GRV: Lavillenie - From Stall Swing to World Record

[PVstudent]

I love frames #5 and #6 (shown in PVStudent's posts above) of Lavillenie's 6.01m vault!

This "C" position is why he's the WR now!

Say what you will about his technique after the C (with distinct differences from SB), but if you can't get to the C (as he has), then if you want to vault high, it doesn't matter what you do in subsequent parts of the vault. He makes it or breaks it by his speed down the runway, to the point of the C. His bottom arm is so high above his head at this point that any perceived or real "push" on the pole is quite immaterial.

It's all about getting to this C, then whipping out of it! And the "whipping out of it" is the continuous pull (from take-off to lift-off) that PVStudent mentioned (and I commented on) yesterday.

And say what you will about RL's technique vs. SB's, this "C" (and all the good body posture that goes along with it) is what they both have in common!

Whilst I agree with most of the above I do not accept "This "C" position is why he's the WR now!"

The take-off of both vaulters is indeed very similar.

Their "C - Position" is somewhat similar but the differences in the consequences of their movement into the "C" emphasizes that the links in the kinetic chain prior to and post the instant of take -off must be assessed in the causal chain.

How the "C" dynamics work as a link in the continuous chain of motion suggest, even when this is a very strong link, it is the Weakest Link in the "Whole Chain" that will be the key determinant of success or failure in any vault!

Renaud Lavillenie pole support action sequence for 6.01m vault 2014 2.jpg (73.58 KiB) Viewed 10285 times

The drawing sequence above shows the pole support phases from take-off to final pole release.

http://youtu.be/ehtzp3OL0kg

The still frame images in Renaud Lavillenie's phase 1 of pole support taken from the exemplar video, shows in detail his movement through the "C position" into the positional configuration of his body at maximum moment of inertia about the top hand axis.

Renaud Lavillenie pole support phase 1 take-off to maximum moment of inertia about top grip 1.jpg (96.51 KiB) Viewed 10285 times

Renaud Lavillenie pole support phase 1 take-off to maximum moment of inertia about top grip 2.jpg (91.9 KiB) Viewed 10285 times

The video below shows that following take-off Bubka and Lavillenie do differ in their transfer of momentum technique in passing into and out of the "C" position, initiating their "Whip Swing" and swing follow through and in initiating inversion prior to pole recoil.

http://youtu.be/zqseTThPL5M

The "C - position" is a useful visual cue to the coach to indicate that the take-off has been effective. During the early part of phase 1 of pole support, observation of the "C" position should also assess the forward progression (run = horizontal penetration) is being maintained and that the pole bend is primarily forwards in the Sagittal Plane.

Any observation of the Vaulter and hand grips "sinking" ,at the end point in achieving the "C position" and as the leg swing initiates, is an indicator that the angular speed of pole chord rotation about the pole tip has been slowed using vaulter weight to increase pole bend. The consequences of this is increased potential for pole stall and or peak projection height being achieved well before the plane of the cross-bar is reached following pole release.

The next post will show how Lavillenie uses an entirely different inversion technique compared to Bubka.

[KirkB]

PVStudent, while at first glance I think any differences of opinion may just be due to you looking at this in more detail than myself (certainly more scientifically), I will have more to say once I read this more carefully, and contemplate this a bit.

However, I'm going on a road trip for the next few days, so won't have a chance to respond adequately until mid next week. Stay tuned.

I love this topic! Keep up the good work!

Kirk

[willrieffer]

Wow. Again a great divergence from the point. At least PVStudent admits that a discrete analysis is impossible and what we have is analogous to again a linear approximation. It's not wrong, but it is incomplete. I believe all of the physics presented concerning the advantages of the PB takeoff, but that is not the whole story, one that we can't get on CoM change in relation to pole compression velocity due to the CoM angles relative to gravity over time. Again, lots of smoke, no new fire....

I contend that Lavillenie presses the hips back and, against most other vaulters, transposes the legs, at least initially post take off. Where many vaulters will almost immediately tip the hips toward the swing, he tips his counter longer and more radically than almost any other vaulter. This necessarily moves his CoG down and back. What does this do? Over time it increases the rate of pole compression due to the relation to the gravity vector, shortening the pole faster and to more effect during compression, thus inducing it to a faster rotation. It also slows his swing speed rate during the action, which also keeps him back in time during the early pole compression, again to a positive effect on the pole.

Again, the PB Model eschews and gravity vector effect on pole compression analysis. They cared about keeping the hips back, contrary to a more American school, and it produced the same results I am talking about. It was an advance. They just did not take it to the logical extreme that Lavillenie has. Apparently, conditioning has prevented them from wrapping their head around the idea at all. Because, yes, you can free take off and work the GRV. In some ways, its the same thing, but with the considerations I outline missing.

Dossevi shortened the chord before ever taking off, using the take off leg to drive energy into the pole hastening its bend and thus "cheating" by basically taking off with a horter pole loaded with energy. Few have ever been able to do this. He got away with it because he locked the left and kept the shoulders and hips back. These were the advantages that offset all of the problems of his anti-PB model take off. At take off he started with a shorter pole loaded with energy. Lavillenie has put the two ideas together in practice with a free take off and press of the hips back, so he gets the best of both worlds.

The ideal of the model is also put to question when the ideal of the model is terribly hard to enact for even the best vaulters, by Bubka's own admission. You can't hit your take off mark every time. I contend that a GRV approach will lessen the detriments of take off variance in competition. Vaulters who actively stay back, and work to deform the pole over giving up posture will enact more good and safe vaults. Vaulters who are not "active" in keeping the hips back at take off and early pole compression , ones who simply allow their hips to be thrown forward on an under take off, lose the gravity compression element on the pole, have it not compress fast enough or far enough, and thus fail often dagerously. The gravity compression IS the "pull"! This is the point! Full extension of the arms keeps the hips back and make the longest lever! No coach would ever actually tell a vaulter to start pulling during compression! Lavillenie doesn't so much swing and "hang", then shortens the lever radically, and rolls up to the invert...

Will

P.S. Left Arm: The vaulter takes off and straightens the left arm. What happens? As they are hanging from a free pivot in the back hand, it pushes the shoulders back from the pole, followed by the torso, followed by the hips, pushing the vaulters whole CoM back, which is better. Since there is nothing but the vaulters weight as a counter force, almost nothing happens to the pole. As soon as this position is reached they are "hanging" in position where gravity pulls down on the pole.

[willrieffer]

Tucking from a long and powerful swing does not rob the vault of energy. TIM IS THAT A FACT OR AN OPINION? WOULD LIKE TO SEE THIS CLARIFIED IN TERMS OF THE BIOMECHANICS The law of conservation of angular momentum still applies. Gong from long to short speeds up the rotation but does not diminish the power of the swing. IS THAT A FACT OR AN OPINION - JUST THOUGHT THAT MAY OR MAY NOT BE RELEVANT - I KNOW ENOUGH ABOUT HAMMER THROWING TO KNOW THAT A HAMMER THROWER WOULD NEVER ATTEMPT TO SPEED UP THE ROTATION BY SHORTENING THE RADIUS OF THE SWING. What it does do is allow the athlete to stay low and behind the pole longer. HOW DOES SPEEDING UP THE ROTATION ALLOW THEM TO STAY LOW AND BEHIND THE POLE LONGER - I UNDERSTAND THE LOGIC THAT IF YOU KNOW YOU CAN GET UP SIDE DOWN FASTER YOU CAN AFFORD TO STAY DOWN LONGER - BUT IF THIS IS NOT CLARIFIED IN VERY SIMPLE TERMS IT WILL CERTAINLY BE MISUNDERSTOOD BY MANY COACHES - AND ALONG WITH THIS STATEMENT = A lower center of gravity in the first part of the jump is never a bad thing. MAY TAKE US BACK TO THE BAD OLD DAYS WHERE THE AIM WAS TO BEND THE POLE AS MUCH AS POSSIBLE BEFORE LEAVING THE GROUND - SOMETHING LAVELLENIE DOES NOT DO - AND TO TAKE OFF UNDER - AGAIN SOMETHING THAT HE DOES NOT DO.

However what really bothers me is the question of how you teach vaulters to jump like this in safety? With the Petrov Bybka model it is easy to take an absolute beginner forward in safety with a technical model that will be valid from their first take off until they break the world record. As I am primarily just a teacher, for me that is the critical question that trumps all of the above debate.

An case anyone was still aboard...

The above shows that Altius does or did not understand the basic physics concept of the conservation of energy in particular in regards to rotating bodies. And yet he wrote a book that uses physics to explain the event. And he was critical of any physics based critique of the event. This was the problem I first put forth long long ago. It wasn't that he couldn't coach the event, the results there do speak for themselves, and in that, his success as a coach, the book probably has great merit. You don't have to have a great deal of knowledge about physics to coach the event, but knowing some might help. But it was more particular that from these people you have to take the physics based explanations with a great grain of salt. And so while he tried to set up an equivocation about our relative coaching abilities, my criticism was never based on results, but specifically for the explanations for those results. So you might get a case where the methodology worked, but for reasons other than the ones stated. Or that the stresses on the particulars might be out of sync with the physics explanation.

And so while it was claimed I was trying to re-invent the coaching methodology (which I always denied), what I was trying to do was use the physics I know to get to a bit of a different and new way of looking at the event against older ideas formed by people that didn't know a lot about physics. In fact, if you look outside the physics, it wasn't even a particularly new idea. As I have repeatedly said, the PB was worried about the hips being thrown forward under pole braking. THIS was the important part of their transformation, based on physics, one that I think, trumped all the other things such as the overstressed idealism of take off methodology. Their well touted take off idealism fails under normal take off variance, which Bubka admits to, but it did keep the hips back! In what are probably two of Bubka's biggest jumps off all time, at '93 worlds, he leaves the ground with pole bend and it doesn't appear to hurt his height any! But he keeps the hips back, I'm sure. As well as he could have? Maybe, maybe not. But Lavillenie? I don't know that you could do it better. The left arm is extended, which by simple geometry makes the distance from the left hand to left shoulder longer, which presses the shoulder back in the swing in time, which moves the COM back, which effects the gravity vector on the pole chord shortening moment. This simplifies things actually. It pushes posture over placement in take off. Against take off variance, deform the pole and resist leaning back, not ideal, but safer and more effective. Placement, still must be a goal, but at some point you wind up working against yourself (for anyone that understands statistical management methods). It says that for those that can accomplish it, the longest slowest swing during pole compression is the best, and that necessarily the tuck will be necessary to get out. That is by the laws of conservation of rotating bodies. But that methods pushes difficulty. Any good coach can look at Bubka vs Lavillenie and understand the formers tech is easier to teach and get to results. Is it absolutely ultimately better in terms of physics (considering they both use the same plant tech approach)? I doubt it. I don't think so, and I've tried to explain why. The rest is up to you coaches. The longer you can get them to press and stay back, the better it is for the system, but can they get out in time and cover the pole?

good luck
Will

[grandevaulter]

The above shows that Altius does or did not understand the basic physics concept of the conservation of energy in particular in regards to rotating bodies.

Altius said that everything he knows he learned from other people and working with athletes. Petrov, Botcharnicov and Parnov to name a few. They probably don't know anything Will.

So you might get a case where the methodology worked, but for reasons other than the ones stated. Or that the stresses on the particulars might be out of sync with the physics explanation.

That is brilliant. must be "Luck over Science"

That is by the laws of conservation of rotating bodies.

I'll be sure to buy the next edition of that publication. Thanks for the heads up and keep up the great work.

[KirkB]

Grandevaulter, while I personally don't care to debate (or agree 100% with) Willrieffer's post, he does attempt to use SCIENTIFIC REASONING for his assertions. Therefore, in the spirit of the true purpose of this PVP forum - which I believe is to discuss and share knowledge for the common good of all vaulters and coaches, I think he deserves better than a sarcastic reply.

Altius is no longer with us to defend himself or his interpretation of the scientific and practical methods that he learned from others and by his own personal coaching EXPERIENCE (may he rest in peace), but I think we should all strive to carry on the scientific basis (including experimenting with various training methods, throwing out what doesn't work, and continuing to use what works) that he has established. I think this is what I think Willreiffer is trying to do, so kudos to him for that (even though he may seem like a thorn in your side).

I suggest that we focus on the merits of the physics behind PV technique of Bubka and Lavillenie, and how that science can be applied to improving the technique and training methods for all of us.

In this particular thread - comparing Bubka an Lavillenie's techniques - I think we've already learned quite a bit (thanks to Willrieffer, PVStudent, and others), and I hope we can keep this discussion going.

You might think that science is science, and there's only one right answer to each scientific question. But the thing is, people interpret science differently, and emphasize different aspects of scientific principles, depending on their own biases, knowledge and life experiences.

I will be the first to admit that I was surprised by Lavillenie's WR with a technique that I have - up until this year - ignored or discarded as sub-optimal. But I still don't even understand what his INTENT is in each part of his vault, so that I can use this as a basis for changing my own thoughts about how to modify my training/coaching approach.

I would like to keep my mind open for comments from all sides, at least until I can understand this better.

Kirk

[grandevaulter]

The above shows that Altius does or did not understand the basic physics concept of the conservation of energy in particular in regards to rotating bodies.

Altius coached NCAA champions in the shot put, discus and long jump when he was at Western Kentucky. Luck or Science? Will's opening statement is a cheap shot. Will you have no class.

And yet he wrote a book that uses physics to explain the event.

I seriously doubt that you have read the book or you wouldn't make a bogus statement like that.

And so while it was claimed I was trying to re-invent the coaching methodology (which I always denied), what I was trying to do was use the physics I know to get to a bit of a different and new way of looking at the event against older ideas formed by people that didn't know a lot about physics

Keep trying on using physics and which people are you talking about, Petrov ?

conservation of rotating bodies

Is this a scientific term?

[KirkB]

conservation of rotating bodies

Is this a scientific term?

This phrase threw me at first too. Will's choice of words may not be very scientifically precise here, but I knew what he was referring to. A better choice of words might be "angular momentum", or "rotational momentum" or "the conservation of energy of a rotational body".

I hope we can get to the REAL issues, rather than nit-picking about unscientific wording.

Kirk

[KirkB]

So you might get a case where the methodology worked, but for reasons other than the ones stated. Or that the stresses on the particulars might be out of sync with the physics explanation.

That is brilliant. must be "Luck over Science"

In a round-about way, this statement by Will does make some sense.

When a vaulter executes a vault, he usually does so with some cognizant INTENT to use the Laws of Physics to his advantage. But sometimes, HAPPENSTANCE happens, and sometimes INTUITION happens. In either case, the vaulter (and/or his coach) may not fully understand why something that they just did worked well, but it still follows the Laws of Physics EXACTLY. This has personally happened to me on a few occasions.

Happenstance is basically a coincidence that (in the context of this discussion) just happens to be a combination of GOOD things that happened during a vault.

And intuition is basically a good combination of things that happened not because the vaulter intentionally did them on THAT particular vault, but because his training regimen caused his muscle memory to react in a rather automatic way. A couple good examples of this are the way Kjell Isaakson was so vague about how he swung ("I just jumped"), and the way Bubka described the details of how he swung ("Arrrrgh"). This is the reason that I encourage highbar work so much.

I don't mean to be defending Will too much here, as I probably disagree with more than half his "scientific" assertions. However, his alternate, minority view has opened my eyes wider than they were open before.

Kirk

[grandevaulter]

Kirk, I appreciate your open mindedness. You are fair and give everyone a chance. You are a good man.

[willrieffer]

Yes, conservation of energy is a physics property that pertains to all moving bodies. So it is the conservation of energy in the rotation. Its the same idea that kills the "box energy loss" idea as the box doesn't move appreciably during the vault. This is actually made very clear. It's not really up for debate or conjecture. And it remains that altius had to ask whether it was "fact" or "opinion". He didn't know...

I know all kinds of good coaches that don't know anything at all about physics. You don't have to know it. But knowing it might make you better, or at least being open minded toward someone that does know it might help. The argument that you try to set up grandvaulter is so many straw men. Altius, I have agreed, had a talent for coaching. It wasn't luck. It was skill. That still doesn't mean he knew very much if anything about physics.

What I am talking about is the manipulation of the swing angle in time and its effect on then the COM and then further the COMs effect on the pole compression phase. That is the closer to the perpendicular that the COM remains the more force gravity exerts on pole compression, thus shortening the chord in time. And a shorter chord rotates faster, and this further. So it benefits the vaulter to be a long as possible and press the COM as far down and back as possible. This is all of the things Lavillenie does with the left arm, dropping the lead leg, working the take off leg back. That trade off is in getting out, for which he changes his rotational speed by then rapidly shortening the lever by his aggressive tuck.

The PB generation model did not look at this. The didn't look at the pole at all sans take off, which is why I think this is all very hard for them to understand. Pole mechanics are difficult. Take off angles are easy in comparison.

I get it. There a lot of emotions involved in this, at least on one side. Much of all that is unfortunate.

But the facts remain. I'm not making anything up here. I don't have that agenda.

I think science can help people understand the event. That is all. I've presented the case. And I've made a case as to why the PB model is both still worthwhile, and why it has some shortcomings, and how there is new information to go with Lavillenie's presence, to put forth there is a needed addendum to the approach.

Thanks for taking up the case, Kirk.
Will

[willrieffer]

You might think that science is science, and there's only one right answer to each scientific question. But the thing is, people interpret science differently, and emphasize different aspects of scientific principles, depending on their own biases, knowledge and life experiences.

Kirk

In some sense you leave the door open for people to, I don't know, argue the well established laws of physics.

From NASA...

The conservation of momentum is a fundamental concept of physics along with the conservation of energy and the conservation of mass. Momentum is defined to be the mass of an object multiplied by the velocity of the object. The conservation of momentum states that, within some problem domain, the amount of momentum remains constant; momentum is neither created nor destroyed, but only changed through the action of forces as described by Newton's laws of motion. Dealing with momentum is more difficult than dealing with mass and energy because momentum is a vector quantity having both a magnitude and a direction. Momentum is conserved in all three physical directions at the same time.

In the end, you cannot argue against this and that the event has to hold to the laws.

Now, it is complicated. And so you can see that say in the case of PVStudent, I do not say he is wrong, only that his view is incomplete. I've made this case before. That the PB model is analogous to a linear approximation, one that concentrates on certain aspects of the vault, notably take off, and worries less if at all about some other aspects, namely what I am interested in the compressive force of gravity post take off on the pole compression phase relative to the vaulters swing angle in time.

In the current era of dynamic system studies there is allowance that some systems have multiple equilibrium states, and this, I think, pertains to the vault. Sometimes "style" comes up. Well, physics has no regard for "style" there is only the laws. There is only style if two vaulters can generate the same COM path but use differing body placement. This is possible.

So while some of these things are open to argument and interpretation, or "style", other parts of it are not. Not at all. There is no argument about the conservation of momentum. It just is.

And its why Lavillenie vaults the way he does. He lengthens himself and pushes the COM as far down and back as possible. This slows his post take off rotation during pole compression. He maintains a better relation to gravity. And to get out he has to shorten the lever, that is tuck, which then speeds his rotation due to conservation of energy. There is no argument that this IS happening. It is visible, and it coincides with the laws of motion.

Will