Pole Vault Manifesto

[volteur]

Agapit, ta.

I believe it is general knowledge that once an athlete leaves the ground they lose the ability to impart any more energy into the jump. As soon as they leave the ground gravity also begins to take energy away from the jump. As soon as.

By this thinking any time spent off the ground before the athlete arrives into the pole is time spent losing energy. I realise the free takeoff does not have this as part of its description but i think the pre jump does.

Surely Petrov would not say the free take off is the same as the pre-jump.

[altius]

"I believe it is general knowledge that once an athlete leaves the ground they lose the ability to impart any more energy into the jump." I just have to point out that that knowledge has not reached us in Australia - thank goodness.

Perhaps you are confusing the pole vault - where the athlete is still in contact with the ground for most of the vault -albeit through the pole - and the long jump where they clearly have no contact with the ground and certainly cannot add any energy to the system after they leave the ground.

Please remember we are a bit backward down so here when you explain why I am incorrect please use small words and short sentences.

[volteur]

altius-"I believe it is general knowledge that once an athlete leaves the ground they lose the ability to impart any more energy into the jump." I just have to point out that that knowledge has not reached us in Australia - thank goodness.

me-You guys aren't that far behind! Seriously though you can't argue with that point so comedy suffices i guess.


al-"Perhaps you are confusing the pole vault - where the athlete is still in contact with the ground for most of the vault -albeit through the pole - and the long jump where they clearly have no contact with the ground and certainly cannot add any energy to the system after they leave the ground.

me-No confusion at all. My main point is that any time spent between leaving the ground and gaining pressure or weight or contact with the ground through the pole is a 'losing' energy to gravity situation. A continuous chain or transfer of energy would imply to me that no such loss should be occurring.

al-"Please remember we are a bit backward down so here when you explain why I am incorrect please use small words and short sentences."

me-"Firstly, is this your own theory? Secondly, I discovered your main thing was to be a university lecturer so my assumption following that discovery is you are being sarcastic. Do i have that right? Double sarcasm in my first ever post from you?

cheers

Volteur

[AeroVault]

I believe it is general knowledge that once an athlete leaves the ground and before the pole begins to bend they lose the ability to impart any more energy into the jump. As soon as they leave the ground gravity also begins to change energy in the jump. As soon as.

edited.

I to believe this edited version to be true. If there is no force on the pole, then there is nothing acting on the system (vaulter and pole) besides gravity. Gravity will change some of the vertical kinetic energy of the vaulter into potential energy from their increased height, but since there are no outside forces, no energy is lost. The real gain from a pre-jump (as well as free takeoff) is the improvement in takeoff angle. You can rotate the pole closer to vertical without any loss in energy, which makes the rest of the vault so much more efficient.

[volteur]

I believe it is general knowledge that once an athlete leaves the ground and before the pole begins to bend they lose the ability to impart any more energy into the jump. As soon as they leave the ground gravity also begins to change energy in the jump. As soon as.

edited.

I to believe this edited version to be true. If there is no force on the pole, then there is nothing acting on the system (vaulter and pole) besides gravity. Gravity will change some of the vertical kinetic energy of the vaulter into potential energy from their increased height, but since there are no outside forces, no energy is lost. The real gain from a pre-jump (as well as free takeoff) is the improvement in takeoff angle. You can rotate the pole closer to vertical without any loss in energy, which makes the rest of the vault so much more efficient.

Thanks and i agree with the edited version as well, except there is this new dilemma. You don't gain any extra energy once the transfer from the body into the pole occurs. All that one can do here is be as efficient as possible to minimise the loss.

I agree also that the takeoff angle should be optimised. The closer one can get it to the vertical during the takeoff phase the better. We are talking about the cord length of the pole here aren't we. The actual length of the pole is not the thing we are trying to get to vertical because that would be stiff pole technique. So to get the cord length as deep as possible is more of the what the primary intention of the takeoff should be i feel. Extension at takeoff through the posture is but one of the factors leading to a successful takeoff is it not? There are others. All of those factors lead up to getting the cord length as deep as possible after takeoff. Of course the pole must be bent to have a cord length different from it's actual length and this requires some bending of the pole before resistance is met.

cheers

Volteur

[AeroVault]

Thanks and i agree with the edited version as well, except there is this new dilemma. You don't gain any extra energy once the transfer from the body into the pole occurs. All that one can do here is be as efficient as possible to minimise the loss.

Once the pole contacts the back of the box, you no longer have a closed system and can gain (or lose) energy. This is where the swing comes into play. This has been discussed earlier in the thread, but you can add a great deal of energy from an aggressive swing.

We are talking about the cord length of the pole here aren't we. The actual length of the pole is not the thing we are trying to get to vertical because that would be stiff pole technique.

When I said rotate the pole to vertical, I am referring to the chord. However, at the takeoff, stiff pole technique is identical to bent pole vaulting. I was stressing that you can achieve a better takeoff angle before the pole begins to bend. Starting with the pole that much closer to vertical (even if it's a small amount) allows the vaulter to use a stiffer pole while safely penetrating to the middle of the pits. Big poles = quicker return of energy and higher pushoff.

Hope that makes sense.

[volteur]

Once the pole contacts the back of the box, you no longer have a closed system and can gain (or lose) energy. This is where the swing comes into play. This has been discussed earlier in the thread, but you can add a great deal of energy from an aggressive swing.

When does the pole resistance begin in this version of the takeoff?

When I said rotate the pole to vertical, I am referring to the chord. However, at the takeoff, stiff pole technique is identical to bent pole vaulting. I was stressing that you can achieve a better takeoff angle before the pole begins to bend. Starting with the pole that much closer to vertical (even if it's a small amount) allows the vaulter to use a stiffer pole while safely penetrating to the middle of the pits. Big poles = quicker return of energy and higher pushoff.

Hope that makes sense.

I'm glad you were talking about the chord but since we are talking about prior to the pole bending it's not really relevant. If we were talking about not meeting resistance until after the pole is bent that would be another story.

Going back to an earlier point you made about how the force of gravity gives the vaulter potential energy as he loses kinetic energy after leaving the ground. How do you see this helping the vault?

And one final bit, it's not about the size of the pole, it's about how you use it isn't it? Seriously it's the differential between the vaulter's weight and the size of the pole that is important in the release and clearance phase isn't it?

[dj]

hello

Seriously it's the differential between the vaulter's weight and the size of the pole that is important in the release and clearance phase isn't it?

maybe... but not as a catapult......

Big poles = quicker return of energy and higher pushoff.

No..........

i'm of the opinion that it is the swing, continous and accelerated, that gives the height above the grip..

the pole is not a catapult..........

what the "recoil" of the pole does is lighten the "load" or weight of the body by lifting the jumper,,,(not thrusting the jumper.).. creating less pull against gravity.. the vaulter has to thrust himself.. with the swing..

t-mack was extremely good at that phase.. his 1.21m above his grip came from that move.. he practices it.. and calls it a "superman"..


dj

[vault3rb0y]

Nevermind the physics of adding energy into the vault, which you claim cannot be done.

http://www.polevaultpower.com/forum/vie ... c&start=36

There was a study from the Seol Olympics by Germans in which Egorov and Bubka were proven to have increased their energy input into the pole during the second phase of their jump (after they leave the ground). How do you explain this, were the germans wrong?

Granted, only two vaulters at the olympics were able to add more energy than they lost, so obviously a large amount of energy is lost in the vault by almost all vaulters in the world. But saying that the swing adds no energy and that we should focus on JUST conserving it after we leave the ground is wrong, we should do both.

it's the differential between the vaulter's weight and the size of the pole that is important in the release and clearance phase isn't it?

Not really.... the vaulters focus is to put as much energy into the pole as possible. If they do this well, they need a bigger pole or they blow through, but you are still adding the same amount of energy into a pole regardless of the size of the pole. You are confusing intentions and result. One of the intentions is to add as much energy into a pole as possible, and the result is needing stiffer poles. But if you dont swing hard and energy energy into a stiffer pole, it wont give you a much back anyway. You can still jump high on softer poles if you slow down your pole speed or lower your grip, because your energy input after you leave the ground should be the same.

[AeroVault]

When does the pole resistance begin in this version of the takeoff?

In every version of the takeoff it starts the instant the pole tip hits the back of the box. Some may argue that the system is not closed prior to that since the pole is already touching the bottom of the box, but in all practicality, you can begin to add energy to the system once the pole tip makes contact with the back.

Going back to an earlier point you made about how the force of gravity gives the vaulter potential energy as he loses kinetic energy after leaving the ground. How do you see this helping the vault?

It's not really helping or hurting per se, but you just don't want to lose that energy. What helps is having the higher takeoff angle. To clear the highest height possible, you want to convert the maximum amount of kinetic energy into potential energy. Kinetic comes from the things we talked about before... run, swing, pushoff. Potential is just you sitting at some height above the surface of the Earth (you have the potential to fall back down). The higher you are, the more potential energy you have. It is okay to convert that energy at takeoff since you would have to at some point in the vault anyway. You don't want to lose your forward kinetic energy since that is what helps get the chord of the pole to vertical.

[AeroVault]

Big poles = quicker return of energy and higher pushoff.

No..........

i'm of the opinion that it is the swing, continous and accelerated, that gives the height above the grip..

the pole is not a catapult..........

what the "recoil" of the pole does is lighten the "load" or weight of the body by lifting the jumper,,,(not thrusting the jumper.).. creating less pull against gravity.. the vaulter has to thrust himself.. with the swing..
dj

With all due respect, I don't see how "lifting" is different than "thrusting". Regardless of the term used, it is an upward force on the vaulter who is completely inverted and no longer swinging. I absolutely agree with you that the swing gives some vertical velocity to the vaulter, and starts them in the right direction. I simply said that a bigger pole (meaning stiffer) would return energy quicker. Once the vaulter is inverted, additional height comes from their initial upward velocity (from the swing), their pushoff, and the force returned from the pole. A stiffer pole bent the same amount as a softer one will contribute a larger force - pure physics.

[dj]

yep