Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

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Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby willrieffer » Sat May 17, 2014 5:19 pm

Because someone asked...

Common sense told me it took a certain amount of energy to lift Bubka 20 ft. I needed to determine what that was. I did. I knew a large percentage of that energy was generated in the Runway. I determined how much that was. I understand runway energy is stores in the Vaulter pole/system.I figured if I subtracted the energy generated in the runway from the energy required to raise Bubka 20 ft the remaining energy would be what Bubka produced from swinging, Pulling, Pushing Etc. after he left the ground. Make sense?


Yes, it is a good starting point. But the problem is that we are talking about a very complex system with an almost hidden amount of energy being controlled by gravity. As I said, the gravity component in the pole is regulated by the vaulters swing angle which is changing, which makes the system into one in which differential calculus is needed. This is why most people would want to avoid the problem if thinking about how gravity effects the vaulter + pole system.

But the totality of your thought and process is a correct starting point for determining efficiency.

Bubka 6.15m 80kg 9.94 m/s
Tradenkov 6.01m 78kg 9.47m/s
Lavillenie 6.16m 69kg 9.49 m/s

Lavillenie take off speed comes from here...
viewtopic.php?f=38&t=44165
The others come from the PVP 6m club chart.

PE = mgh
Bubka = 80kg x 9.8m/s/s x 6.15m = 4822j
Tradenkov = 78kg x g x 6.01m = 4594j
Lavillenie = 69kg x g x 6.16m = 4165j

KE = 1/2 m x v squared

Bubka = 1/2 x 80kg x 9.94 m/s x 9.94m/s = 3952j
Tradenkov = 1/2 x 78kg x 9.47m/s x 9.47m/s = 3498j
Lavillenie = 1/2 x 69kg x 9.49m/s x 9.49m/s = 3107j

Total take off to clearance gains...

Bubka 870j
Tradenkov 1096j
Lavillenie 1058j

Efficiency as PE/KE
Bubka = 4822j/3952j = 122%
Tradenkov = 4594j/ 3498j = 131%
Lavillenie = 4165j/3498j = 134%

Of course one can bring up clearance height. I can't do anything but with the numbers I'm given here. Also, this outcome is not so much an indictment of the PB model, as of Bubka's placement in it. I have contended that his speed actually allowed him to be less swing efficient, and this somewhat bears me out.

Hope that helps...
Will

P.S. I included Tradenkov as I continually find him fascinating as one of the slowest men to vault 6m and because I believe he had to diverge somewhat from elements of the PB model by regulation of his swing speed and use of tuck.
P.S.E. To get to 130% efficiency Bubka would have to clear 6.55m from a take off velocity of 9.94m/sec...

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby willrieffer » Sat May 17, 2014 11:38 pm

Will thank-You for doing the math and collecting the data as I asked and posting it here on PVP. However, I am afraid your process for determining efficiency was incorrect. It is impossible for a vaulter to be more than 100 % efficient. A vaulter is more efficient if they can add more Post take off energy relative to the total required clearance energy compared another vaulter. I believe the equation you should have used for each vaulter is PE-KE / PE. That would represent the percent of energy attributed to the vaulters post take off actions. I believe it would be: Bubka 18% , Tradenkov 24% and our hero Lavellenie 25%!
Do you agree? If so would you mind re-posting the correct calculations for us? I and I am sure others find this very useful and informative!


It is a matter for interpretation. As I illustrated the method, showed how the calculation was derived, it is saying the vaulters ended with a positive percentage of their take off energy. Or, you're method is equally valid and illuminating. In fact, both together are probably the best illustration.

Will

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby dj » Tue May 20, 2014 7:39 am

put this swing into the mix....

http://www.youtube.com/watch?v=uA7Dapjsh9A

dj

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby willrieffer » Tue May 20, 2014 8:40 am

dj wrote:put this swing into the mix....

http://www.youtube.com/watch?v=uA7Dapjsh9A

dj


Kinda doing something else I'm gonna post here in a moment, but good gracious he looks slow LOL. Nice vault however.

Do you have any idea of his weight and take off speed? Then I can do the math.

Will

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby willrieffer » Tue May 20, 2014 8:54 am

Will, if your data is correct then these results are very significant!


But the problem is that we are talking about a very complex system with an almost hidden amount of energy being controlled by gravity. As I said, the gravity component in the pole is regulated by the vaulters swing angle which is changing, which makes the system into one in which differential calculus is needed. This is why most people would want to avoid the problem if thinking about how gravity effects the vaulter + pole system.


The gravity component may be hidden to some extent ,but, regardless, it reveal itself in the amount of pole bend, the direction of pole bend, the timing of the pole bend and final bar clearance, which is what counts. Of course the purpose of this study was to determine swing efficiency. What percent was added bar clearance by post take-off actions. This was not hidden in our calculation of swing efficiency, it was included. Why do you think differential calculus is required here? Gravity is a constant. Its force on the vaulters mass remains the same whether the vaulter is vertical, horizontal or sideways. However it does effect the direction that force is applied to the pole. Is this what your saying here?



Also, this outcome is not so much an indictment of the PB model, as of Bubka's placement in it. I have contended that his speed actually allowed him to be less swing efficient, and this somewhat bears me out.


Why do you say that a fast swing speed would ever be detrimental to the vault? A fast downswing produces a faster upswing into fly.I have watched Lavellenies vault now a hundred times and I can seen no pause or delay? If anything, I think Bubkas swing takes more time. It would be valuable to have a swing time on both vaulters.


Gravities effect on the vaulter is constant, but in the system that force can be resolved into deceleration of the swing moment OR compressing the pole and the difference in how much each of those forces is is determined by the vaulters ever changing swing angle. That is why to analyze it you have to use differential calculus. When the vaulter is perpendicular to gravities effect, it resolves totally into pole compression (or in actuality against any upward thrust by the vaulter at take off) but as they swing forward it begins to decelerate swing speed and act less on the pole as it is a constant force. It is by this understanding and logic that you see that swing braking puts swing energy into the pole and also presents a better relation to gravity. It drives the pole more, compresses it more, and rotates it more.

As you point out, swing moment energy/swing speed adds little to the vault besides helping to get the vaulter in position, to the vertical, in time. The noted IAAF study presented a rather positive slant Bubka's swing speed noting it was higher and more constant than for any other vaulter studied, and also noted that all others saw mid swing swing deceleration.

I don't know or think you can just watch a vault and pick this effect out without special video equipment and software analysis. I get there by scientific knowledge and logical analysis. Lavillenie pole brakes and double leg swings which both swing brake his early vault. He of course then speeds his rotation to the top with a very fast tuck sequence.

Our swing efficiency numbers are very...loose. They do not take into account clearance height nor are they based on individual vault take off speed where we could find some variance. Or, I don't think Bubka is as inefficient as those numbers portray. His IAAF take off speed numbers go from around 9.5+ m/s to 9.8+ m/s possibly 9.9 m/s. This shows two things. That he was probably well capable of 9.95 m/s, and that he probably had an average of around 9.7 m/s +/- .2 m/s. Lavillenie has a reported average of just below 9.5 m/s, but what is his variance. Well, it could be +/- .2 or it could be something else. IF I look at the IAAF data, I tend to see that Bubka had slightly more variance than most other vaulters. This is all to say that I think Lavillenie is probably capable of a take off around 9.6 m/s to 9.7 m/s. And it is that we probably have to think that any vaulters greatest heights are going to be achieved at or near their max take off velocity for Bubka probably 9.9+ m/s and for Lavillenie probably in the range of from 9.6 m/s to 9.7 m/s. Now to clearance height. I think Lavillenie's WR was probably slightly over 6.2m possibly as high as 6.25. I also think Bubka was probably capable of something around 6.4m from video evidence. That would probably close the efficiency gap somewhat with Bubka getting additional height and thus more efficiency, but as I pointed out above, you have to set Bubka against 6.55m to get 130% efficiency from his reported max take off energy. And I don't think he was capable of 6.55m.

PE = mgh
Bubka = 80kg x 9.8 m/s/s x 6.4m = 5018j
Lavillenie = 69kg x 9.8 m/s x 6.2m = 4192j

KE = 1/2 m (v squared)
Bubka = 1/2 x 80kg x 9.9 m/s x 9.9 m/s = 3920j
Lavillenie = 1/2 x 69kg x 9.7m/s x 9.7 m/s = 3246j

Efficiency as PE/PK
Bubka = 5018j/3920j = 128%
Lavillenie = 4192j/3246j = 129%

I fudged things about as far as I felt comfortable in doing in Bubka's direction. And so we get a bit of a different conclusion. Based on the Tradenkov information we get more of an idea that both forms, either the PB model or the Lavillenie method are probably pushing max efficiency and its quite possible that the differences in swing style either cancel out or the variances are not significant.

Will

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby canag » Wed May 21, 2014 6:33 am

I usually don't post on threads about vaulting technique, as I am not a PV coach. But I know some physics (teaching at university) so I'll join this discussion!

Your approach seems interesting to compare different vaulters efficiency from objective statements. I have some comments about the model:

- "an almost hidden amount of energy being controlled by gravity" There is no "hidden" energy controlled by gravity, the only change in energy due to gravity is center-of-mass vertical displacement (for the vaulter and his pole).

- one energy component is indeed "hidden" in your model, the internal kinetic energy of the vaulter, which comes from movements of the different body parts relative to the center of mass (the vaulter is not a solid). The determination of this energy requires a recording of the speed of all parts of the body (feet, kness, hands, ...) and is usually treated in biomechanical studies for sprint. This component could be important when considering the effect of the knee drive at take off, and the swing style.

- when computing the change in potential energy, one must consider the vertical displacement of the center-of-mass of the vaulter instead of the height cleared. For instance, for Bubka, a 6.40m center-of-mass height would yield a 5.30m vertical displacement only, as the center of mass stands around 1.10m initially, not on the ground.

If you want to go further with this project, I think you might want to contact Julien Morlier from Bordeaux, who did his PhD on 3D analysis of PV and has published some articles on that matter:
http://www.incia.u-bordeaux1.fr/spip.php?article94

Canag

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby willrieffer » Wed May 21, 2014 11:24 am

canag wrote:I usually don't post on threads about vaulting technique, as I am not a PV coach. But I know some physics (teaching at university) so I'll join this discussion!

Your approach seems interesting to compare different vaulters efficiency from objective statements. I have some comments about the model:

- "an almost hidden amount of energy being controlled by gravity" There is no "hidden" energy controlled by gravity, the only change in energy due to gravity is center-of-mass vertical displacement (for the vaulter and his pole).

- one energy component is indeed "hidden" in your model, the internal kinetic energy of the vaulter, which comes from movements of the different body parts relative to the center of mass (the vaulter is not a solid). The determination of this energy requires a recording of the speed of all parts of the body (feet, kness, hands, ...) and is usually treated in biomechanical studies for sprint. This component could be important when considering the effect of the knee drive at take off, and the swing style.

- when computing the change in potential energy, one must consider the vertical displacement of the center-of-mass of the vaulter instead of the height cleared. For instance, for Bubka, a 6.40m center-of-mass height would yield a 5.30m vertical displacement only, as the center of mass stands around 1.10m initially, not on the ground.

If you want to go further with this project, I think you might want to contact Julien Morlier from Bordeaux, who did his PhD on 3D analysis of PV and has published some articles on that matter:
http://www.incia.u-bordeaux1.fr/spip.php?article94

Canag


Well, what I am speaking of in "hidden" energy is pole deflection caused by gravity and the vaulters relation to it in swing angle. During pole compression, as the vaulters swing angle progresses gravity slows the swing more and compresses the pole less. 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. Keep their CoM back and down, elongate the swing, brake the hips through the torso and arms, etc. In the way a springboard diver wants to contact the board perpendicular to gravity for max effect and not have energy "loss" versus potential energy in spin, so to does a vaulter want to keep a similar relation to the pole during compression for maximum effect. The vault is made more complex because the vaulter does have to rotate or swing for max effect.

In action/reaction, the totality of biomech effort has to come out as potential energy as height. Here we are trying to work backward to see how much those differences are in swing action and energy. And thanks to you we are going to find out those are going to be even smaller. One problem to be considered with the biomech action is as an action/reaction arrangement limited by the "window" of acceptable CoM placement in relation to the gravity and the resolution of the gravity vector resolved in swing moment and pole compression based on the vaulter swing angle during pole compression and with the pole as the only action/reaction point outside of the vaulter once they leave the ground. Once decompression starts the vaulter is now much more capable of displacing their CoM as the early compression action has "set" the values of pole speed, energy, angle, etc., and now they can use force through the decompressing pole which rests in the general stability of the box.

In noting CoM displacement, you are correct. Physics is hard and mistakes and oversights are common to me! LOL. For our purposes here, since Lavillenie (1.76m) is shorter he should have a lower CoM and would see a greater gain over Bubka (1.88m) if we adjusted for this oversight. IN the overall this is going to change the joule total and send us more toward the general dominance of take off velocity. PE = mgh Bubka = 80kg x 9.8 m/s/s x 1.1m = 862.4j then we subtract from his 5018j PE total and get 4155.6j for a theoretical 6.4m CoM height for clearance (for which we are still neglecting that the CoM is inside the body). For this we get a PE/PK of 4155.6j/3920j = 106% And for Lavillenie PE = 67kg x 9.8 m/s x 1.04m = 682.9j and 4192j - 682.9j = 3509.1j and PE/PK = 3509.1j/3246j = 108%

Thanks for the link. I will certainly check it out.
Will

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby willrieffer » Wed May 21, 2014 11:45 am

Abstracts of Morlier

Abstract

Current studies on pole-vaulting focus mostly on energy transfer data [Ekevad, M., Lundberg, B., 1995. Simulation of “smart” pole vaulting. Journal of Biomechanics 28, 1079–1090; Ekevad, M., Lundberg, B., 1997. Influence of pole length and stiffness on the energy conversion in pole-vaulting. Journal of Biomechanics, 30, 259–264; Linthorne, N.P., 2000. Energy loss in the pole vault take-off and the advantage of the flexible pole. Sports Engineering 3, 205–218; Schade, F., Arampatzis, A., Bruggemann, G.P., 2006. Reproducibility of energy parameters in the pole vault. Journal of Biomechanics 39, 146–147.] and often fail to take into account the actions exerted on the pole [Arampatzis, Schade, Bruggemann, 2004. Effect of the pole–human body interaction on pole-vaulting performance. Journal of Biomechanics 37, 1353–1360]. The present study integrates the 3D kinematics data of the athlete but also the actions measured at the end of the pole in the planting box and on the track during the last stride before take-off. It proposes a mechanical model allowing determination of the pole-vaulter's actions on the pole. The model is based on a global mechanical approach. The pole-vaulter's action on his upper and lower hand is concentrated on one middle point to solve the dynamics problem. The model was applied to seven experienced pole-vaulters. The force and the moment exerted on the pole by the pole-vaulter during the last stride before take off and during jump stage, were calculated. This analysis of the compressive force and bending moment for seven pole-vaulters helps to highlight the impact of the moment in the performance. The conclusion is confirmed by an additional comparative study carried out on two pole-vaulters, with comparable morphologies and performing with the same pole.

Abstract

A method to determine the three orthogonal components of the angular momentum of a human body about its center of gravity is applied to the pole-vault. The angular momentum and the pole force are used in the analysis of pole-vaulting and are also compared with Gros's data (1982, Ph.D. thesis, University of Alberta) and Hubbard and Barlow's results (1980, Proc. Biomechanics Symp. Indian State Board of Health, pp. 33–48). This study tries to show how such results can be useful in many sporting activities and are necessary for optimization of athletic movement.

Interesting stuff it appears, particularly the first one. Don't know when I'll be getting back issues of JAB...

Will

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby willrieffer » Wed May 21, 2014 12:23 pm

canag,

FWIW...

Dossevi's radical 5.75m clearance at the U23 meet is a visible point of contention in these thoughts. IN radical he initiates pole bend before his take off foot reaches the ground! He left locks to keep his hips back throughout, presents a better relation to gravity as such, as is able to finish the vault. For most vaulters in most styles and forms in history this method would be disastrous. Reaching such an "under" mark would destroy their posture and throw their hips forward and tilt their torso back resulting in what I call a swing progressed take off. The change in gravity vector resolution dooms the vault...

Will

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby altius » Sun May 25, 2014 2:38 am

The real truth is that if you put garbage in you will get garbage out. Try plugging a performance of 6.30m in for Bubka instead of 6.15m and you will get a different result from all of the calculations that different folk are doing at the present time to try and prove Lavellenie was more efficient than Bubka. And Bubby could have jumped 6.30m almost any day he wanted to from 1990 onwards until his achilles tendon injury stopped him jumping. Ask Petrov or Bubka himself and they will both tell you with absolute honesty that he was jumping that high in training but was more interested in setting his family up financially than merely setting world records. Even in 1986 when I first met Vitali, he told me that Sergei was jumping 6.20 in training.

Now I know that this will make no difference to you and your pointless discussion, after all during the middle ages one of the most vexed questions was "How many angels can sit on the head of a pin". But some readers may find some common sense interesting.

And like me, these 'neutrals' will have noticed that the major contributors to this debate have never accepted my challenge to put up film of their own athletes. But theorising is alway easier than actually coaching - that really does test your knowledge of the event.
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 PVstudent » Sun May 25, 2014 11:51 am

It was six men of Indostan, to learning much inclined,
who went to see the elephant (Though all of them were blind),
that each by observation, might satisfy his mind.

The first approached the elephant, and, happening to fall,
against his broad and sturdy side, at once began to bawl:
'God bless me! but the elephant, is nothing but a wall!'

The second feeling of the tusk, cried: 'Ho! what have we here,
so very round and smooth and sharp? To me tis mighty clear,
this wonder of an elephant, is very like a spear!'

The third approached the animal, and, happening to take,
the squirming trunk within his hands, 'I see,' quoth he,
the elephant is very like a snake!'

The fourth reached out his eager hand, and felt about the knee:
'What most this wondrous beast is like, is mighty plain,' quoth he;
'Tis clear enough the elephant is very like a tree.'

The fifth, who chanced to touch the ear, Said; 'E'en the blindest man
can tell what this resembles most; Deny the fact who can,
This marvel of an elephant, is very like a fan!'

The sixth no sooner had begun, about the beast to grope,
than, seizing on the swinging tail, that fell within his scope,
'I see,' quothe he, 'the elephant is very like a rope!'

And so these men of Indostan, disputed loud and long,
each in his own opinion, exceeding stiff and strong,
Though each was partly in the right, and all were in the wrong!

So, oft in theologic wars, the disputants, I ween,
tread on in utter ignorance, of what each other mean,
and prate about the elephant, not one of them has seen!
John Godfrey Saxe

Six blind men describe an elephant.jpg
Six blind men describe an elephant.jpg (49.22 KiB) Viewed 14465 times


Thank you CANAG for trying to make Willreifer see some sense. Unfortunately he has missed the point and still does not appear to understand two fundamental facts concerning the vector of gravitational force and its line of action.
1. Gravitational force in the gravitational field of the earth at all times produces an acceleration of approximately 9.81 m/s/s in the downward direction (local position on the planet does influence the exact acceleration magnitude, but for practical purposes this variation will have very minor effect upon a pole vaulter).

2. The gravity vector does not possess, by definition, a component in the horizontal direction.

The so called calculations of the potential energy of a vaulter being calculated on the basis of an average horizontal velocity in the 10m to 5m final interval of the approach run CAN NOT BE the actual VELOCITY or its DIRECTION of any vaulter at the instant of take-off.

Also the potential energy (PE) of the vaulter's centre of mass (COM) above the ground must be included in the PE calculation as does the PE gain of the COM from it's height at pole release to its peak height at which point the vaulter's potential energy above the take-off surface will be a maximum.

In terms of the total energy at peak height their will be some energy required to continue to translate and rotate the vaulter that must be factored into the energy calculation.

Total energy, or any energy comparisons, to determine efficiencies between the vaulter must use the ratio of energy per unit body mass (J/kg) and not the absolute value (J).

Correlation of Average approach run velocity to successful vault height clearance is an indication of the relationship between the two numbers. A correlation does not mean the relationship is a causative one. Indeed in the homogeneous population of male and female pole vaulters the amount of variation in the numbers (r x r) explained is relatively small and insufficient to be predictive of the outcome of the vault clearance height. Technical and Psychological factors are much greater determinants of the results outcome in comparison to average horizontal final approach velocity for elite vaulters!

No vaulter can have an efficiency of 100%, let alone greater than 100%. To do this a vaulter would be defying the Laws of Conservation of Energy and the Second Law of Thermodynamics! I think vaulting coaches are more concerned with continuous motion, and not perpetual motion, in the pole deflection and recoil phases of real world pole vaulting.

The attempt to show that Vaulter A is superior to Vaulter B using contrived / bogus data and a limited perspective as to the mechanics of pole vaulting is not only time wasting for coaches who want to understand the event but is irritating, especially when ill-informed and irrational claims are being made based on conjecture and mind games by some who are as silly as the men of Indostan!

By the way it just so happens that Bubka and Trandenkov have been studied in the same competition by reputable scientists and in my next post I will put up some of the data they reported in regard to energy exchanges in their vaults on that occasion.

In regard to pre-bending the pole by Dossevi (in particular) and the assertions concerning the uniquesness of Lavillenies vaulting technique ,I have some factual matter to put up for readers to consider in judging the veracity of some assertions being made by Willreifer and others.

I leave readers with real data from a real jump by Mike Tully in 1978. Mike Tully ,I believe, could be considered as a pioneer continuous "swinger" throughout the pole deflection and recoil support phase of the vault.

Mike Tulley take-off pole bending data diagram.jpg
Mike Tulley take-off pole bending data diagram.jpg (57.41 KiB) Viewed 14465 times


Many coaches in the USA, France, Poland, Former East Germany and the Soviet Union around this time were very aware of the necessity to "swing continuously with vigour throughout the pole support phases" but had not fully understood the mechanism of bending the pole with minimal energy losses and successfully finish the pole plant and take-off. The Petrov - Bubka revolution in the approach run, pole plant and take-off technique was being revealed to the world 1983-84. The key elements were identified in the Petrov seminal paper in Birmingham, England in 1985. The rest is history.

If this thread is anything to go by the lessons of the past history of flexible pole vaulting have still not been understood, let alone practiced.

Is it me... but Willreifer's contributions, as the weeks go by, appear to me to bear more and more resemblance to those of PVdaddy but with less abrasive "attitude"? Some of the questions, purportedly from pm's appeared suspiciously like Dorothy Dixers!
Every new opinion at its starting, is precisely a minority of one!

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby PVDaddy » Sun May 25, 2014 7:31 pm

First of all I would like to assure the readers that Willreifer's contributions are entirely his own. I commend him and David for recognizing the vastly different approaches to the utilization of the gravity vector that Lavellenie applies as compared to Bubkas approach. I would also like to point out the fact that it was David and not PVStudent who recognized this potential early on before Lavellenie recently set the World Record! As I began to look into it for myself (With an open unbiased mind) and examine Lavellenies method as compared to Bubkas, I felt that there was perhaps great validity to their claims. I suggested that it would be interesting and perhaps beneficial to attempt to determine swing efficiency during pole support and suggested perhaps a crude but introductory method for moving in that direction. I will confess that Physics is not my major area of expertise as I only had 3 Physics courses in College and honestly forgot most of it these 29 years later. However, I do believe it was a decent effort based on my confessed limited abilities in the right direction. It was my earnest hope that Will and perhaps others more advanced in this area could fill in the blanks and move this attempt forward. At least Canag found our attempt to be interesting and suggested some other points we failed to consider and provided some additional tools. You on the other hand PVstudent , rudely begin by slandering us with your nursery rhyme and equate us to blind men and then try to claim your first 3 points as your own, when in fact all you have done is paraphrase the points Canag has already made? I suggest, no in fact challenge you PVstudnet to make a better attempt to compare lavellenies swing efficiency to Bubkas. This is after all the goal and effort of this thread. Show us your work and show us the data you use, specifically starting COG height and take off velocities of both vaulters. Show us were you collected your data on both vaullters and point us to the website that you collected it from so all can see as Will has. I may be just a simple man, but I'm smart enough to know that Renauld Lavellenie and not Sergey Bubka is the current world record holder. I'm also smart enough to know that if one vaulter is shorter (I believe somewhere around 5 Ft. 9 in. compared to 6 ft. 1 in.) and slower ( I believe around 9.4 M/S as compared to 9.8 M/S) they are immediately at a mechanical disadvantage going into the pole support phase and that Lavellenie has to be making it up there. I am confident that if you use correct and unbiased data and good Physics your numbers will bare out the fact that Lavellenie method (and it is radically different then Bubkas!) is more efficient in the pole support phase J/Kg or otherwise. Actually, I believe it is you and Altius that are the ones who are conveniently blinded to the Lavellenie Elephant in the room as the glasses you ware are tinted with a glaze of Petrov (I am also a big fan of, but am also open to other methods) telling you it is the only efficient method to vaulting or setting World Records. This is not surprising as you both are financially and personally invested in this book to sell ( Financial gain seems to be your greatest motivation here and its getting stale to many, as is your rude behavior to anyone else thinking outside of your box). I just recently made it clear that I was PM others in my post in regard to the Lavellenie method as I was sincerely trying to advance my knowledge, while avoiding the public abuse you both continue to dish out as an ongoing disguise to promote your book, so quit pretending to be Sherlock Homes! We will all be patiently waiting for the unbiased, correct, Physics analysis, comparing the pole support efficiencies of Bubka and Lavellenie!
Every jot and every tittle adds up to more than just a little.


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