GRV: Lavillenie - From Stall Swing to World Record

[PVDaddy]

Kirk:

but I hadn't noticed how early he tucked. I'll look for that.

While your looking at that. I suggest you take a good hard look at just how much faster his pole is rotating then Bubka'a Pal! Or for that matter anyones! Take a good look! Does his feet come to the pole or is it the pole coming to his feet? https://www.youtube.com/watch?v=KrQWsMa ... e=youtu.be

Also you just may notice (If you actually look!) that the pole has it fastest rate of rotation toward the end of his tuck!

[PVDaddy]

Hey Will, this is off the subject but, but maybe my last for a bit as I have run out of points. I never got the chance to tell you yet that my Comment "Diss" was short for Dismiss. LOL and I was showing, feeling A little extra and probably sic sarcastic humor at the time! LOL Self humor can get the best of me at times! LOL Thanks for giving me the benefit of the doubt Good sense of humor is a great trait to have! Thank you for all the great thoughts and keep your minds open. Carry on fellows.

[willrieffer]

Will: Thanks, that's a good explanation. I know that he tucks "better" or "more completely" than any other tuckers, but I hadn't noticed how early he tucked. I'll look for that.

There is something here that I'm not sure if you are aware of or not and it's what I have termed "swing progressed". I will try and explain in the context of looking at RL and other tuck vaulters.

Since RL is doing all of these things to slow his post take off swing, he's going to be "behind" where other vaulters are in time to the swing. If vaulter A is at .2 seconds at angle A say at 20 degrees(and I'm just making these values up as example) to the vertical then RL at .2 second might be at only 15 degrees to the vertical. And then it might well be that vaulter A and RL both start their tuck at .7 seconds, but RL will still be behind vaulter A in swing angle progression even though the time is the same.

At the limit of possible swing progression in time, the vault will stall as the pole doesn't meet the necessary bend requirement for a lack of gravity compressive force, chord shortening, and then rotation velocity. This happens all the time with newer vaulters as they work back in forth between staying behind the pole and also being able to cover. And its a big part of what started me on this analysis.

Will

[willrieffer]

Kirk:

but I hadn't noticed how early he tucked. I'll look for that.

While your looking at that. I suggest you take a good hard look at just how much faster his pole is rotating then Bubka'a Pal! Or for that matter anyones! Take a good look! Does his feet come to the pole or is it the pole coming to his feet? https://www.youtube.com/watch?v=KrQWsMa ... e=youtu.be

Also you just may notice (If you actually look!) that the pole has it fastest rate of rotation toward the end of his tuck!

Joe,

It's not that the pole isn't "active" in the vault, it is in decompression, but other than that it is completely reactive. Or, its not moving to his feet. Optically, one might see that, but there is no physics to account for it as the CoM is the inertial point and also the thing from which the pole takes its horizontal velocity. What you are suggesting would only happen if again, something were accelerating the pole other than the vaulter say by a coach pushing the pole or some machine forcing rotation near the tip.

It's all good...


Will

[Wan]

I think you have now lot of materials to work on RL's technic (6.00+ 3 times now for this season...)
Just take a look at this on his last WL at 6.02m...
http://www.youtube.com/watch?v=eRYmGMvUwHo#t=3m35s
http://www.youtube.com/watch?v=eRYmGMvUwHo#t=4m35s
http://www.youtube.com/watch?v=eRYmGMvUwHo#t=4m52s
http://www.youtube.com/watch?v=eRYmGMvUwHo#t=5m12s
I'm impatient to read your comments and analysis.

For me, here is the most interesting post of this website... watching it daily... thanks guys to your will to drive it higher (even if it's not so easy...) !

[KirkB]

I think you have now lot of materials to work on RL's technic (6.00+ 3 times now for this season...)
Just take a look at this on his last WL at 6.02m...

Thanks for the vids, Wan. I love the pyrotechnics!

It's hard to criticize the WL and WR holder, but I notice how he toes his mark on the runway; leans back; but then LIFTS his toes off the mark and plants it a few centimeters/inches ahead of the mark as he starts his runup.

I'm sure he strives to be consistent in doing this, so that the distance he runs is precise on each attempt, but isn't there a chance of some randomness here? I mean, won't the amount that he steps forwards (past his mark) on his first (left) step vary a bit according to how (relatively) energetic he feels from jump to jump?

Wouldn't his runup be a more consistent distance if he removed this potential variance by not lifting his left foot off his mark?

To be more specific, do you think that a couple inches (or centimetres) variance in his takeoff point might be the difference between a make and a miss? And do you think that the way that he starts his runup might cause it to vary by a couple inches (or cms)?

Kirk

[willrieffer]

I think you have now lot of materials to work on RL's technic (6.00+ 3 times now for this season...)
Just take a look at this on his last WL at 6.02m...

Thanks for the vids, Wan. I love the pyrotechnics!

It's hard to criticize the WL and WR holder, but I notice how he toes his mark on the runway; leans back; but then LIFTS his toes off the mark and plants it a few centimeters/inches ahead of the mark as he starts his runup.

I'm sure he strives to be consistent in doing this, so that the distance he runs is precise on each attempt, but isn't there a chance of some randomness here? I mean, won't the amount that he steps forwards (past his mark) on his first (left) step vary a bit according to how (relatively) energetic he feels from jump to jump?

Wouldn't his runup be a more consistent distance if he removed this potential variance by not lifting his left foot off his mark?

To be more specific, do you think that a couple inches (or centimetres) variance in his takeoff point might be the difference between a make and a miss? And do you think that the way that he starts his runup might cause it to vary by a couple inches (or cms)?

Kirk

Kirk,

This is in part why Dossevi is important. Not because he is pushing the limit of efficiency in tech, but what might be accomplished simply by forcing the CoM back in time.

As I've pointed out at various times, this method is better oriented to produce results over normal take off variance. When a free swinger or non GRV vaulter comes up under and does not look to press the left or work to keep the CoM back, they take off in what again I call the "swing progressed" state. They are forward of the ideal swing angle in time. They lose the maximum of gravity compression from the start of the post take off phase, the compression rate is lowered, the pole doesn't bend enough or fast enough, the chord isn't shortened enough, and the vault fails.

This is not to say that I don't agree with your observation about his approach and take off, certainly in regards to the idea that he's into the free take off idea now. Like I have continued to try and point out, as the PB model was interested in eliminating having the hips thrown forward under pole braking, there is a commonality. It's just that as of now, with RL, and possibly with some other vaulters (In particular I like Lazero Borges trail leg work and press), that idea is being pressed to its limit in a more active way.

Will

Check this vid at about 12 sec. Take off leg back. Lead leg dropped where foot is below trail leg. His take off is double straight arm press and repress. I've also remarked on his spicy latin approach!

https://www.youtube.com/watch?v=P1oGwMXGYVI

[PVDaddy]

When Lavillenie lifts his drive knee into take-off, his knee is pointed down more than Bubka's and his drive knee heel is raised to the horizontal and comes very close to striking him (If it does not?)in the buttocks. His COG is further lowered as he lower's his drive knee foot.

Both of His feet are pretty close together by the time he reaches the sweetest spot of the swing, the active-I (both of his heals are pointing at the pit). Lavellenie pulls hard (Or leans very hard, depending on how you want to put it?) on his top hand, from the active-I, and maintains that pull and lean,while at the same time rolls the pelvis and knees up very quickly, through the very active bending of his spine,into a ball, with both knee tucked as tight as possible to his side. In other words, he pulls himself into a ball.

He is leaning on his top hand as hard as possible and the pole reaches maximum bend and accelerates and has now reached maximum rotational velocity. Lavellenie just takes the very fast rotating pole for a top hand leaned ride, and allows, and I believe even assist with his arms a very fast rotation of the pole to his feet.

His take off Knee is tucked very tightly and rolled all the way to his chest, between both his arms. into a very tightly packed all. This allow for a very active and powerful extension with both legs that add energy to is swing I call a tap at the top of his swing.

I believe both of those bolded points, are the answer to the riddle.

[willrieffer]

When Lavillenie lifts his drive knee into take-off, his knee is pointed down more than Bubka's and his drive knee heel is raised to the horizontal and comes very close to striking him (If it does not?)in the buttocks. His COG is further lowered as he lower's his drive knee foot.

Both of His feet are pretty close together by the time he reaches the sweetest spot of the swing, the active-I (both of his heals are pointing at the pit). Lavellenie pulls hard (Or leans very hard, depending on how you want to put it?) on his top hand, from the active-I, and maintains that pull and lean,while at the same time rolls the pelvis and knees up very quickly, through the very active bending of his spine,into a ball, with both knee tucked as tight as possible to his side. In other words, he pulls himself into a ball.

He is leaning on his top hand as hard as possible and the pole reaches maximum bend and accelerates and has now reached maximum rotational velocity. Lavellenie just takes the very fast rotating pole for a top hand leaned ride, and allows, and I believe even assist with his arms a very fast rotation of the pole to his feet.

His take off Knee is tucked very tightly and rolled all the way to his chest, between both his arms. into a very tightly packed all. This allow for a very active and powerful extension with both legs that add energy to is swing I call a tap at the top of his swing.

I believe both of those bolded points, are the answer to the riddle.

When he rolls up into the ball it moves his CoM back toward being underneath his top hand. And so he's once again moved the CoM to be more in line with gravity and the top hand and in doing so moved the CoM back. And for every action there is an equal and opposite reaction. IF he moves the CoM back by force on the pole, you have an effect, a force on the pole.

One of the things about the straight leg approach, at least as far as I can guess as no one apparently wants to explain it here, is that they believe there is a "see saw" type of force acting on the pole in decompression. In thought this is not completely wrong nor right, there are merits and flaws as I see it. If you are swinging the legs out and up one would think there would be a counter force on the pole, as for every action again a reaction. RL is doing an action/reaction activity on the pole as well. But since we don't know exactly what these forces are in magnitude, we can't quite compare them. Here we're back at a very complicated discrete type of analysis that isn't being done. So you have guessing and conjecture as theory. But I can say is that long swing lever out away from the pole in time is being countered by gravity slowing the swing, which is where much of the force and effort goes. This is counter to what RL does in that he keeps making adjustments to keep the CoM under the top hand as much as possible to keep gravity acting on the pole and not the swing as much as possible. Again, the farther a pendulum swings "up" and the further its mass moves away from the perpendicular, the less the mass acts on the pivot point by means of gravity. While you can and do get some things like a centripetal acceleration on the pole by the top hand through the swing and an action reaction counter force on the pole by swing activity, I've seen no science, physics, or mathematical proof exhibiting the magnitude of those ideas set against mine. Which is again to say, the PB or then straight legged swing form in some small ways seems like a good idea, but as far as I know, there's been no complete physical analysis done and no comparison proof. I take this since I seem to be the only one anyone has run into that thought to ask these questions.

And again, remember RL is being active as well and applying force on the pole too. It's different and new and a paradigm shift. He keeps using the action/reaction relation to keep moving the CoM back and apply force to the pole as well as working to maximize the gravity relation.

At some point maybe PVStudent will take a look at the CoM relation at about the time Bubka or RL are in the swing where their backs are more or less parallel to the runway. Or, maybe I'll get around to it.

Or lets try this...



The swing angle is shown at the top as Theta. Fg is the Force of gravity. As the swing angle increases, as theta increases, you have a relationship of the force of gravity on decelerating the swing, which is shown as FgSinTheta, and then gravity working on the pole through the vaulter to the top hand, which is FgCosTheta. As the pendulum or vaulter swings forward, FgSinTheta grows (again this is the decelerating force of gravity on the CoM during the swing progression) and FgCosTheta (the gravity force on the pole) shrinks. When Theta reaches 90 degrees the force of FgSinTheta = The force of gravity, which is now only slowing the swing and not acting on the pole, and FgCosTheta = Zero, which is the force available to act on the pole. And so now gravity is completely acting to slow the swing and not on pole compression.

That the force of gravity, Fg, is broken into constituent parts FgSinTheta and FgCosTheta is called vector analysis. That we can find these values at any particular time for a pendulum of this nature is for anyone versed in physics and math not too terribly difficult. To find them for the PV where the vaulter is constantly changing as one pendulum and then the other part is the pole that is both an inverted pendulum AND is a spring that shortens during compression makes the problem far more difficult. Really really difficult. It creates a complex curve for the CoM to follow and analyze and to do this discretely, at each step in time, which is what calculus does, makes it that much harder. You guys, most of you, have no idea how hard this is. I keep trying to show it and make it as simple as possible just to sort of get started. And yet its met with open ignorance by some and ignorant resistance by others...

Here's another illustration.



Here F(tens) is the force on the pole, and one can see its greatest at the perpendicular to the ground and grows smaller as the swing progresses. I hope maybe, maybe, this illustrates why it is good to keep trying to keep the CoM back and under the top hand by whatever means including lengthening the lever so it rotates slower, pushing the angle with the left hand, and even the movement where RL quickly balls up under the top hand and avoids being out away from the pole.

Will

[KirkB]

Good pics, Will! A pic is worth 1K words!

... Here F(tens) is the force on the pole ... RL quickly balls up under the top hand and avoids being out away from the pole.

If F(tens) represents tensile force, and F(grav) represents gravitational force, then these pics make a lot of sense.

In comparison to other elite tuckers, I note that RL does not pause nearly as much (if at all) as the rest of them. Instead, he's practicing the Theory of Continuous Motion!

For most Beginner and Intermediate tuckers, their downfall is that the reason they tuck is to PAUSE; to give the pole time to roll to vertical. RL doesn't have these passive inactions.

Kirk

[willrieffer]

Good pics, Will! A pic is worth 1K words!

... Here F(tens) is the force on the pole ... RL quickly balls up under the top hand and avoids being out away from the pole.

If F(tens) represents tensile force, and F(grav) represents gravitational force, then these pics make a lot of sense.

In comparison to other elite tuckers, I note that RL does not pause nearly as much (if at all) as the rest of them. Instead, he's practicing the Theory of Continuous Motion!

For most Beginner and Intermediate tuckers, their downfall is that the reason they tuck is to PAUSE; to give the pole time to roll to vertical. RL doesn't have these passive inactions.

Kirk

Interesting comments.

As I have said, his tuck is just different as well. I see most "tuck" vaulters progressing farther in the swing before really tucking, which goes against what I've presented here. They allow the CoM to go "out" to far in the swing/pendulum before trying to get back. They speed the rotation, but lost the gravity effect on the pole and may lose continuity as well.

If you have links or names of some tuck vaulters you're thinking of, I'll check them out.

Will

[grandevaulter]

https://www.youtube.com/watch?v=DxrlcLktcxU The real Strawman

https://www.facebook.com/video.php?v=10 ... =2&theater RL left handed

I contend that the result of RL's success is more of a result of his imagination and how he blends athletic ability and art. You will never put a finger on it with all of your "cut and paste" attempts at science.