Author Topic: Biomechanics in Parkour  (Read 23933 times)

Steez

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Re: Biomechanics in Parkour
« Reply #20 on: October 20, 2006, 09:55:38 PM »
maybe the biomechanical effects of different vaults on the body...like the force exerted on a flat surface by a kong, and about how much of it goes into the shoulder joints, etc.

Offline like_a_child

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Re: Biomechanics in Parkour
« Reply #21 on: October 20, 2006, 09:57:29 PM »
Maybe you could test the difference between the angle of a landing and the speed of your take off? I can't really explain it right now because I'm so tired... BRAIN NUMBING!!!!

I'll take a stab at this one . . . if you hurl yourself forward in a low leap, the landing is already partially horizontal, and helps you roll; but if you move slowly, you give gravity more time to turn your descent into a fall straight down.
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Offline Andy Animus Tran

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Re: Biomechanics in Parkour
« Reply #22 on: October 21, 2006, 09:40:26 AM »
I'd also like to see video of you trying to stop your knees from going past 90 since that's the biggest crock and piece of bad info in the PK community, I'm quite sure if you lock your quads to do that, more force and shock will go through your body than if you go to natural flexion.


Whoa, whoa, whoa...  I don't think you understand the 90 degree thing.  For a striaght drop, there isn't a soul out there who believes going past 90 is bad for you.  It's very similar to a full Olympic squat, and the force and weight are placed on anatomically similar points.

However, in trying to preserve forward momentum, that's different.  You said before that the purpose of a roll is transfer downward momentum into forward, as well as to alleviate your knees from taking the pull downward impact through that displacement.  The "no-90 degree" land has the same purpose, but because the downward force isn't enough to necessitate a roll (i.e. you will not cause too much damage from taking the drop straight), the primary purpose becomes merely to preserve forward momentum; hence, you have the body going forward before the knees bend past 90... hence, you have the hands coming to the ground furhter away from the body, the pushing off to displace the momentum, and to continue running forward.

If you want Demon to test the 90 degree rule, then you MUST consider it in the situation of a FORWARD leap continuing forward momentum.  That is its purpose.  Otherwise, a leap with forward momentum into a land that bends past 90 and then continues to IMMEDIATELY upon landing move forward... I believe that is where you will cause unneeded stress on the knee.  It's very similar to the idea of a depth jump (conditioning exercise), except more dangerous.

However, I think the machinery needed to determine stresses on isolated parts of the bodies (knees vs. ankles) would be needed to test these kinds of things, since when you're just measuring straight impact overall, it's going to generally be the same.
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Offline bigninjapimp

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Re: Biomechanics in Parkour
« Reply #23 on: October 21, 2006, 08:32:22 PM »
Also, if have alot of forward momentum and you dont roll, you slam your upperbody and face into the ground and put a huge impact on your wrists. Rolling just neutralizes this force.

Offline Valigon

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Re: Biomechanics in Parkour
« Reply #24 on: October 22, 2006, 07:05:57 PM »
If you learn anything about the physics of rolling to spread the kinetic impact of landing across the time axis (sorry, I'm picturing a graph here that models the landing), please let us know!

i can tell you this after taking high school physics...
you have 3 variable
F = force
V = velocity
T = Time
the equation is
F=V (final) - V (inital) / T

So basially this means that the longer it takes you to slow down the less force you will feel. and yes you actualy do slow down, when you are landing.. you are slowing down to a stop actualy (in the Y - axis) while maintaing velocity in the X-axis. so by adding a roll to a landing you effectivly increase the time it takes to stop in the X axis decreasing the force you feel, and efectivaly making it softer (this is the same reason why you have pads in football, and crumple zones in cars)  well if i bored anyone let me know... i tend to do that....


Offline Ryan Ford

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Re: Biomechanics in Parkour
« Reply #25 on: October 23, 2006, 10:08:55 AM »
So I went to meet the prof today. He already had a good understanding of what parkour was about and turns out he saw the COPK 9news thing on tv back in september so he already recognized me from that. He thinks parkour is very exciting and is willing to help me out a lot with this stuff. He showed me the lab and it is a large room with a force measureing landing strip about 30 feet long and 5 feet wide. The actual measuring part is only about 8 feet long but it can be broken up and rearranged. The ceiling is about 10 ft. so there are height restrictions.

We did not establish the extent of which the study will be although he led me to believe he was willing to go as involved as I wanted all the way to an independent study for credit and funding grants from a sports injury organization.

Based on my observations of the lab, at least in the beginning, the focuses will probably be on straight drop landings, running to vaults to step out, 2 foot, and roll landings (can test the impact force of different landings to see what is better biomechanically), and rolls depending on if we can arrange the force measuring strip right.

We are still in talks of what all we want to test and how everything will work. I have to figure out the extent to which I want to pursue this and it will also require clearance from the university. While the university would probably not want to endorse a study on something as unknown and "dangerous" as parkour, the backing I have from this important professor should allow it to happen.

I will keep you all updated when I know more, until then, keep posting any ideas and more specific ideas of the main emphases I listed above.

P.S. He remembers you Ken. We talked about you a little bit and he didn't seem to be at all surprised that you were into parkour. ;)

Offline Jumpin Jiminy

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Re: Biomechanics in Parkour
« Reply #26 on: October 23, 2006, 11:39:12 AM »
Trying to understand the difference between energy expended for a box jump up as that disipated into the feet/ankle/leg during a depth/tuck/quad/roll landing.
The ratio might suggest the maximum safe height to jump down from.

Offline Zeus

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Re: Biomechanics in Parkour
« Reply #27 on: October 23, 2006, 01:19:24 PM »
Also I dont know if this is possible (or if its too late) but measure the force put on your hands during different vaults

Offline Nik "Nik" Horvat

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Re: Biomechanics in Parkour
« Reply #28 on: November 21, 2006, 08:22:00 AM »
Any new developments on this front?

Also, from what I know of physics(only class I got >100% in in HS and college)  the 'x' and 'y' axis are seperate.  Meaning that your forward momentum doesn't change the amount of force in your vertical fall.  A bullet falls at the same speed along the y-axis regardless of whether you drop it or its fired out of a gun.  Though I'm not sure if a roll increases the time component of a landing compared to a strait fall(ex. it gives you a greater amount of time to slow down). 
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Offline Ken PKChiro

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Re: Biomechanics in Parkour
« Reply #29 on: November 27, 2006, 09:24:14 AM »
yep, i have my graduation pic with roger kram.  yeah, i thought he already knew i was into parkour.  in the force plate studies, i was always the guy jumping up and down on the plate.  from my initial observations, landing flat footed, with no knees bent would increase your vert force impact to 3 times your body weight.  while bending your knees you could reduce it to about 1.5 your body weight from a straight jump up.  yeah, there isn't much space to use.  is he going to let you use the big force plate?  maybe this summer when i head back i can come and help out with the study.  (kram was a while back considering doing a study on running in a complete loop like a skateboarding loop thing, and he wanted me for the study haha, prob why he remembers me.)  anyway, he's a good guy.  wish i were there
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Offline Ryan Ford

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Re: Biomechanics in Parkour
« Reply #30 on: December 13, 2006, 01:49:12 PM »
Update:

I have gotten clearance to do a 3 credit independent study on the biomechanics and exercise science of parkour for next semester. I will have access to force measuring impact plates, obstacles, high speed cameras and motion capture (the same stuff you see people wearing to capture motion for video games), and even more stuff to be determined. I am sponsored by the head professor of biomechanics at CU. He is one of the top 10 experts in the world on the biomechanics of running.

I will be exploring and characterizing the biomechanics of parkour as well as compiling information and guidelines on the levels of fitness and skill required to do parkour movements safely. My final projects will be an extensive final paper on the findings and/or a video/powerpoint presentation.

This is still a pretty open study and we don't have much set in stone. It will most likely evolve over the semester so I'll keep you all updated.

Ken - yeah i have access to pretty much everything. he told me about the loop also. they are having problems setting up a safety harness to have people test it. matt says he will do it though, haha. yeah it would be cool if you were here to help. you could still help with the brainstorming and development process.

Offline Steve Low

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Re: Biomechanics in Parkour
« Reply #31 on: December 13, 2006, 07:21:43 PM »
Any new developments on this front?

Also, from what I know of physics(only class I got >100% in in HS and college)  the 'x' and 'y' axis are seperate.  Meaning that your forward momentum doesn't change the amount of force in your vertical fall.  A bullet falls at the same speed along the y-axis regardless of whether you drop it or its fired out of a gun.  Though I'm not sure if a roll increases the time component of a landing compared to a strait fall(ex. it gives you a greater amount of time to slow down). 

While this is true, the physics of rolls DO divert y momentum into x momentum. Think about dropping a ball vertically straight down onto a surface that is 45 degrees. It will bounce off that surface and go whichever way it is slanted at a pretty quick rate depending on how far it dropped. This concept is the same one with rolls as the feet act as a sloped surface for the body to convert vertical momentum into horizontal momentum. The better the roll (e.g. the better conversion of momentum from y to x axis), the less vertical momentum is on your joints which is good. However, obviously there will be some friction with you and the ground in the x direction so I'm not sure how much that plays into it. With an efficient roll though the friction won't hurt you though.

--------------------------------

Nice Demon.

Are you going to do stuff at like different heights and/or try to get different people rolling in there to see the efficiency of some of the people's rolls or what? :P Keep us updated.
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Offline Ryan Ford

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Re: Biomechanics in Parkour
« Reply #32 on: December 14, 2006, 11:21:41 AM »
I've posted this on other forums now that it is deifnitely going to happen:

I am a student at the University of Colorado at Boulder, one of the top research universities in the USA. Recently I contacted the integrative physiology department in hopes of working with them on some quick parkour studies. Initially I was just looking to put together a short but valuable presentation on some impact data to demonstrate the fitness and conditioning levels needed to practice parkour safely. Instead, the head biomechanics professor, who is also among the top 10 experts on the biomechanics of running and jumping in the world, has taken great interest to my proposals and has sponsored me to do a full semester independent study on the biomechanics and exercise science of parkour.

We have just begun preparing and brainstorming everything we want to do and these are our main (and very general) goals so far.
______________________________________

Objective #1 – To characterize the biomechanics of basic movements and techniques in parkour.

Objective #2 – Determine the strength, flexibility, endurance, and skill of experienced and inexperienced parkour practitioners. To establish the basic levels of fitness required to safely perform different parkour movements at different scales of size

Question #1 – How great are the biomechanical loads on the body during parkour?

Question #2 – What physical abilities distinguish parkour practitioners?
______________________________________

The biomechanics professor will be helping me along the whole way and most likely, the head exercise science professor will become involved later on. I will have access to force impact plates, a force impact runway, high speed cameras and motion capture equipment, and other exercise science equipment to be determined.

So essentially, the sky is the limit and my only constraint is time (I will be able to put in about 6 hours a week).

As far as I know, this will be the first formal parkour science study ever done (aside from Danno's brief investigation into landings impact) and will hopefully result in a lot of useful information to increase safety awareness of parkour. My goal is to put together all of my info and findings into a organized final paper and video or powerpoint presentation that will be then made available online for everyone in the parkour community to refer to.

Again, we are still in the very early stages of planning and while we have a lot of ideas on what we want to do so far, I am open to and seeking out other traceur's suggestions on what they want to see done with this study. As the semester approaches and goes by, this study will likely evolve and change over time as we get more ideas and results.

So post up any comments, suggestions, or questions you have and I will do my best to address them in the study!

Demon

Offline Tsumaru

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Re: Biomechanics in Parkour
« Reply #33 on: December 14, 2006, 07:29:01 PM »
Enter the delayed reply!

Quote from: Animus Light
Whoa, whoa, whoa...  I don't think you understand the 90 degree thing.  For a striaght drop, there isn't a soul out there who believes going past 90 is bad for you.
Are you sure?
http://parkour.net/parkour/newbb/viewtopic.php?viewmode=flat&type=&topic_id=4846&forum=5
Quote from: andi
leaning forward or not has NOthing to do with this. whenever the knee joints get bent more than 90 degrees, they are weak. your body position doesn tmatter, if you are in outter space and your head faces the ground, its still bad for them. you shouldnt bend further than 90 degrees, if you do, you shouldnt put full power pressure anymore after the first 90 degrees. simply.

btw if you didnt know.. i came up with the 90 degree rule for parkour, so if you have any questions about that, you can ask me on msn, no need to take the risk to have people like the panther answer you on the forum with bad and dangerous advice
I didn't know andi came up with the 90 degree rule, but right now I think I want to kill him. Regardless..
Quote from: Jaho101
Personaly I need to start living by the 90 degree rule. My only issue is the slight straining of the back muscles after a few hardcore hours of training. Also because of the lack of the 90 degree rule in my life, I think I managed to screw something up in my knee and every time i take a step now, there's a slight pop feeling (not a noise, I just feel it).
Oh noes, Andi recruits!
And certainly there are other posters in that topic backing him up.

http://parkour.net/parkour/newbb/viewtopic.php?viewmode=flat&type=&topic_id=3674&forum=5
Quote from: Zorak
no...second way is the best way

you dont harm your legs(you harm your legs with every drop) but you dont harm them when you dont let your knees get infront your feet and dont bend them more than 90 degrees

and using your arms helps to transmit the shock on not just the legs but on the whole body
Quote from: Scott
try not to bend your knees past a right angle. or you can strain them. keep them almost 90 degrees and absorb the rest of the shock with your arms.


These are just a few I found quickly. Exclusively on parkour.net I know, but I knew that I could rely on quick examples there. So anyway. Animus Light, you really need to readdress your statement that there's not "a soul out there who believes going past 90 is bad for you". Clearly, there are souls, in fact - quite a few souls. So, in this regard, I'm definitely with M2. I want this crap cleaned up. In fact, I've already been finding studies in regards to weightlifting to refute this, but this one could help a lot since it's specifically Parkour. What we want to look at is the degree of force on the patellofemoral joint at various angles of the leg during a landing. That's what I really want. Awesome work Demon. =)

Offline Steve Low

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Re: Biomechanics in Parkour
« Reply #34 on: December 15, 2006, 09:17:13 AM »
Landings are a whole different ball game than ass to the grass squats... The latter is where there has been lots of debate in the weightlifting community. I am of the opinion that past 90 degrees all the way to the ground is good as long as you don't take tension off your knees at the bottom. Hell, all those oly lifters do it and they almost never have knee problems which means with good form they are excellent.

Landings, on the other hand, because of the plyometric nature of the movement can be a bit debatable especially landing in compromised knee positions with the heels off the ground. This should be one of the areas you look at.
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Offline whiteninja

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Re: Biomechanics in Parkour
« Reply #35 on: December 15, 2006, 01:10:00 PM »
I'll be eagerly awaiting to see your paper, Demon.



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Offline Andy Animus Tran

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Re: Biomechanics in Parkour
« Reply #36 on: December 15, 2006, 06:44:02 PM »
Tsumaru, I was unaware of andi's description of it...  which I think is frankly stupid.  We're built to use our range of motion.  However, it has always been my understanding that the "90 degree rule" applies to drops with forward momentum, not straight downward drops, and is in effect mostly due to the fact that going beyond 90 degrees kills your forward while not going beyond 90, leaning over, pushing off with your hands, is more effective to maintain the forward momentum (hence going beyond 90 degrees is great for precisions).  In any case, that's MY 90-degree rule and the way I've seen most people defend it.  Thank you for clarifying that there are people out there who believe that any movement beyond 90-degrees is detrimental.  It is news to me.
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Offline Ryan Ford

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Re: Biomechanics in Parkour
« Reply #37 on: December 15, 2006, 07:15:56 PM »
My interpretation of the 90 degree rule is that full range of motion is fine unless done with force. going past 90 degrees with force is uncontrolled and can injure your knee. this happened to me one time on a really tough kong to same level precision in which i landed to scrunched up and suffered a knee sprain.

Offline Tsumaru

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Re: Biomechanics in Parkour
« Reply #38 on: December 15, 2006, 07:54:14 PM »
Animus Light - I personally agree with you that going beyond 90 degrees kills forward momentum and so shouldn't be done for that purpose, but there are people who seriously believe that it is inherently dangerous. That is what I have issue with. Especially since with a straight-drop going beyond 90 gives you more room for cushioning, which is vital if it's a drop of significant height (not that I am advising people do such a thing, of course <_<).

Steven L - I agree that it might be different with landings, which is why I said that despite the studies in the weightlifting community, a study specifically for Parkour landings would be a lot more beneficial and valid.

Demon - When you started landing on the bar, were you already considerably scrunched up? If so, that would be akin to landing with your knees already bent most the way and is obviously a bad idea. If you did have a full extension of the legs originally, I'm not so sure. Perhaps the direction of force while landing a kong to precision is considerably different to just a straight-drop and becomes relevant in potential injury? Just hypothesizing here though. I've not done a kong to same level precision so don't really know how it feels.

Offline mmuir

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Re: Biomechanics in Parkour
« Reply #39 on: December 16, 2006, 06:32:09 AM »
hey demon, can you try finding out how much momentum you get from falling...instead of force from landing,the nmaybe you could link the momentum and force of impact to a formula, and find out how much a body can take(yours im sure it's different for everyone because of weight, muscle, bone mass) and figure out how bad you can hurt yourself and how much you could avoid hurting yourself...just a thought...and the landing and roll landing sound great!
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