traditional rfd work (jump squat, oly's), for sure, but traditional rfd work is more necessary for people who are interested in SVJ.
regardless, depth jumps can still improve SVJ.. other reactive work, for example, bounds & other rebounding drills, are less effective at increasing RFD without considerable preloading..
so, if you're more into RVJ (short run ups or full), then ya, you could definitely just focus completely on reactive work.. your more intense exercises would be:
- depth jumps & single leg bounds
Accessory reactive work would be:
- MR drills (half tucks, pogos, double leg bounds)
- jump rope/sprints
so, when it comes to generating forces without considerable preload, oly's/jump squats/rea squat etc will yield more gains.
pc
-
Well I mean there's still significant reactive "activity" for lack of a better term in the SVJ, and since depth jumps increase "voluntary RFD" as well as "involuntary RFD" I feel like there's really no need for traditional RFD work unless added in for variety.
-
add these to index when you get "unlazy":
http://www.springerlink.com/content/w0281m2811x34132/
A work-energy approach to determine individual joint contributions to vertical jump performance
C. L. Hubley and R. P. Wells
Abstract
A work-energy approach was used to determine the contributions of the muscles crossing the hip, knee and ankle joints to the total positive work done during maximal vertical jumps. It was found that the average relative contributions of the ankle and hip muscles were approximately 23 and 28% respectively, with the remaining 49% of the work being done by the muscles acting at the knee joint. The efficiency of jumping, i.e. the ratio of potential energy gained to the net mechanical work done by the muscles acting at the three lower limb joints was nearly 1.0. These results stress the importance of all three major leg extensor muscle groups to the performance of an explosive activity such as vertical jumping. It is suggested that the work-energy approach supplies useful information concerning joint contributions without the problems associated with other techniques.
Title: Performance of a two-foot vertical jump: What is more important hip or knee dominance?
Authors: Patel, Rupesh
Keywords: vertical jump
strategy
performance
hip
knee
core
Approved Date: 22-Dec-2010
Date Submitted: 22-Dec-2010
Abstract: Vertical jumping ability is an important fundamental skill for many athletic activities. The present work is focused on developing an understanding of the role of various movement strategies on vertical jump performance. The overall objective of this study was to determine if higher hip than knee joint contribution was more effective in enhancing vertical jump height. Additionally, the study explored possible links between the muscle activity and mechanical outputs, and to develop understanding of the role of the lumbar spine and hip. Twenty male university varsity athletes performed ten repetitions of three jumping strategies: preferred, hip dominant and knee dominant. Kinematics, kinetics and muscle activity of the lower limb and trunk were collected. The main observation was that the vertical jump height was positively associated with higher hip than knee work done. However, the within-subject comparisons between the trained hip and knee dominant tasks did not provide additional support for the importance of the hip. Higher hip work appeared associated with greater biceps femoris than gluteus maximus activity. The knee work increased with higher activity of the vastus lateralis and rectus femoris. Finally, higher trunk muscle activity and tighter coupling were associated with the vertical jump height and the max force. This study provides some evidence that encouraging hip dominance together with higher spine stiffness may improve two-foot vertical jump performance. This work has potential implications for training protocols that may be used to improve vertical jump performance.
Time-of-day effect on patella tendon stiffness alters vastus lateralis fascicle length but not the quadriceps force–angle relationship
* N.L. Gladys Onambele-Pearson
Affiliations
o Institute of Biophysical and Clinical Research into Human Movement, Department of Exercise and Sport Science, Manchester Metropolitan University, Hassall Road, Alsager, England ST7 2HL, UK
o Corresponding Author InformationCorresponding author. Tel.: +441612475594; fax: +441612476375.
email address
* , Stephen J. Pearson
Affiliations
o Centre for Rehabilitation and Human Performance Research, Directorate of Sport, University of Salford Manchester, England M6 6PU, UK
Accepted 4 April 2006. published online 10 July 2006.
* Abstract
* Full Text
* PDF
* Images
* References
Abstract
Aim
To examine the time-of-day (TOD) effect on torque–force/angle, fibre length (FL), tendon stiffness (K), stress, and strain using the quadriceps muscle–tendon complex as a model.
Methods
Twelve healthy young men (aged 27±2.0 years) were studied at AM (7h45) and PM (5h45). Maximal isometric contractions were carried out on an isokinetic dynamometer, with real-time recordings of vastus lateralis (VL) FL and patella tendon K using B-mode ultrasonography. Percutaneous electrical twitch doublets superimposed on maximal torque were used to test for muscle activation capacity (AC).
Results
At PM, torque and force increased by 16±3.0% () over 30–90° knee angles. Where the load was standardised (at 250N) in order to discriminate between torque generation capacity and tendon K changes, PM relative to AM, there were 8% and 13% () reductions in relaxed and contracted FL, respectively. Average K decreased by 21% () and the maximal stress and strain were increased at PM by 11% and 16%, respectively (). No TOD effect on AC was seen.
Conclusion
The quadriceps torque or force–angle relationships shift upwards at PM vs. AM, with no shift in the position of the optimal knee angle. This torque or force increase appears not to be centrally modulated. Although K decreases with TOD thereby potentially shortening the working length of the sarcomeres, these changes overall do not affect the ability of the muscle to produce greater torque in the evening.
-
Hey, speaking of the deep squat position for vertical jumping study... anyone ever notice how deep dee brown gets in his jumping?
Here is a clip from the 1991 dunk contest
http://www.youtube.com/watch?v=FgfIrCTjud0
Good studies though, I'll have to read them and try and get a few comments/discussion going.
-
You want deep, check out 1:00 here:
http://www.youtube.com/watch?v=79oVy1pw1Xw
-
holy sh%t.... actually though, this is how a lot of awesome two leg jumpers take off, his center of mass is crazy low, but his left leg doesn't bend all that much. Just working speed and com lowering to his best advantage. That right leg is bent pretty far though, but I think most of the force is going to the left leg. This is kind what gives a lot of "speed" high jumpers their lift without them bending their knee much, because they are leaning to the side which lowers the center of mass.
-
I think the reality is that in T-Dub's case, that first leg that he plants LOADS a lot muscularly, also spends more time than the left leg on the ground and therefore contributes more muscularly and it kind of loads more due to the twisting occuring onto it as well which, in my opinion, helps "stress" the CNS and recruit more muscle.
-
this is what I want to see.... a study showing the link between fiber type and knee bend in standing vertical jump with no instruction given and then instruction given and see what results happen. It seems like those who are more slow twitch oriented would do better by digging down further to jump, as they would have more time to produce force. if I get my Ph.d maybe I could do my dissertation on this ;)
I have a sprinter on the track team though, who seems to be pretty fast twitch oriented and likes to do his standing vertical tests by going way past 90 degrees. He isn't very athletic though... didn't play any jumping sports in hs. His standing VJ is about 30-32" on the jump mat. He can parallel squat 275 at 145lbs. He also runs the 200 in about 23.0, although he would have broke 23 if I was coaching the long sprints this past year ;) all my other sprinters/jumpers don't use past 90 knee bend.
What is crazy is that Dee Brown does his running dunks with such great knee bend, that is a lot of force out of the hole there.
-
It's not that easy. There are structural factors, sleeping vs active muscles, flexibility issues, previous/current injuries and so on and so forth that factor in quite a bit in determining what is going to happen in terms of bending or knee vs hip bend.
-
There are a ton of factors that all come into play here, and they can also be changed through different types of training, some for better, some for worse.
One thing that I have noticed simply through years of observation is athletes with a very long tibia relative to the femur will not have the same "weak" spot that athletes with longer femur to tibial ratios, and can descend further without a loss of power in the svj. These same athletes seem to be able to get more of the hips into any jump they do as the length of the shorter femur pivoting around a longer tibia is advantageous for that extra depth without moving the center of mass too far away from the fulcrum.
This is only one of many factors, but this type of athlete will actually benefit from a little deeper gather during the jump, dee brown looks to be a pretty good example of this. It would definitely be interesting to see some good studies done on it.
-
I think you might have something going on with that ^^^
-
I can see how the tibia/femur ratio can make sense. Thinking about it a bit more.... I think squat strength is a big inflencing factor, as when you look at most any football player, they get down pretty deep as well. That cam wake 11'8 jump is a good example too. Then again, I remember watching staffan strand do some standing high jumps, and he dug down unbelievably far, especially for a high jumper with a bad squat.
I have long tibia length compared to my femur, but I can't squat for sh#t (not being able to hit 2.0x when you have been lifting for 13 years is kind of weak), and I have less knee bend than anyone I know on my standing vertical. A lot of this though is because I get a lot of power out of my upper body, and my legs play a slightly more reactive function than most. I suppose there are a lot of factors, I would like to see more research on it.
I bet achilles length and structure has something to do with it as well, a great study in the JSCR came out a few months ago talking about how athletes with differently structured muscle-tendon complexes in their calves produced force differently in standing and running verticals. Long tendons were good for standing vertical jumps, and short were not good. Case in point I had a swedish long jumper who went 22' this past year and wasn't that fast either, who only had a 25" standing vertical. His achilles were really short.... and so are Stefan Holm's for that matter, and his standing vertical is like... half of his running. KB wrote about that in one of his recent articles too.
I would be really interested if more research came out on the knee bend topic as well.
-
A lot of this though is because I get a lot of power out of my upper body, and my legs play a slightly more reactive function than most.
Interesting. I think that might be true, if you were lacking the upperbody strength that you have right now you'd probably bend more in the body's effort to find more strength resources.
-
00:21 in the TDUB video is insane. Looks like he has a lot of strength, that's the first time I've seen him jump without his usually 3 step approach.
http://faculty.fullerton.edu/leebrown/PDF%20Files/Academic/McBride-heavy%20vs%20light%20load%20training.pdf
THis study found that jump squats using 30% 1RM were way more effective than at 80% 1RM. They did not test vertical jump, but they tested performance on jump squats using 30, 55, an 80% 1RM using a force plate. THey also tested 20 meter sprint. Problems is that they used a smith machine, and were told to lower the weight in a controlled manner (wold like to see the video), but subjects were instructed to accelerate the bar as fast as possible.
Results:
-1RM increased as expected more in the 80% jump squat group more than the 30%, and relative strength increased as well.
-The 30% JS group increased jump height more than the 80% at all weights tested, that means the 30% jump squat was more effective at increasing jump height in the 80% jump squat even compared to the group that actually trained with 80% jump squats- pretty crazy results.
-Peak force improved more in the 80% JS group in testing post-study, however peak power and peak velocity improve much more in the 30% JS group.
"The JS30 group had
an overall trend of improved velocity capabilities regardless of the load in the jump-squat tests."
Very nice tables to check out in there.
Edit: especially table 3 page 80. Notice the 30js group is producing more power in the 80% 1rm jump squat test than the group that trained with 80%.
-
I just read this study and am interested in other peoples' opinion on it as I have just recently added js into my routine. I have very little experience deciphering research studies but there a few things that seem strange to me on this one, some of which Avishek has already mentioned:
-Smith machine
-No bw vj pre/post testing
-1RM squat % calc @knee angle of 80', not parallel or ATG
-EMG for vastus lateralis only
-Control group increased 1RM by over 6% - how? (Table 2)
-Much more work(43%) done by JS80% group than JS30% - overtrained? (Table 2)
-BF%/BW went down for JS30, abt same for JS80, up for Control grp (Table 1)
-No wt or diet control for subjects
-Jump height on 55% JS test up ~8% on control grp, abt same as JS30 grp, WTF? (Figure 3)
-Jump ht up the most (>12%) on the control grp for the 80% JS test when they did no 80% jumping at all?? WTFx2 (Fig 4)
Any thoughts on this study and its validity/conclusions would be appreciated.
-
Wow I didn't even notice the control group's gains in the 80JS. Maybe they entered their values wrong? THe control group is producing less power than the others at the 80%JS test but jump higher? Wtf..
Anyway here are some of my thoughts. Something to always keep in mind in these sport related studies is the athletic abilities of the participants. We have no data on their training experience or program other than that they play intamural sports. They seem to have high starting strength levels though, if you look at their 1RM, averages are above 300lbs.
So perhaps these participants had been perforing slower weight training already and so more slow weight training as in the 80%1rm jump squats, did not help them in jum performance.
For athletes with lower starting 1RMs, we might have seen a better result from the heavier jump squats. It would also be interesting to see if we took athletes with 40 inch running verticals and tried this protocol on them to compare light fast training to slower and heavier training. The fact that their sprint times decreased is nothing new though. SPrinting is something totally different
Edit: i think most atheltes here would agree with my analysis. But I tend to disagree with this conventional wisdom. I think lighter training may be a better idea. A lot of us really believe in maximal strength training, when the forces in vertical jump aren't near what is seen in maximal strength training. Maximal strength increases will only help one jump higher by increasing their power output in the short time of a ground contact, so a better term is maximal exploive strength expressed in 200 milliseconds or less. Once ai get to a 50 inch vertical I'll talk more though.
-
Wow I didn't even notice the control group's gains in the 80JS. Maybe they entered their values wrong? THe control group is producing less power than the others at the 80%JS test but jump higher? Wtf..
Anyway here are some of my thoughts. Something to always keep in mind in these sport related studies is the athletic abilities of the participants. We have no data on their training experience or program other than that they play intamural sports. They seem to have high starting strength levels though, if you look at their 1RM, averages are above 300lbs.
So perhaps these participants had been perforing slower weight training already and so more slow weight training as in the 80%1rm jump squats, did not help them in jum performance.
For athletes with lower starting 1RMs, we might have seen a better result from the heavier jump squats. It would also be interesting to see if we took athletes with 40 inch running verticals and tried this protocol on them to compare light fast training to slower and heavier training. The fact that their sprint times decreased is nothing new though. SPrinting is something totally different
Edit: i think most atheltes here would agree with my analysis. But I tend to disagree with this conventional wisdom. I think lighter training may be a better idea. A lot of us really believe in maximal strength training, when the forces in vertical jump aren't near what is seen in maximal strength training. Maximal strength increases will only help one jump higher by increasing their power output in the short time of a ground contact, so a better term is maximal exploive strength expressed in 200 milliseconds or less. Once ai get to a 50 inch vertical I'll talk more though.
From the way I read the study, they measured their 1RM at an 80' knee angle though, which is basically a half-squat, and is why their 1RM #s & their 1RM/Wt ratios are so high. This is the 1st thing that caught my attention bcs these strength ratios are far from typical for intramural sport athletes. So they are basing their 30/55/80% #'s on the % of a HALF-SQUAT, not FULL-SQUAT, which I thought was very strange and different from the other similar studies and recommendations that I have seen.
-
True, but I don't think I can half squat that much..well maybe I can I should try. Yeah they should have really tested vertical jump that would have been cool.
I guess the best extrapolation we can make is that it would probably go up since power increased the most in the 30JS group
-
Body Composition and Muscle Strength Predictors of Jumping Performance: Differences Between Elite Female Volleyball Competitors and Nontrained Individuals
http://journals.lww.com/nsca-jscr/Abstract/2014/10000/Body_Composition_and_Muscle_Strength_Predictors_of.2.aspx
Abstract: Ćopić, N, Dopsaj, M, Ivanović, J, Nešić, G, and Jarić, S. Body composition and muscle strength predictors of jumping performance: Differences between elite female volleyball competitors and nontrained individuals. J Strength Cond Res 28(10): 2709–2716, 2014—Studies of the role of various anthropometric, physiological, and biomechanical variables in performance of rapid movements have generally revealed inconsistent findings. Within this study, we tested the hypotheses that (a) both body composition and leg extensor strength variables would reveal significant relationship with jumping performance, whereas (b) the same relationships would be stronger in physically active nonathletes than in the elite athletes proficient in vertical jumping. Top-level female volleyball players (VP; N = 35) and physically active female nonathletes (PA; N = 21) were tested on maximum vertical jumps performed with and without arm swing, as well as on body composition (percent fat and muscle) and leg press strength (maximum force and the rate of force development). The results revealed significant relationships between the jumping performance and body composition variables that appeared to be higher in PA (r = 0.65–0.76; all p < 0.01) than in VP (r = 0.37–0.42; all p ≤ 0.05). The relationships between the jumping performance and the leg strength variables were mainly significant (r = 0.23–0.68) and similar in 2 groups. We conclude that not only the leg extensor strength but also the body composition variables could be valid predictors of jumping performance and, possibly, other rapid movements. Moreover, the body composition variables that have been mainly neglected in the literature could be particularly strong predictors of performance of jumping in nonathletes, as compared with relatively homogeneous populations of elite athletes.