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« on: December 22, 2009, 12:05:48 pm » |
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Being an engineer i know well that the hangtime-vert calculation formula is 100% accurate, i even have my own excel version with the local gravity acceleration in the formula. I was thinking: The correct way to measure hangtime is to measure the time that the feet are in the air , from the first 'airborn' frame to the first 'touchdown frame'. But doesnt that mean that we have a different measurement here compared to the normal one ( highest touch minus flat-footed reach )? Instead of flat footed standing reach we are using 'toes-up' reach! That would make the vertical measurements different by an amount equal to the flat-footed vs toes-up reach difference, wich would be ~4-5''. What is your opinion? |
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adarqui
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« Reply #1 on: December 22, 2009, 02:57:05 pm » |
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Being an engineer i know well that the hangtime-vert calculation formula is 100% accurate, i even have my own excel version with the local gravity acceleration in the formula.
I was thinking:
The correct way to measure hangtime is to measure the time that the feet are in the air , from the first 'airborn' frame to the first 'touchdown frame'.
But doesnt that mean that we have a different measurement here compared to the normal one ( highest touch minus flat-footed reach )?
Instead of flat footed standing reach we are using 'toes-up' reach!
That would make the vertical measurements different by an amount equal to the flat-footed vs toes-up reach difference, wich would be ~4-5''.
What is your opinion?
well ya because, standing vert is a measure of how much your COM has changed from a flat-foot stand still.. so being up on the toes is changing the COM.. thats why in hangtime vids i always take the frame right before takeoff, still on the toes, but, right before your toes leave the ground.. this takes into account the 0.033s error also.. that gives you more of a vert number that is more similar to a vertec touch-reach. the 0.033s error on takeoff and landing is the biggest concern with hangtime formula, when using 30fps cameras.. best case you're dead on, worst case you're 0.066s off. ya it sux though i wish vertec's were ~20$.. vert training with one is so much better. |
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"Now Cornell University neurobiologists, studying the adrenal glands of rats, have discovered how chronic stress cranks up the intensity of this adrenaline response. The key to this so-called molecular memory resides in a donut-shaped protein on the surface of cells that secrete adrenaline, the hormone also known as epinephrine." PED's in drug free sports is cheating, unethical, and weak. Athletes and/or coaches who condone/display this behavior can get lost."But you have never felt the burn that you get in the hip flexors from pulling back on the pedal stroke, you have never done the exercise in your life. Squatting ain't doing shit for your hip flexors blu." -- sickenin vendetta. QuickMix: Gulf Dunk Mix: http://www.youtube.com/watch?v=9PHyFdbJnrY&hd=1The Promise Dunk Mix: http://www.youtube.com/watch?v=Ed5VRE0lOXU&hd=1Ballet Dunk Mix: http://www.youtube.com/watch?v=pI_c2dz0C_4&hd=1BoingTerd Dunk Session: http://www.youtube.com/watch?v=F6mHaUoNpOg&hd=1Dunk Films: dunk=surfing: http://www.youtube.com/watch?v=oAp_z9fVyMQMay 2011 Dunk Mix: http://www.youtube.com/watch?v=z7MYrl716-kMay13-2011 Nice dunk session: http://www.youtube.com/watch?v=73BhhFenp7o&feature=player_embeddedAPRIL 2011 DUNK RECAP/MIX: http://www.youtube.com/watch?v=VuPS1Sm10dsSome hard freakin` dunks: http://www.youtube.com/watch?v=3nukAo_IizA , http://www.youtube.com/watch?v=QU7URZQ3Y4U , http://www.youtube.com/watch?v=FMQo64DzV70WHO RUN IT DUNK MIX - PART 1: http://www.youtube.com/watch?v=xypWSL5YVEwadarq.org commercial #2: http://www.youtube.com/watch?v=QBYlngDcxFY = if at first you don't succeed, AMP THE F UP & TRY AGAIN. lion swag dunk mix: http://www.youtube.com/watch?v=hhyqcL4fO-gmisc dunk footage from 2/20/2011, gettin` up: http://www.youtube.com/watch?v=XhF8F43z5Ogend of 2010 dunk session: http://www.youtube.com/watch?v=P2fwJ8e5Vs8The "I think i'm dying dunk mix" : http://www.youtube.com/watch?v=XiXkdX5QLNo |
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vag
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« Reply #2 on: December 23, 2009, 02:48:09 am » |
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Well i just got a new mobile that features 120fps video, that minimizes the error to 1/120 of a second each side , so max error is 1/60 wich is 0,016666. I would still prefer the highest touch - standing reach measurement , but now highest touch is an aproximation , trying to see from the vid how much i got above a measured rim!  Im leaning towards the 120fps hangtime thing , jsut wanted your opinion. Probably gonna use both in next jump session to compare the results, that should be interesting... |
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adarqui
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« Reply #3 on: December 23, 2009, 03:28:49 am » |
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Well i just got a new mobile that features 120fps video, that minimizes the error to 1/120 of a second each side , so max error is 1/60 wich is 0,016666. I would still prefer the highest touch - standing reach measurement , but now highest touch is an aproximation , trying to see from the vid how much i got above a measured rim! Im leaning towards the 120fps hangtime thing , jsut wanted your opinion. Probably gonna use both in next jump session to compare the results, that should be interesting... whoa.. awesome!!!!!!!! 120fps = fun fun fun. cool man tell me how it goes.. with video timing, you can always take a few measurements... it would be interesting if you: - calculated rvj using touch - reach .. touch on rim of course.. - compared that to: video timing of heels barely off ground AND toes FULLY extended right at takeoff... both timed until first contact with ground. vag - psyence detective ( http://www.youtube.com/watch?v=FKl43SPgqCo) |
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"Now Cornell University neurobiologists, studying the adrenal glands of rats, have discovered how chronic stress cranks up the intensity of this adrenaline response. The key to this so-called molecular memory resides in a donut-shaped protein on the surface of cells that secrete adrenaline, the hormone also known as epinephrine." PED's in drug free sports is cheating, unethical, and weak. Athletes and/or coaches who condone/display this behavior can get lost."But you have never felt the burn that you get in the hip flexors from pulling back on the pedal stroke, you have never done the exercise in your life. Squatting ain't doing shit for your hip flexors blu." -- sickenin vendetta. QuickMix: Gulf Dunk Mix: http://www.youtube.com/watch?v=9PHyFdbJnrY&hd=1The Promise Dunk Mix: http://www.youtube.com/watch?v=Ed5VRE0lOXU&hd=1Ballet Dunk Mix: http://www.youtube.com/watch?v=pI_c2dz0C_4&hd=1BoingTerd Dunk Session: http://www.youtube.com/watch?v=F6mHaUoNpOg&hd=1Dunk Films: dunk=surfing: http://www.youtube.com/watch?v=oAp_z9fVyMQMay 2011 Dunk Mix: http://www.youtube.com/watch?v=z7MYrl716-kMay13-2011 Nice dunk session: http://www.youtube.com/watch?v=73BhhFenp7o&feature=player_embeddedAPRIL 2011 DUNK RECAP/MIX: http://www.youtube.com/watch?v=VuPS1Sm10dsSome hard freakin` dunks: http://www.youtube.com/watch?v=3nukAo_IizA , http://www.youtube.com/watch?v=QU7URZQ3Y4U , http://www.youtube.com/watch?v=FMQo64DzV70WHO RUN IT DUNK MIX - PART 1: http://www.youtube.com/watch?v=xypWSL5YVEwadarq.org commercial #2: http://www.youtube.com/watch?v=QBYlngDcxFY = if at first you don't succeed, AMP THE F UP & TRY AGAIN. lion swag dunk mix: http://www.youtube.com/watch?v=hhyqcL4fO-gmisc dunk footage from 2/20/2011, gettin` up: http://www.youtube.com/watch?v=XhF8F43z5Ogend of 2010 dunk session: http://www.youtube.com/watch?v=P2fwJ8e5Vs8The "I think i'm dying dunk mix" : http://www.youtube.com/watch?v=XiXkdX5QLNo |
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vag
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« Reply #4 on: December 24, 2009, 02:46:18 am » |
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whoa.. awesome!!!!!!!! 120fps = fun fun fun. cool man tell me how it goes.. with video timing, you can always take a few measurements... it would be interesting if you: - calculated rvj using touch - reach .. touch on rim of course.. - compared that to: video timing of heels barely off ground AND toes FULLY extended right at takeoff... both timed until first contact with ground. vag - psyence detective ( http://www.youtube.com/watch?v=FKl43SPgqCo) My thoughts exactly , word by word! Gonna have an ultra-epic "hangtime calculation vs reality" video up soon!  lolzzzzzz @ psyience detective |
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adarqui
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« Reply #5 on: December 24, 2009, 03:39:58 am » |
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whoa.. awesome!!!!!!!! 120fps = fun fun fun. cool man tell me how it goes.. with video timing, you can always take a few measurements... it would be interesting if you: - calculated rvj using touch - reach .. touch on rim of course.. - compared that to: video timing of heels barely off ground AND toes FULLY extended right at takeoff... both timed until first contact with ground. vag - psyence detective ( http://www.youtube.com/watch?v=FKl43SPgqCo) My thoughts exactly , word by word! Gonna have an ultra-epic "hangtime calculation vs reality" video up soon! lolzzzzzz @ psyience detective nice! cant wait to check it out should be cool lol @ psyence detective, he got 90 days in jail... i thought he'd get alot more to be honest.. at least more than a year. |
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"Now Cornell University neurobiologists, studying the adrenal glands of rats, have discovered how chronic stress cranks up the intensity of this adrenaline response. The key to this so-called molecular memory resides in a donut-shaped protein on the surface of cells that secrete adrenaline, the hormone also known as epinephrine." PED's in drug free sports is cheating, unethical, and weak. Athletes and/or coaches who condone/display this behavior can get lost."But you have never felt the burn that you get in the hip flexors from pulling back on the pedal stroke, you have never done the exercise in your life. Squatting ain't doing shit for your hip flexors blu." -- sickenin vendetta. QuickMix: Gulf Dunk Mix: http://www.youtube.com/watch?v=9PHyFdbJnrY&hd=1The Promise Dunk Mix: http://www.youtube.com/watch?v=Ed5VRE0lOXU&hd=1Ballet Dunk Mix: http://www.youtube.com/watch?v=pI_c2dz0C_4&hd=1BoingTerd Dunk Session: http://www.youtube.com/watch?v=F6mHaUoNpOg&hd=1Dunk Films: dunk=surfing: http://www.youtube.com/watch?v=oAp_z9fVyMQMay 2011 Dunk Mix: http://www.youtube.com/watch?v=z7MYrl716-kMay13-2011 Nice dunk session: http://www.youtube.com/watch?v=73BhhFenp7o&feature=player_embeddedAPRIL 2011 DUNK RECAP/MIX: http://www.youtube.com/watch?v=VuPS1Sm10dsSome hard freakin` dunks: http://www.youtube.com/watch?v=3nukAo_IizA , http://www.youtube.com/watch?v=QU7URZQ3Y4U , http://www.youtube.com/watch?v=FMQo64DzV70WHO RUN IT DUNK MIX - PART 1: http://www.youtube.com/watch?v=xypWSL5YVEwadarq.org commercial #2: http://www.youtube.com/watch?v=QBYlngDcxFY = if at first you don't succeed, AMP THE F UP & TRY AGAIN. lion swag dunk mix: http://www.youtube.com/watch?v=hhyqcL4fO-gmisc dunk footage from 2/20/2011, gettin` up: http://www.youtube.com/watch?v=XhF8F43z5Ogend of 2010 dunk session: http://www.youtube.com/watch?v=P2fwJ8e5Vs8The "I think i'm dying dunk mix" : http://www.youtube.com/watch?v=XiXkdX5QLNo |
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vag
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« Reply #6 on: December 26, 2009, 01:57:41 pm » |
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As i expected , i busted that hangtime calculation shit: |
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« Last Edit: September 21, 2010, 01:55:35 am by vag »
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adarqui
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« Reply #7 on: December 27, 2009, 08:07:06 pm » |
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interesting.. what was 'almost flat foot' as the starting point.. ? should be pretty close.. cool vid. peace |
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"Now Cornell University neurobiologists, studying the adrenal glands of rats, have discovered how chronic stress cranks up the intensity of this adrenaline response. The key to this so-called molecular memory resides in a donut-shaped protein on the surface of cells that secrete adrenaline, the hormone also known as epinephrine." PED's in drug free sports is cheating, unethical, and weak. Athletes and/or coaches who condone/display this behavior can get lost."But you have never felt the burn that you get in the hip flexors from pulling back on the pedal stroke, you have never done the exercise in your life. Squatting ain't doing shit for your hip flexors blu." -- sickenin vendetta. QuickMix: Gulf Dunk Mix: http://www.youtube.com/watch?v=9PHyFdbJnrY&hd=1The Promise Dunk Mix: http://www.youtube.com/watch?v=Ed5VRE0lOXU&hd=1Ballet Dunk Mix: http://www.youtube.com/watch?v=pI_c2dz0C_4&hd=1BoingTerd Dunk Session: http://www.youtube.com/watch?v=F6mHaUoNpOg&hd=1Dunk Films: dunk=surfing: http://www.youtube.com/watch?v=oAp_z9fVyMQMay 2011 Dunk Mix: http://www.youtube.com/watch?v=z7MYrl716-kMay13-2011 Nice dunk session: http://www.youtube.com/watch?v=73BhhFenp7o&feature=player_embeddedAPRIL 2011 DUNK RECAP/MIX: http://www.youtube.com/watch?v=VuPS1Sm10dsSome hard freakin` dunks: http://www.youtube.com/watch?v=3nukAo_IizA , http://www.youtube.com/watch?v=QU7URZQ3Y4U , http://www.youtube.com/watch?v=FMQo64DzV70WHO RUN IT DUNK MIX - PART 1: http://www.youtube.com/watch?v=xypWSL5YVEwadarq.org commercial #2: http://www.youtube.com/watch?v=QBYlngDcxFY = if at first you don't succeed, AMP THE F UP & TRY AGAIN. lion swag dunk mix: http://www.youtube.com/watch?v=hhyqcL4fO-gmisc dunk footage from 2/20/2011, gettin` up: http://www.youtube.com/watch?v=XhF8F43z5Ogend of 2010 dunk session: http://www.youtube.com/watch?v=P2fwJ8e5Vs8The "I think i'm dying dunk mix" : http://www.youtube.com/watch?v=XiXkdX5QLNo |
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vag
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« Reply #8 on: December 28, 2009, 03:19:22 am » |
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interesting.. what was 'almost flat foot' as the starting point.. ? should be pretty close.. cool vid. peace Flatfoot to touchdown hangtime was also wrong, its too early. The correct timeframe start seemed to be somewhere the 1st and 2nd visible heel elevation. Cant make any rule out of that. What seems to be true is that the hangtime calculator measures the highest touch - reach on your toes. So the error is equal to the flatfoot/toes reach difference, as i was speculating on my first qm. That is indeed 5'' for me , makes sense. |
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Adam.
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« Reply #9 on: March 10, 2010, 01:05:34 pm » |
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What is strange about this is that the just jump mat via it's patent filing uses a standard hangtime calculator, yet, it consistently reads slightly higher than what my vertec jump is when I measured them simultaneously. From your video, I should have seen a drastic decrease in my vertical, yet I saw a slight bump. |
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vag
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« Reply #10 on: March 10, 2010, 01:15:43 pm » |
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What is strange about this is that the just jump mat via it's patent filing uses a standard hangtime calculator, yet, it consistently reads slightly higher than what my vertec jump is when I measured them simultaneously. From your video, I should have seen a drastic decrease in my vertical, yet I saw a slight bump.
I thought of that too. I can only speculate this: jumpmat , through getting readings all the time, starts timing not from take-off ( when force is 0 ) but from the peak of the force applied. That would probably be with feet still on the ground. Maybe my correction speculation ( correction = toes up reach - flatfooted reach ) is wrong , and the correct correction is that. Or maybe ( i highly doubt that ) it just uses some standard correction like 5'' which would be correct in more cases but not in all. Anyway i was not refering to jumpmat , im sure its pretty accurate , i was refering to counting time/frames in the air and calculating your jump from that with the hangtime calculation... |
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