Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

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willrieffer
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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby willrieffer » Thu May 29, 2014 8:10 am

PVstudent wrote:I am still baffled that despite the dangers and obvious violations of the first principles of force application in (over)bending the pole whilst in ground contact at take-off he even wants to search for " a holy grail" solution to the problems created in the subsequent pole support phases of Dossovi's vaults. Like another ugly duckling vaulter in his early years Dossevi may eventually turn into a swan to become elegant(style) and efficient(technique). So time will tell and I never say never!

I hope that if Will is really on to something of value that has been missed by the greatest coaches (USA, France, Germany, Russia) on the planet during the last 50 years that he is able to enlighten us.

Give me a few days and I will try help Willrieffer to clarify for us what he is talking about. I admit I don't get what he is driving at?


Since I mostly see this in a bunch of French vaulters where I look at them and ask, "What are the physics repercussions of what they are doing?, I have doubts that I'm really on any cutting edge theory but are instead revealing what someone else has already figured out. The question is perhaps whether its implicit or explicit. Dossevi was obviously not following the PB. I might fathom a guess that somehow he became a guinea pig for someones ideas (possibly his own!), that have found their culmination in some form of superimposition with the PB model in Lavillenie.

But then most of my ideas came from watching beginners fail. And most coaches know that they must steer their athletes away from obvious detrimental effects and how. Lots of coaches. The question is do they know why? Could they take such an idea to its logical end and physical extremes where there are elements of real danger? And with that we're back to the French where someone once told me they called Dossevi, "the pole tester"....

Will

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby willrieffer » Thu May 29, 2014 8:54 am

vault3rb0y wrote:The goal is not to compress the pole. The goal is to move the pole the vertical.

Otherwise the higher gravity is, the better. And that just makes no sense. In your theoretical equations, vaulting on the moon would yield lower jumps than vaulting on earth.


Neither statement holds to physics. If moving the pole to vertical is the goal, then one way to achieve it is through chord shortening through its only means, compression.

"the higher the gravity is, the better"...

Well, only for one guy though...

"vaulting on the moon would yield lower jumps than vaulting on earth"

Not necessarily, and not in reality. If you meant to say that such a change in the gravity field would again cause a variance in the two vaulters, that would be correct, but it does not necessarily follow that they will vault lower because of the change.

Or, yes, gravity variance would modify the way you would want to vault on many levels...

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby altius » Thu May 29, 2014 9:19 am

Will old son - I am now certain that you are a simply prankster with nothing better to do than to spend your time checking out how seriously folk will respond to the rubbish you write. The level of ignorance you are betraying is so astounding that it cannot be what you actually believe! Come on, come clean and tell the truth - April 1st is long past.
Its what you learn after you know it all that counts. John Wooden

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby willrieffer » Thu May 29, 2014 9:37 am

altius wrote:Will old son - I am now certain that you are a simply prankster with nothing better to do than to spend your time checking out how seriously folk will respond to the rubbish you write. The level of ignorance you are betraying is so astounding that it cannot be what you actually believe! Come on, come clean and tell the truth - April 1st is long past.


Not enough information for me to, well, do anything with. Sorry.

Just another personal assessment.

Real PV or physics conversations between Will and Altius. Zero. Keepin the tally high...

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby KirkB » Thu May 29, 2014 12:53 pm

vault3rb0y wrote: The goal is not to compress the pole. The goal is to move the pole the vertical.
:yes:
AND to raise the CoM as high as possible (and to clear the bar). To me, this means to raise the CoM as QUICKLY as possible.

It sounds like what Will is observing (not necessarily advocating - but trying to explain mathematically) is that Lavillenie is purposely keeping his CoG low (by dropping his lead knee and by pushing up with his bottom arm). And then, through an amazing rock-back (rocking back futher than most mere mortals by putting one knee on each side of his bottom arm), he allows the pole to rotate to vertical, and gets into good position to do an excellent extension.

I also observe this when I watch him vault in his vids. So to me, Lavillenie seems to be breaking all the rules defined in Agapit's Theory of Continuous Motion.

I don't think we should be criticizing Lavillenie's technique here. This will only lead to the conclusion that (since he's not following the Petrov Method after he leaves the ground) he's doing it "wrong" or "inefficiently". Rather, I think we should be striving to UNDERSTAND Lavillenie's technique.

To us Petrovers (that pride themselves on following the Laws of Physics), his technique on the pole seems counter-intuitive. Yet there have been many 6.00m vaulters prior to Lavillenie that succeeded with this technique (the exception being that we now know that Lavillenie INTENDS to have a free takeoff, whereas most of his predecessors with similar technique INTENTIONALLY took off under).

So HOW does he do it? I think this is what Will is trying to determine, and it's certainly what I'm interested in knowing.

I think that unless we take our Petrov hats off, and until we set aside (until we figure this out) our current understanding of the Laws of Physics, we won't reach a clear (mathematically proven - according to the Laws of Physics) explanation of what he does on the pole (or why he does it, or why it's successful.

Let's put our heads together and figure this out. More science, less head-to-head bickering about why his technique is sub-optimal. Nobody's perfect - not even Lavellinie or Bubka, but that's not the question.

To me, the question is: From a scientific perspective, how has he been able to achieve his WR level of perfection? :confused:

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby KirkB » Thu May 29, 2014 1:15 pm

KirkB wrote: ... Lavillenie is purposely keeping his CoG low (by dropping his lead knee and by pushing up with his bottom arm). And then, through an amazing rock-back (rocking back futher than most mere mortals by putting one knee on each side of his bottom arm), he allows the pole to rotate to vertical, and gets into good position to do an excellent extension.

Is everyone seeing that extra "push" with his bottom arm in an upwards direction after he (apparently) pauses in his low-hanging position? It's kind of a "push-pause" - maybe timed in unison with the bounce of the pole?

I'm thinking that might be what he does differently than his predecessors (other than the free takeoff thing)?

What do you all think about this?

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby PVDaddy » Thu May 29, 2014 11:19 pm

Kirk Wrote:
It sounds like what Will is observing (not necessarily advocating - but trying to explain mathematically) is that Lavillenie is purposely keeping his CoG low (by dropping his lead knee and by pushing up with his bottom arm).


I won't speak for Will, but, I believe that what he means by taking better advantage of the gravity vector as early as possible and for as long as possible he is in fact advocating it's potential advantage and I concur.

My opening line while attempting to describe " Lavellenies Model of pole vaulting " under that thread:

From the very beginning of Plant and going into take-off and into swing I believe Lavellenie makes every effort possible to keep his COG as low as possible. That begins with a wider hand spacing to help keep his hips and torso back and low.


and:
Like I said he has no knee drive and in fact lowers his drive knee to match his swing foot while at the same time fully extends his left hand which together make his swing path and COG as low as possible. His bottom hand never goes over his head or has to be re-extended like Bubkas during vaulter/pole loading to lower it. His COG is immediately as low as possible and earlier on in his swing than Bubkas so he takes advantage of the gravity vector earlier illustrated by his immediate and more severe pole bend. Will points out the importance of the gravity vector in this statement and I believe it captures the essence of Lavellenies success:

It is therefore beneficial for the vaulter to try and have gravity compress the pole more and effect their swing less by braking the swing into the pole and present a better relation to gravity for as long as possible.



Lavellenie assist and maintains this perpendicular to gravity position by a wider hand spacing and a full extension of his bottom hand and the lowering of his drive knee to match his swing leg and by this time the vaulter/pole system is fully loaded with the COG immediately as low as possible. Much earlier in the swing than the PB method.


Kirk Wrote:
I also observe this when I watch him vault in his vids. So to me, Lavillenie seems to be breaking all the rules defined in Agapit's Theory of Continuous
Motion.


and:
Is everyone seeing that extra "push" with his bottom arm in an upwards direction after he (apparently) pauses in his low-hanging position? It's kind of a "push-pause" - maybe timed in unison with the bounce of the pole?


Yes, I see an obvious push and extension of his bottom arm and believe it occurs immediately after Vaulter/Pole system loading. His bottom arm is bent prior to this to top hand load. I believe his intent is to keep himself as far away from the pole as possible (He extends his bottom hand to the max), to keep his COG as low as Possible and for as long as possible. He maintains this all the way through to his tuck. I also see him making every effort possible to keep his body load on the top hand all the way to his tuck.
I personally do not believe he is breaking the rules of continuous motion. I believe with his tuck, if he did, he would find it impossible to get ahead of the unbending pole in time and get on top of it (This is already a problem that most all tuck and shooters have). Lavellenie gets on top. I believe Will also sees a delay, but, I have looked hard and long and just can't see it? Perhaps it is something you more experienced vaulters have a sense for recognizing? I Just don't see it or believe it is beneficial or his intent for reasons mentioned.

Kirk:
I don't think we should be criticizing Lavillenie's technique here. This will only lead to the conclusion that (since he's not following the Petrov Method after he leaves the ground) he's doing it "wrong" or "inefficiently". Rather, I think we should be striving to UNDERSTAND Lavillenie's technique.
:) :yes:

I would take it a step further and at least be open to the idea that it may in fact be more efficient.

Kirk:
To us Petrovers (that pride themselves on following the Laws of Physics), his technique on the pole seems counter-intuitive. Yet there have been many 6.00m vaulters prior to Lavillenie that succeeded with this technique (the exception being that we now know that Lavillenie INTENDS to have a free takeoff, whereas most of his predecessors with similar technique INTENTIONALLY took off under).


I believe it seems counter-intuitive to Petrovers, because, it is such a radically different approach during pole support. He immediately going into take-off and through his take off, takes the low path were I believe Bubka on the other hand takes the high Path. Who gets to Scotland First? LOL.
I believe he does follow the laws of Physics, but, just takes advantage of them a different way. This is what Will and I have been attempting to explain.

Kirk
:I think that unless we take our Petrov hats off, and until we set aside (until we figure this out) our current understanding of the Laws of Physics, we won't reach a clear (mathematically proven - according to the Laws of Physics) explanation of what he does on the pole (or why he does it, or why it's successful.
:) :yes:

I believe Will understand the laws of Physics much better then most are giving him credit for here. I also believe he understand how this agrees with the current understanding of the laws of Physics, but, I do not think the Pole vaulting's community has yet come to this understanding as his approach is in many respect is quite innovative and in some ways unique.

Will, In simple terms, would you agree that Lavellenie simply takes advantage of the gravity vector better, by keeping his COG lower much earlier in the take-off and swing and for a longer duration of his swing, which provides an earlier and more efficient bend in the pole?

What are others thoughts on this that I mentioned in My attempt to explain in my Lavellenie Model of Pole Vaulting thread:

I believe he has a very flat take off and basically just runs under the pole with a minimum of jumping effort or knee drive. This means he has no breaking effect from transitioning into a jump and therefore tremendous vertical (I meant to say Horizontal) velocity going into take off and therefor a great amount of force is immediately applied to the pole from his top hand.


Would not this also help to keep his COG lower immediately? Is it possible that although Lavellenie is slower then Bubka, he makes up for this velocity by a lower loss of it because he experiences little to no Braking effect as he transition to take off?

any thoughts on this?

From the moment the foot leaves the ground the flexible pole (for a right handed vaulter) immediately begins leaning to the left and bends to the left. This creates a larger window to swing through that the stiff pole did not nearly offer (Earlier stiff pole vaulters had to learn more how to swing around the pole). This left bend is sever but in Lavellenies case it is even more sever earlier on. This has a major effect on the physics of the vaulters swing path. As it is giving way left it causes the vaulters swing path to be oriented in that direction rather then perpendicular. To compensate for this, the wise vaulter steers their swing path to the right and up or toward the top hand. This is necessary in order to create a perpendicular swing. Altius, I have just answered for you why and how the sideways pole bend effects the Physics of the vault. Because Lavellenies pole bend is more sever and earlier on he compensates by orientating his swing path even more so to the right then Bubka's to the point his take off foot swings well more past the right side of the pole then Bubka's and I believe it is possible this counter side swing achieves better counter thrust bend to the pole at the top of his swing as well?
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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby PVDaddy » Thu May 29, 2014 11:53 pm

Forgot this.

Kirk: And then, through an amazing rock-back (rocking back futher than most mere mortals by putting one knee on each side of his bottom arm), he allows the pole to rotate to vertical, and gets into good position to do an excellent extension.

What Wan described as "The Ball".

Here is what I said:
He simply goes from from a very low COG vaulter/Pole system loading swing path position to an immediate double leg swing (Frog like) into an immediate tucK (a ball) with both thighs and knees at each side of his hips while throughout the entire swing makes a concerted effort to maintain a leaned back position on the top hand for maximum pole bend.


I should have also mentioned that he also makes ever effort to keep his body as for away from the pole throughout his swing even while in "The Ball".
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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby KirkB » Fri May 30, 2014 1:09 am

PVDaddy agreeing with me? :confused: What is this world coming to? :dazed:

Nothing I've said so far, and nothing PVDaddy has said so far is earth-shattering. We can all see on Lavillenie's vids WHAT he's doing.

The big question is: How is it possible that he does what he does?

Unless you've been there and done that, you can't possibly imagine how difficult it is to stay low (delaying your swing), and STILL get inverted in time for a good extension. It's no secret that how a tuck-shooter keeps the poll rolling forward (something that a delayed swing and bottom arm press normally inhibits) is to get into an ultra-rockback (knees on each side of the bottom arm).

But this is MUCH more difficult to do than to say. It is so difficult that this is where most high school and college vaulters fail - they waste too much time in the early part of their "swing" (which is more of a row than a true swing) that they have no time left to get into an ultra-rockback. Thus, they flag out, and never reach their full potential.

There are exceptions to this predicament - some American and some French (and other European, and a couple of South African) vaulters were able to cope with this. It's just that they didn't have a free takeoff, and were preloading the pole before takeoff (highly inefficient, despite some success by some athletes that were athletic enough to vault 6.00m in their sleep).

But all I'm doing (as has PVDaddy) is state the obvious. We STILL have not gotten any further to understanding how this makes sense from a physics perspective. We know that Lavillenie obeys the Laws of Physics (another obvious statement). We just haven't broken it down yet into some scientific forumula or reasoning that makes any sense. At least not to anyone that's focused on the Petrov Model for most of their life.

I'll bet Tim McMichael can give us some insight into this. While not exactly like Lavillenie's, his technique had some similarities - especially how to get back quickly into an ultra-rockback to keep the pole rolling.

In the past, I have commented on the double-leg swing technique of Wofgang Nordwig (winner of the 1972 Olympics) who I vaulted against. In those comments, I stated that I could not see how he could get inverted early enough for a good extension. Yet he beat Bob Seagren and Jan Johnson that year.

I had already eliminated his technique as a possibility for myself a couple years earlier, because I considered what he was doing as highly inefficient - much more of a muscle-up (in my eyes) than a proper swing. I don't recall at this moment (I'd have to check my previous posts or his vids), but I THINK he had a free takeoff.

Fast forward 42 years, and here we still are. The double-leg swing still has success at the elite level! I don't get it!

Tim?

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby KirkB » Fri May 30, 2014 1:14 am

In another thread, Tim posted this:
Tim McMichael wrote:A double leg swing lowers the vautler's COM. That factor outweighs having a shorter trail leg unless the trail leg is very long with a very powerful swing, in which case it is a wash, in my experience. I jumped just as high both ways, and I have seen so many high jumps with a double leg swing and without one that I regard it as a style difference and not a fundamental element of the vault.

Can you expand on this Tim? What's a wash? Thanks.

I don't see this as a simple style difference, because it changes the tempo of the swing so much, because it's MUCH easier to single-leg swing to an invert than to double-leg swing. Isn't it? :confused:

Maybe part of the answer is that it's not as hard as I think, if you've trained all your life with a double-leg swing? I don't know about Nordwig, but Lavillenie was a gymnast (he did acrobatics on horseback), so maybe the double-leg swing came much more naturally to him than a non-gymnast?

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby willrieffer » Fri May 30, 2014 9:08 am

vault3rb0y wrote:The goal is not to compress the pole. The goal is to move the pole the vertical.


As Kirk points out, the goal is to vault high, achieve max height. Moving the pole to vertical certainly helps this. Certainly. But I feel vault3rb0y is moving into the area of intent versus the actual. In modern vaulting we know that PB vaulters don't concern themselves with achieving pole bend or compression, yet their poles still bend and compress from the forces on them. So we still need to think about compressing levers. I would think that since we are dealing with a double pendulum system everyone here would understand pendulums and rotating lever properties, but apparently there is still some fog about the subject...

Short pendulums/levers rotate faster if they contain the same amount of energy. Since most pendulums work with gravity as the accelerating force from a potential energy starting point, the longer the pendulum the slower it moves. You might want to think about a figure skater who starts a slow spin with their arms and legs extended and by pulling in their arms and legs spins faster. Now, at least from one perspective the vault is the manipulation of two pendulums, the pole and the vaulter, to achieve max effect.

Compressing the pole, shortening its chord, makes it move forward faster, or rotate faster, and thus helps move it to the vertical. It's just physics that we can witness and see in many objects and has been studied and documented for centuries. It's science. The force on it and its rate of compression are important. Also, because its an elastic lever, it stores and returns energy. Both are good things that have lead to the boom of WR heights since the advent of the flex pole.

Some also seem aware that its best if the vaulter presents a long lever as soon as possible in the swing. Why? Well one reason is that they are intuitively aware from years of either vaulting or coaching that if the vaulter shortens their swing, pulls up their take off leg or pulls with the arms, it kills the vault? Why? Well I've been trying to explain why. They lose compressive force from gravity. The pole doesn't shorten as much, doesn't store as much energy, doesn't rotate as much to the vertical, and they stall out. Much of my thoughts, as the depraved free thinker that I am, came from watching new vaulters fail vaults for this reason. Then I would see a fairly good HS vaulter and think, "IF they could only stay back and down on that swing for a bit longer, they could use a bigger pole/higher handgrip, and vault higher." But as has been said here by Kirk most recently, that is often easier said than done. But still, logic and science gave me an intuitive lead that if the vaulter going forward and up too fast was bad, it was probably that staying back and down was good (which I explain with gravity vector analysis), and probably more efficient. And so not long after comes Lavillenie, in whose every action I see him working to stay back and down for as long as possible, and for which he seems to be one of the few guys that can get back out on top. How does he do it?

Well, we're back to pendulums and rotating levers. Think of him like a figure skater. Initially he's long. In his case he presses the CoM by lowering his right leg, lowering his CoM, which has the same effect of moving the weight of a metronome out on its lever. It slows hims down. This already starts the problem most find (myself included) with attempting this technique. It's hard to get out. What do you have to do? Well you have to at some point time a shortening of the lever, make yourself shorter, tuck. The problem with most tuck vaulters as I see it is that they start too late and past the time when they should tuck. If you watch Lavillenie, his tuck happens early, at least in his angular rotational attitude. And its a very dynamic tuck. He changes shape fast, almost violently, which radically changes his rotational speed. Think again of a spinning figure skater. Even for them they usually speed adjust at manageable rates for if they would just all the sudden whip their arms and legs in it causes a greater chance to lose balance. Lavillenie's timing and control are almost superhuman. He gets out on top and wastes no time in extending over the pole. He's better at this than anyone has ever been. Also, by shortening himself as a lever, it gives him a leverage advantage about the shoulders. That is, he can add more efficiently to his rotational speed through muscular activity.

Take Off and Continuity

Really, I don't know. Information says he's moved to a "free take off". In some sense it matters not to me. The vaulters "hanging" angle which determines the gravity vector resolution can be paired with a free take off. Does he come off low, high? I don't know. I just know the ideas aren't incompatible. One of the things I keep trying to point out was that in the PB model they were very interested in not having the CoM thrown forward under pole braking. This was a great leap forward according to my analysis because as the CoM goes forward, as the angular relation to the top hand progresses, the vaulter loses compressive force. Lavillenie extends the process, actively.

And progresses actively through the entire vault. I see no delays. The take off is active. He activates himself into the pole with arm use, causing action/reaction with himself and the pole. The right leg doesn't pause in movement.

And one last thing. In another thread Tim makes a comment about the take off/trail leg.

A double leg swing lowers the vaulter's COM. That factor outweighs having a shorter trail leg unless the trail leg is very long with a very powerful swing, in which case it is a wash, in my experience. I jumped just as high both ways, and I have seen so many high jumps with a double leg swing and without one that I regard it as a style difference and not a fundamental element of the vault.


This reinforces my silly glee at watching Lazero Borges. That take off/trail leg action is marvelous. That he can use it so far behind him is him ever moving his CoM back during the vault while you can watch him press and repress the lead arm. Then he swings that leg back forcefully down. And so where we might characterize Lavillenie as a down and back vaulter, Borges is more back and down. Oh, but that spicy Latin run up..

http://en.wikipedia.org/wiki/Pendulum
In particular note, "Animation of a pendulum showing the velocity and acceleration vectors". Gravity is along the perpendicular line, and note the changing forces which the activity of the vaulter can manipulate...

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby CoachEric » Fri May 30, 2014 9:57 am

A lot of posts in this thread are written as if the prevailing assumption is that Lavillenie or his coaches made some concerted effort to develop a unique model in order to simply "crack the code" to beat 6.15. Well, that's obvioulsy ridiculous, and I think that a lot of folks are seeing differences in style that are not materially relevant to performance.

I asked David Butler once about his former athlete Jason Colwick, whose double leg swing is a bit more unconventional: http://youtu.be/sOBAV8HLVEc

He said that when Jason first came to him, he went to Petrov to ask his opinion on the swing. David, in his best Petrov accent, said that his answer was, "the swing is not in the feet - it's in the hips!" Petrov was saying that in his opinion, the legs don't really matter. In my opinion, the double leg swing has a different timing than the more conventional single leg swing, but total swing energy does not seem to differ between the two styles.

Lavillenie has an excellent elastic to hollow swing position, effectively increasing the range of motion of the CoM relatively to the handgrip, keeping the pole away from him, making the swing dynamic and powerful. I think this is what he does exceptionally well.

It seems it was a surprise to many to learn that he aims for a free takeoff, since he so rarely achieves it - I believe that is mostly due to his pole carry the instant he initiates his plant. He starts his plant with his hands very low, and this affects his run rhthym during the plant. This is where I think he can improve.

But I would say the most significant factor that I attribute his world record to is that fact that Bubka never really reached his potential. Had Bubka been forced to compete, Lavillenie might be a less interesting discussion.


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