GRV: Lavillenie - From Stall Swing to World Record

[willrieffer]

Joe,

"Centrifugal" is, where physics is concerned, not real and thus where the pole vault is concerned an almost meaningless term. The pole supports the vaulter in the air. That is all. You need to let go of that term and idea where the poles rotation is concerned. And so, you used it again, and that makes it hard for me to provide any sort of answer to your question.

Further I have only a scant idea what you are talking about in terms of "fighting the pole". I'll get back to this...

http://en.wikipedia.org/wiki/Dynamical_systems_theory

There is a lot of deep science in the above. And its just the beginning. I don't know what you'll be able to make out of it.

What the above basically says in terms of the pole vault is that there are different ways to get to a necessary state to complete the vault. It would be easiest to say that point is the relations at max bend, but again, that would be a simplification. In the past I have postulated that there is perhaps a high path and also a low path that yield almost similar results. And in this case the PB Model and so Bubka represents the high path. And Lavillenie and the likes of Joe Dial would represent the low path. It is to note that we see here a tall and short divide, and PVStudent has discussed this elsewhere. Because short vaulters start at an angular take off disadvantage they have to find more rotation. Also, since they are shorter, their natural tendency in the swing will be to rotate faster, which as I have outlined, is a problem. So you see these shorter guys with more active left arms. They have to do it to keep back in time and more in line with the gravity vector.

Because pole dynamics are hard, very very hard, the PB Model basically said, "we're not going to worry about it". And they maximized the easy part. The freeze frame view of the take off. They were very successful with it. But as I have said, its analogous to what is called a linear approximation in mathematics. It leaves stuff out. The pole. It leaves that as the art of picking a pole. And they drive high, jump high, onto the pole. It has advantages. More advantages if you are taller. It is here where I have to say, I cannot wrap my head around the idea that Bubka in any way "fights" the pole. It goes against my own critique of his vault, which is that his high rotational speed was a product of his high runway speed combined with using poles that were shorter and stiffer than ideal. His vaulting was easy. And it looks easy. Lavillenie has to work harder. That has been part of the point of all of this.

The other things, which amount to analyzing the posterior view for angles and forces in time would be incredibly difficult as well.

This is to say, I can't seem to find the same outlook on these things at the moment. And even if I could, I don't know that I could do any good with the analysis and so provide any help or backing toward your thoughts. We're having enough trouble with the side view here.

Again, even though the pole is rotating, there is no "centrifugal" force in physics, or the event. There is a small amount of centripetal acceleration associated with the vaulter rotation about the top hand, but that's about it.

Will

[PVDaddy]

Will, if you don't want to use the damn term "Centrifugal" to describe that force that the bending, but more specifically rotating pole applies to the vaulter and its impact on his swing depending with how the vaulter utilizes it than call it what ever you damn well like use it in place of it and go back and take a serious read of my post. I have asked you and you still have not supplied what would be a more appropriate term. Forget the term use another and go back and reread my thread and click through the various side by side comparison of Lavellinie's swing and Bubkas as you read it. Make a physical examination. HIS POLE ROTATION IS SICK! It holds great merit and you do not strike me as a political personality but like me one most interested in learning and exploring the very best physics of the vault. Being an all State Wrestler certainly you understand the ver fine For me this is the most fun part of learning about anything that interest me. I have tried to keep it simple but I feel like you have closed your mind to thinking about what I have said simply because you don't like the term I used to express it?

[PVDaddy]

How is it possible he could swing so low what appears an almost delayed low glide and yet still cover that pole with ease and in plenty time? I have full describes how I feel he accomplishes that by taking full advantage of the gravity vector and of equal importance by taking making much better use of a rotating pole. Nice to chime in.

[willrieffer]

Will, if you don't want to use the damn term "Centrifugal" to describe that force that the bending, but more specifically rotating pole applies to the vaulter and its impact on his swing depending with how the vaulter utilizes it than call it what ever you damn well like use it in place of it and go back and take a serious read of my post. I have asked you and you still have not supplied what would be a more appropriate term. Forget the term use another and go back and reread my thread and click through the various side by side comparison of Lavellinie's swing and Bubkas as you read it. Make a physical examination. HIS POLE ROTATION IS SICK! It holds great merit and you do not strike me as a political personality but like me one most interested in learning and exploring the very best physics of the vault. Being an all State Wrestler certainly you understand the ver fine For me this is the most fun part of learning about anything that interest me. I have tried to keep it simple but I feel like you have closed your mind to thinking about what I have said simply because you don't like the term I used to express it?

Well...

When the vaulter takes off, sans his take off jump, the pole supports them as a spring. Because of the angles and energy, it pushes them up from take off through the vault. The pole/chord system rotates, but the energy all comes from the inertial state of the vaulter and their relation to gravity and is placed into the pole. The vaulter's energy as inertia drives the system in the horizontal, and again sans any jump at take off the pole supports the vaulter in the vertical. It is here I have to say, pole rotation doesn't energize the system or vaulter in any way. The only way that happens is in certain drills where someone, usually a coach, will grab the pole and drive the pole forward under the vaulter adding force to the rotation. Pole rotation is not a thing unto itself but is a reaction to the vaulters inertia, and then only a means to an end. Getting from the take off to the plane of the crossbar. More and faster bend means two things. More energy is going into the pole at a faster rate and since the chord must be shortening faster to do that it rotates faster toward the crossbar. All of that is good. It's what you are talking about. And with Lavillenie its what you and I are seeing. You're eyes aren't deceiving you. And the difference you see between the two are noticeable and what we've been talking about. And its what I've been trying to explain...

But...

Again, there is no replacement for "centrifugal". Its a word that stands for the relation of inertia to centripetal acceleration. It's not a real thing, but a word that represents the subjective feeling of experiencing inertia in a rotating system. As it is thus, there IS no word to replace it. I can't replace it. There is nothing there to replace.

Will

[willrieffer]

How is it possible he could swing so low what appears an almost delayed low glide and yet still cover that pole with ease and in plenty time? I have full describes how I feel he accomplishes that by taking full advantage of the gravity vector and of equal importance by taking making much better use of a rotating pole. Nice to chime in.

I have made mention of how his tuck is almost fundamentally different than anyone else. He takes off and basically holds himself back and hangs under the pole as it moves forward. At about the time it reaches max bend he initiates a very sudden ball/tuck. And then "rolls" up over the pole. That he reduces the rotational axis speeds up his rotation to get over the pole and also allows his muscular work to do so to be more efficient. He spends less time with his CoM out away from the pole in this transition phase and so it spends more time in line with the gravity vector. Its also less time that gravity is robbing energy from the swing.

How is his tuck different? He initiates it sooner than most and its more "violent". If you care, compare it to other tuck vaulters most of whom have what I call a vestigial tuck. They do it, but its so late as to be almost useless and unnecessary.

Will

[PVDaddy]

It is here I have to say, pole rotation doesn't energize the system or vaulter in any way.

Will are you also saying that the rotating pole has no impact on the direction of the swing and more specifically that the vaulter does not have the abillity to make adjustments on their swing that would result in greater swing efficiency if they timed it to the proper pole rotation. Another way of asking this is, Is it possible that the swing could take less energy if it was properly matched to the poles rotation point? Is it Possible that the point in time that lavellinie performs his major rotation (Which appears much earlier in the vault than Bubka's) is a more efficient time and requires less energy to make? Is not saved energy mean more energy to utilize in the rotation?

Again, there is no replacement for "centrifugal". Its a word that stands for the relation of inertia to centripetal acceleration. It's not a real thing, but a word that represents the subjective feeling of experiencing inertia in a rotating system. As it is thus, there IS no word to replace it. I can't replace it. There is nothing there to replace.

I am looking for the word that describes the impact that the leaning and bending but more specifically "rotating pole" places on the vaulters swing path and its resulting impact on the velocity of the vaulters swing. Evidently you do not believe it does and here is were we part ways. The position of the rotating pole at lavellinies major rotation to inversion is (When he goes upside down) is much different then the position of the rotating pole when Bubka inverts (going upside down)
I am also confident that the position of that rotating pole makes a difference to the way it deliver energy to lavellinie than it does to Bubka in flyaway.

More and faster bend means two things. More energy is going into the pole at a faster rate and since the chord must be shortening faster to do that it rotates faster toward the crossbar

He spends less time with his CoM out away from the pole in this transition phase and so it spends more time in line with the gravity vector. Its also less time that gravity is robbing energy from the swing.

How is his tuck different? He initiates it sooner than most and its more "violent". If you care, compare it to other tuck vaulters most of whom have what I call a vestigial tuck. They do it, but its so late as to be almost useless and unnecessary.

[willrieffer]

It is here I have to say, pole rotation doesn't energize the system or vaulter in any way.

Will are you also saying that the rotating pole has no impact on the direction of the swing and more specifically that the vaulter does not have the abillity to make adjustments on their swing that would result in greater swing efficiency if they timed it to the proper pole rotation. Another way of asking this is, Is it possible that the swing could take less energy if it was properly matched to the poles rotation point? Is it Possible that the point in time that lavellinie performs his major rotation (Which appears much earlier in the vault than Bubka's) is a more efficient time and requires less energy to make? Is not saved energy mean more energy to utilize in the rotation?

Well, for these questions, no and yes. The pole is important and how the vaulter uses it us important. The angles and relation to the gravity vector matter. And, as I've shown, the vaulter can do things to "steer" the system to better efficiency. That is the nature of the vault. So most of these things above I agree with...

Again, there is no replacement for "centrifugal". Its a word that stands for the relation of inertia to centripetal acceleration. It's not a real thing, but a word that represents the subjective feeling of experiencing inertia in a rotating system. As it is thus, there IS no word to replace it. I can't replace it. There is nothing there to replace.

I am looking for the word that describes the impact that the leaning and bending but more specifically "rotating pole" places on the vaulters swing path and its resulting impact on the velocity of the vaulters swing. Evidently you do not believe it does and here is were we part ways. The position of the rotating pole at lavellinies major rotation to inversion is (When he goes upside down) is much different then the position of the rotating pole when Bubka inverts (going upside down)
I am also confident that the position of that rotating pole makes a difference to the way it deliver energy to lavellinie than it does to Bubka in flyaway.

The pole rotates and its position in time is important. This IS what we have been talking about. I have stated that between these two the swing is different and that Lavillenie's swing is more efficient. Is it related to his relation to the pole in time? Yes, yes it is. As with previous dialog in this thread. We are seeing the same things, but it still seems you are driving to see something else that I can't quite see or I do see but just doesn't match with your dialog and terminology i.e. "centrifugal".

There are lots of ways the swing could bear out as inefficient. Too far left or right on take off is going to angle the system and pole and cause the vault to be less than ideally vertical. As I pointed out, its a complex dynamic system. There are a lot of things where one could become either more or less efficient.

More and faster bend means two things. More energy is going into the pole at a faster rate and since the chord must be shortening faster to do that it rotates faster toward the crossbar

He spends less time with his CoM out away from the pole in this transition phase and so it spends more time in line with the gravity vector. Its also less time that gravity is robbing energy from the swing.

How is his tuck different? He initiates it sooner than most and its more "violent". If you care, compare it to other tuck vaulters most of whom have what I call a vestigial tuck. They do it, but its so late as to be almost useless and unnecessary.

[PVDaddy]

The pole rotates and its position in time is important. This IS what we have been talking about. I have stated that between these two the swing is different and that Lavillenie's swing is more efficient. Is it related to his relation to the pole in time? Yes, yes it is.

Good, I'm glad you acknowledge that. and......
I am suggesting that "The amount of the Poles Rotation" and "Its position " is just as important as the" gravity vector" in producing a vault with Maximun Efficiency and I am suggesting You not Diss it off so lightly! It's Very, Very Significant in my opinion! Yes it has been mentioned to some extent as just a result of early pole compression, but, I am suggesting that it is much more important than Just a result of pole rotation. I am suggesting that Renauld lavillenie makes every effort (With every intention) to ensure the fastest and most complete rotation he can! I am suggesting he fully acknowledges the value of that rotation. I am also suggesting that its speed and Placement effects the efficiency of that swing at every stage of the vault. It's that significant!

or I do see but just doesn't match with your dialog and terminology i.e. "centrifugal".

Examine this clip and answer with just a simple yes or No to the following questions if you would please? I encourage you to stop the video throughout the various stages of the swing as well examining the pole's rotation of Renauld Lavillenie and Sergey Bubka clearing 6 Meters.

1) Do you agree that Lavillilenie's vault has more rotation then Bubkas? https://www.youtube.com/watch?v=KrQWsMa ... e=youtu.be

[PVDaddy]

Also Will while your reviewing that do you notice any of the following?

So what are some things that lavillinie does different than Bubka to effect (Increase) the rotation of the pole? As you stated his low COG at penetration results in a greater early pole bend, shortening the chord and thus greater rotation. But why is this so from a Physics standpoint? Is it because it provides Lavillenie with a longer lever (L-shape) and therefore greater leverage? I have noticed at plant Lavellinies take of angle is different and he appears to be taking of more from the right side and his drive knee is pointing more to the left and inducing more spin on the pole. Bubka appears to be attacking straight on. Also going into penetration his spine twist much more and this is evident by the left to right movement of his trail leg. At this point Lavellilenies bottom hand is already extended and Bubkas hand is above his head. I am suggesting that as Bubka performs the upward and forward extension of his bottom hand this limits the natural rotation of the pole. lavellinie just glides in his low Cog position which allows the pole to rotate freely and uninhibited. He is just allowing the GV and pole rotation to work its magic. Lavellinie's pole has already rotated a great deal at this point and Bubka's hasent even rotated at all. Both of Lavelinies feet are pointing straight down taking full advantage of his GV ride and Bubka's feet are spread way apart with his drive knee high. At this point Lavellinie loosens his thumb grip on the bottom hand and keeps all his weight on the top hand (The end of the lever) which provides more pole bend and allows the pole to rotate even more freely and Bubks has a tight grip on the pole. Lavellinies swing path is orientated much more severely to the left and in order to orientate it to the target he must pull down on the pole with his bottom hand and direct his swing to the right. Does that act speed pole rotation as well? As he swings he provides maximum lean on the top hand and the chord has reached it shortest length. His pole rotation has reached maximum velocity at this point and coincides perfectly with his double leg tuck which I believe also speeds rotation and at the same time he is able to capture the maximum force the pole has to offer to his swing through its rotation and at the perfect moment. This is why Lavillenie is able to cover the pole so quickly from what appears to be a relaxed delayed swing.

[willrieffer]

Well, I don't think I'm "dissing" you. I think I've been pretty clear and generally charitable in our dialog. We appear to have one problem, the use of "centrifugal". It's continuing problem because, and here I have to guess, you "see" something that you are, or have, labeled with it, and by physics I know its a phantom force. So your use of it prejudices me to seeing anything, or more specifically, what you are seeing.

What causes pole rotation, bend, and rotation speed. Think about it.

1) The primary energy of the vault is initially from the horizontal KE of the vaulter. Also, its relative to the take off drive and angle.
2)Pole compression is a combo that coming from the horizontal element of the take off vector plus the gravity compression. The more the pole compresses and the faster and shorter the chord gets, the more it rotates and moves to the clearance plane. Everything I've said on this topic is relative to maximizing as much as possible the gravity force to gain more compression, pole energy, and rotation, for all of those things are good.

When I look at the vid, I see more and faster compression with Lavillenie. And it looks like Dial who used a lot of bend. It will yield the results as stated and I have used physics to say why. His pole and CoM move differently in time based on his body positioning. So, to all you've said in general, "Yes". Still, there seems to be something you want me to say about other specifics. I don't know that I can.

Sartre advised that its imagination the finishes the world. And that its a problem. We all imagine things, and we believe in what we imagine.

Will

[PVDaddy]

I would also like to point out that Lavillinie has managed to cover the pole so quickly while performing his double leg tuck, (I believe that is because of his Low COG swing, the shortness in his tuck and the speed and position of the pole in its rotation at the time of his tuck.) that he has time to spare. The pole is out to his side at this point, It has rotated about 45 degrees. He makes no effort to extend is hips any further upward until the pole has rotated yet another 45 degrees and is now behind him. Why did he do that? Will the pole from this position apply the same forces and/or the same direction on Lavellinie that it applies to Bubka from his position and the position of his pole?

[PVDaddy]

The more the pole compresses and the faster and shorter the chord gets, the more it rotates and moves to the clearance plane

.

Why is that Will? Also,Is there anything a vaulter can do beside compression, that would effect the speed and or amount of that rotation?