Effective Clearance?
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And if a significant part of the flyaway is attributable to the speed/power of the sing-up, what can a vaulter do to better expoit that?
The speed and power of the swing IS the reason for a huge flyaway. The discussion above about stiff polers using a fast swing to achieve incredible flyaways is dead on. Their poles gave them absolutely no help.
Obviously sound technique throughout the jump, as you mentioned, is imperative. You're only trying to cheat gravity, right? What's the pull of gravity? Can your boy run that fast at takeoff with no resistance from the pole? Very few in this world can. Is it possible for him to develop the ability to swing faster than the pull of gravity? Of course.
Fiberglass, carbon, whatever poles are only an advantage because they allow the vaulter to hold higher. You'll drive yourself crazy and drain your wallet trying to find "the" pole. Develop "the vault" and the right pole becomes less important. He'll have a huge flyaway on a broom stick.
good morning
thanks AVC and ladyvolscoach..
the amount of "fly' above the grip is proportionate to the speed on the runway.. which should determine grip.. that grip will determine the swing radius and the speed in which it is done will determine the "potential" height above hand grip.
off course a seasoned vaulter can grip a lower grip and many times increase the "fly' above the "norm".
the normal "fly" above grip is indicated with my "MID" chart by doing the math from the grip to bar height, taking into account the box depth..
the "fly" is speed and distance related... and if the vaulter "blocks" and/or gets "caught" under it effects the swing speed dramatically.. causing the lose of pole speed and the vaulter to "sit" on the pole or not make the pit...
later
dj
thanks AVC and ladyvolscoach..
the amount of "fly' above the grip is proportionate to the speed on the runway.. which should determine grip.. that grip will determine the swing radius and the speed in which it is done will determine the "potential" height above hand grip.
off course a seasoned vaulter can grip a lower grip and many times increase the "fly' above the "norm".
the normal "fly" above grip is indicated with my "MID" chart by doing the math from the grip to bar height, taking into account the box depth..
the "fly" is speed and distance related... and if the vaulter "blocks" and/or gets "caught" under it effects the swing speed dramatically.. causing the lose of pole speed and the vaulter to "sit" on the pole or not make the pit...
later
dj
Come out of the back... Get your feet down... Plant big
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ladyvolspvcoach
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bending pole
If the swing is the only or main thing that affects the effective clearance then why don't we all get on soft poles and jack up our grips and swing like h*$l ?
Not a bad thought.
If you believe that the pole is a catapult then getting on bigger and bigger poles makes sense. But if you believe that the purpose of the pole bending is to shorten the chord of the pole and allow vaulters to hold higher then the softer pole make sense......Hmmmmmm! Wonder which it is!!! Or is it both!!!!
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altius
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I hope -
1. The following will help clarify this issue
2. Becca wont mind me doing this
3. Folk wont complain that I simply promoting BTB2
This is the introduction to Chapter 7
CHAPTER SEVEN: Biomechanics, Technical models and Style.
An athlete’s style - overlays their technical model - which should be based on the principles of biomechanics! Alan Launder 2003
The biomechanics of flexible pole vaulting.
In the stiff pole era the limiting factor in performance at the elite level was the height an athlete could grip on the pole and still drive it to the vertical. Although Warmerdam managed to grip at 4.05 on his best jumps, the average grip height for the best vaulters of this period was approximately 3.81m. However they could generally achieve differentials – the difference between their grip height and the height of the bar cleared – of over 30 inches. In fact Doherty stated that some stiff pole vaulters had cleared as much as 39 inches higher than their hold on the vaulting pole, something that many modern athletes would be happy to achieve. This was a tribute both to their athleticism and to the efficiency of the long swing of the entire body around the hands in converting horizontal velocity into vertical speed.
However in the rush to exploit the potential of the flexible pole, the efficiency of the stiff pole vaulters, with their emphasis on a continuous swing from take off until pole release, appears to have been forgotten. To some extent this was understandable, because at the time it seemed that a pole that could ‘catapult’ the vaulter above the bar was verging on the magical! Indeed as legions of athletes using flexible poles surpassed the performances of the great athletes of the stiff pole era, the catapult myth seemed to be confirmed.
Unfortunately this has tended to overshadow the major advantage of the flexible pole – that it enables the vaulter to significantly increase their grip height! As we suggested in Chapter Five, it may help coaches to understand the significance of this if they stop thinking of the flexible pole – as a single flexible pole!
So as the actual pole flexes, the chord of the pole (The Cpole) shortens; this means that it will rotate towards the pad more quickly. So when Bubka took off, his actual pole was 5.20 metres/ 17’long. Even with his great speed and excellent take off he could never have moved that pole to the vertical - unless it started to shorten once he left the ground! As it was, the pole began to flex after take off and the Cpole rapidly and progressively shortened until it was for an instant, only 3.83metres long! Then, again almost magically, it immediately began to straighten back to its original 5.20 metres. It was almost as if the vaulter could lower their grip through the early phases of the vault and then raise it again as they approached the bar. Figure 7.1
(with Figure 7.2). SEPARATE PAGE
A summary of the advantages of the flexible pole.
1. It gives the vaulter an infinite number of poles of differing lengths. As the pole shortens it reduces the effective length of the chord – biomechanical pole – so that it will rotate faster towards the vertical.
2. It stores some of the initial energy of motion as strain energy in the fibres which make up the pole. Some of this energy can be recovered to add to the vaulters vertical velocity.
3. The flexing pole acts like a shock absorber.
4. It allows the vaulter to keep their centre of mass low in the initial phase of the vault.
5. It enables the athlete to increase the amplitude of the whip swing phase.
6. Because the shortening pole rotates rapidly towards the bar, it allows the vaulter to move into a much more vertical position than was possible for the stiff pole vaulter.
7. It is lighter than an equivalent length steel pole; a big advantage for youngsters - especially girls.
All of these factors interact in a complex fashion to allow the vaulter to grip higher than they could on a stiff pole.
While some of the advantages of the flexible pole, such as the shortening of the chord, are easy to understand, some are more complex. For example -
,
1 One of the most misunderstood issues in pole vaulting is the way a flexible pole stores some of the energy that has caused it to flex as strain or potential energy, and can then return some of that energy (as kinetic energy) to the vaulter as it straightens. Early fibre glass vaulters appeared to believe that this catapult effect was the major - perhaps the only - advantage of the new pole. There is certainly nothing in the literature of the time which indicates that they were aware of the importance of the shortening Cpole in improving performance.
On the other hand some modern coaches completely discount any acceleration from the straightening of the pole. This is understandable if we consider a vaulter using a pole at, or slightly above their body weight, because in that case the pole will straighten so slowly as to have a negligible effect on the athlete’s speed.
However if the vaulter – as in Bubka’s case – is using a pole 22kilograms/ 44 lbs above their body weight, the situation changes. To shorten the Cpole from 5.20m to 3.83m in a 10.8 flex pole clearly takes immense energy – in fact very few other vaulters in history would have been able to effectively bend the pole Bubka used to set his world records. They simply could not generate and direct the enormous energy required to do it! Now we know that while energy can be transformed from one state to another it cannot simply disappear, so once energy is stored in the fibres of a pole it stays there until it is released – that is as the pole straightens or it breaks. In fact some indication of the potential energy stored in a fully flexed pole is provided when a pole does break. On one occasion Alan found the pole tip over 100 metres away from the box after a relatively small pole broke, and on another occasion he saw the intense deep bruising on Victor Chystiakov’s back after he was hit by fragments of a much larger pole when it broke. However he had to take Victor’s word for the fact that he was urinating blood for several days afterwards because the impact had damaged a kidney!
So what does happen to the energy stored in the pole during a vault? We believe that it may clarify the situation, if instead of thinking of a catapult effect we think in terms of the straightening speed of the pole.
With this in mind it may be easier to understand that the speed with which a pole straightens depends on the energy stored in it - and the mass it has to move. In simple terms this comes down to the difference between the rated stiffness of the pole and the weight of the vaulter. So a vaulter like Tom Lovell, Figures 7.3a and b, who weighed 140 lbs and was jumping on a 15’ 185lb pole, i.e. a differential of 45 pounds – is likely to find the pole straightening much more quickly than it would if he had weighed 180lbs - or conversely the pole was rated at 140lbs.
In the first scenario the pole is straightening fast enough to provide a launch platform for Tom as he pulls, turns and pushes on it to accelerate himself upwards. If he has correctly timed this interaction with the pole, the summation of the forces from the straightening pole are added to his muscle power and will generate sufficient vertical speed to make it seem that he is being catapulted from the top of the pole and over the bar.
1. The following will help clarify this issue
2. Becca wont mind me doing this
3. Folk wont complain that I simply promoting BTB2
This is the introduction to Chapter 7
CHAPTER SEVEN: Biomechanics, Technical models and Style.
An athlete’s style - overlays their technical model - which should be based on the principles of biomechanics! Alan Launder 2003
The biomechanics of flexible pole vaulting.
In the stiff pole era the limiting factor in performance at the elite level was the height an athlete could grip on the pole and still drive it to the vertical. Although Warmerdam managed to grip at 4.05 on his best jumps, the average grip height for the best vaulters of this period was approximately 3.81m. However they could generally achieve differentials – the difference between their grip height and the height of the bar cleared – of over 30 inches. In fact Doherty stated that some stiff pole vaulters had cleared as much as 39 inches higher than their hold on the vaulting pole, something that many modern athletes would be happy to achieve. This was a tribute both to their athleticism and to the efficiency of the long swing of the entire body around the hands in converting horizontal velocity into vertical speed.
However in the rush to exploit the potential of the flexible pole, the efficiency of the stiff pole vaulters, with their emphasis on a continuous swing from take off until pole release, appears to have been forgotten. To some extent this was understandable, because at the time it seemed that a pole that could ‘catapult’ the vaulter above the bar was verging on the magical! Indeed as legions of athletes using flexible poles surpassed the performances of the great athletes of the stiff pole era, the catapult myth seemed to be confirmed.
Unfortunately this has tended to overshadow the major advantage of the flexible pole – that it enables the vaulter to significantly increase their grip height! As we suggested in Chapter Five, it may help coaches to understand the significance of this if they stop thinking of the flexible pole – as a single flexible pole!
So as the actual pole flexes, the chord of the pole (The Cpole) shortens; this means that it will rotate towards the pad more quickly. So when Bubka took off, his actual pole was 5.20 metres/ 17’long. Even with his great speed and excellent take off he could never have moved that pole to the vertical - unless it started to shorten once he left the ground! As it was, the pole began to flex after take off and the Cpole rapidly and progressively shortened until it was for an instant, only 3.83metres long! Then, again almost magically, it immediately began to straighten back to its original 5.20 metres. It was almost as if the vaulter could lower their grip through the early phases of the vault and then raise it again as they approached the bar. Figure 7.1
(with Figure 7.2). SEPARATE PAGE
A summary of the advantages of the flexible pole.
1. It gives the vaulter an infinite number of poles of differing lengths. As the pole shortens it reduces the effective length of the chord – biomechanical pole – so that it will rotate faster towards the vertical.
2. It stores some of the initial energy of motion as strain energy in the fibres which make up the pole. Some of this energy can be recovered to add to the vaulters vertical velocity.
3. The flexing pole acts like a shock absorber.
4. It allows the vaulter to keep their centre of mass low in the initial phase of the vault.
5. It enables the athlete to increase the amplitude of the whip swing phase.
6. Because the shortening pole rotates rapidly towards the bar, it allows the vaulter to move into a much more vertical position than was possible for the stiff pole vaulter.
7. It is lighter than an equivalent length steel pole; a big advantage for youngsters - especially girls.
All of these factors interact in a complex fashion to allow the vaulter to grip higher than they could on a stiff pole.
While some of the advantages of the flexible pole, such as the shortening of the chord, are easy to understand, some are more complex. For example -
,
1 One of the most misunderstood issues in pole vaulting is the way a flexible pole stores some of the energy that has caused it to flex as strain or potential energy, and can then return some of that energy (as kinetic energy) to the vaulter as it straightens. Early fibre glass vaulters appeared to believe that this catapult effect was the major - perhaps the only - advantage of the new pole. There is certainly nothing in the literature of the time which indicates that they were aware of the importance of the shortening Cpole in improving performance.
On the other hand some modern coaches completely discount any acceleration from the straightening of the pole. This is understandable if we consider a vaulter using a pole at, or slightly above their body weight, because in that case the pole will straighten so slowly as to have a negligible effect on the athlete’s speed.
However if the vaulter – as in Bubka’s case – is using a pole 22kilograms/ 44 lbs above their body weight, the situation changes. To shorten the Cpole from 5.20m to 3.83m in a 10.8 flex pole clearly takes immense energy – in fact very few other vaulters in history would have been able to effectively bend the pole Bubka used to set his world records. They simply could not generate and direct the enormous energy required to do it! Now we know that while energy can be transformed from one state to another it cannot simply disappear, so once energy is stored in the fibres of a pole it stays there until it is released – that is as the pole straightens or it breaks. In fact some indication of the potential energy stored in a fully flexed pole is provided when a pole does break. On one occasion Alan found the pole tip over 100 metres away from the box after a relatively small pole broke, and on another occasion he saw the intense deep bruising on Victor Chystiakov’s back after he was hit by fragments of a much larger pole when it broke. However he had to take Victor’s word for the fact that he was urinating blood for several days afterwards because the impact had damaged a kidney!
So what does happen to the energy stored in the pole during a vault? We believe that it may clarify the situation, if instead of thinking of a catapult effect we think in terms of the straightening speed of the pole.
With this in mind it may be easier to understand that the speed with which a pole straightens depends on the energy stored in it - and the mass it has to move. In simple terms this comes down to the difference between the rated stiffness of the pole and the weight of the vaulter. So a vaulter like Tom Lovell, Figures 7.3a and b, who weighed 140 lbs and was jumping on a 15’ 185lb pole, i.e. a differential of 45 pounds – is likely to find the pole straightening much more quickly than it would if he had weighed 180lbs - or conversely the pole was rated at 140lbs.
In the first scenario the pole is straightening fast enough to provide a launch platform for Tom as he pulls, turns and pushes on it to accelerate himself upwards. If he has correctly timed this interaction with the pole, the summation of the forces from the straightening pole are added to his muscle power and will generate sufficient vertical speed to make it seem that he is being catapulted from the top of the pole and over the bar.
Its what you learn after you know it all that counts. John Wooden
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AVC Coach
- PV Lover
- Posts: 1386
- Joined: Fri May 23, 2003 9:21 am
- Expertise: Former College Vaulter, Current Coach (All levels)
- World Record Holder?: Renaud Lavillenie
- Favorite Vaulter: Miah Sanders
- Location: Black Springs, Arkansas
- Contact:
If the swing is the only or main thing that affects the effective clearance then why don't we all get on soft poles and jack up our grips and swing like h*$l ?
Good point gtc! I got carried away with expressing my views on the swing and didn't put any emphasis on the stiffness of the pole other than when I alluded to the stiff polers of yesteryear. Yes, the stiffness of the pole accounts for something. You can't expect an energy return from something that's not designed to fully return that energy. A pole that is too soft on a particular jump will only absorb and disperse that energy, sometimes in shards all over your pit and surroundings.
PVDad2 was wondering how important the swing was in achieving a substancial flyaway. I was simply lobbying for the swing. However, if I wanted to jack my grip, I would have to get on a really soft pole!
AVC, I knew you didn't believe large effective clearances could be achieved on very soft poles. 
I was just feeling a little honery. 
Alan, Beautifully written piece!! That short section of literature in and of itself should be enough for anybody half way serious about this sport to have to add that book to their library!
I was just feeling a little honery.
Alan, Beautifully written piece!! That short section of literature in and of itself should be enough for anybody half way serious about this sport to have to add that book to their library!
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