Can you add energy after takeoff?

[KirkB]

Does it matter?

[sigh]

... it's not just an academic exercise. It has a practical purpose ...

If you believe that your vault is predetermined at takeoff, then you will not see the value in perfecting your swing and your extension.

There is SO MUCH MORE that you can add to your vault after your takeoff, that this belief would hold you back from learning ... and perfecting ... your swing and your extension. ...

So to try ask my question even CLEARER, should you focus ALL of your efforts on raising your CoM by improving your takeoff velocity, or should you focus SOME of your efforts in raising your CoM even higher by manipulating your body on the pole?

I think we can ALL agree that you need to manipulate your body to get upside down on the pole. But is that the ONLY reason to swing? Would your post-takeoff efforts to raise your CoM be in vain ... or not?

Come on guys ... and gals ... the question isn't that tough!

Kirk

[Capt Caveman]

What do you want us to say? Your post seems to point to only the answer you want to see. Since that is the only answer, I want to learn/know what is the right answer?

Simple to one is only simple due to experience, of which I only have a limited amount. I am not a dumb man, I understand a lot of what is being discussed and hope that your not just a novice with a lot of time on your hands. I mean no offense but following many of your posts I feel the urge to question how much of what you post is what I want to apply to what I am doing with my athletes. You obviously have credentials (based on the confidence of your posts) but I have never put my faith in credentials....I put my faith in results wich is why I ask a lot of questions.

[bel142]

After having re-read this discussion, I am more convinced in my first notion, the vaulter cannot add energy into the vault, the energy is already there and maximum energy is predetermined... BUT this does not mean the vault and jump is predetermined. The energy is transferred from horizontal running speed to upward motion, inconsistency in technique detract from energy conversion, hence if you don't swing from 7 all that energy is not going to do you a sack of potatoes amount of good, because you are failing to convert and handle it.

To me this is where the training factor comes in, to exploit every single amount of this potential energy perfection in the vault is needed. Bubka converted energy better than other people from his teqnique. There have been vaulters that are stranger an faster than bubka... Keenan King for one example... super fast doesn't convert that energy very well, doesn't jump super high. (I say that as a relative thing, King jumps a heck of alot higher than i do...) I digress...

[Tim McMichael]

Of course there is a finite amount of energy available to a vaulter, but only in the sense that there is a finite amount of energy available in the universe. From that perspective no one ever "creates" energy. If we want to keep stepping the potential energy links backward I suppose you eventually get to sunlight. (If I remember my Carl Sagan right.)

As I understand it, the point up for debate is whether or not an athlete can, by their actions subsequent to the takeoff, add energy that would not be available had they done nothing but hang on. Your point that the potential energy available through muscular effort is already present seems not to take into account the fact that that potential must be actuated by the athlete. They must, by a conscious act, use the energy in their muscles in such a way as to add force to the total movement. If they do not choose to act, that potential energy will be wasted. It is, therefore, both reasonable and practical to talk about the vaulter's actions after takeoff as adding energy to the vault.

The practical side of the semantics is all that matters. The idea that power can be added to a vault after takeoff is a crucial concept. Much that is dear to us depends on it. Both safety and sound theory can be deduced from this one idea as a starting point. What the athlete does after leaving the ground must add energy to the vault or it is a flawed jump. The quality of the approach and takeoff can be determined by how well they facilitate this possibility. The efficiency of the middle and top of the jump can be judged according to how much power is added. There are also issues concerning the dynamics of the energy distribution between the pole and the athlete that make it so that the most powerful vaults are also the safest. When a vaulter is depending on his swing to get the penetration he needs, it is almost impossible to finish a jump that will not put also him in the center of the pit.

[Tim McMichael]

Of course there is a finite amount of energy available to a vaulter, but only in the sense that there is a finite amount of energy available in the universe. From that perspective no one ever "creates" energy. If we want to keep stepping the potential energy links backward I suppose you eventually get to sunlight. (If I remember my Carl Sagan right.)

As I understand it, the point up for debate is whether or not an athlete can, by their actions subsequent to the takeoff, add energy that would not be available had they done nothing but hang on. Your point that the potential energy available through muscular effort is already present seems not to take into account the fact that that potential must be actuated by the athlete. They must, by a conscious act, use the energy in their muscles in such a way as to add force to the total movement. If they do not choose to act, that potential energy will be wasted. It is, therefore, both reasonable and practical to talk about the vaulter's actions after takeoff as adding energy to the vault.

The practical side of the semantics is all that matters. The idea that power can be added to a vault after takeoff is a crucial concept. Much that is dear to us depends on it. Both safety and sound theory can be deduced from this one idea as a starting point. What the athlete does after leaving the ground must add energy to the vault or it is a flawed jump. The quality of the approach and takeoff can be determined by how well they facilitate this possibility. The efficiency of the middle and top of the jump can be judged according to how much power is added. There are also issues concerning the dynamics of the energy distribution between the pole and the athlete that make it so that the most powerful vaults are also the safest. When a vaulter is depending on his swing to get the penetration he needs, it is almost impossible to finish a jump that will not put also him in the center of the pit.

This is what happens when you cross an english literature major and a pole vaulter---- from the wifey

[altius]

Couldnt be explained better Tim! But it is rather sad that after all of the information,knowledge and even wisdom, that has been put up on this site - this critical issue is still misunderstood. The myth that you cant add energy to the system after take off leads almost directly to young athletes being killed and injured.

[powerplant42]

The key is the definition of the word "energy"...

In some definitions, you could say "no" very truthfully.

In others, you could say "yes" very truthfully.

We should always say "yes" to young athletes that could misinterpret this.

Someone who knows phsyics better can explain the connections between the following terms: "system", "kinetic energy", "potential energy", "mechanical energy", "chemical energy".

[KirkB]

I think this thread got side-tracked with all the talk about "chemical energy" getting converted to "kinetic energy". If you put that aside, then we're only talking about adding "potential energy" to the pole and "kinetic energy" to the "system" (the pole + the vaulter) by muscular actions AFTER TAKEOFF.

Kirk

[powerplant42]

Well if you take away chemical energy, then you can only add potential energy (from horizontal kinetic energy in the run) in the pole's bend and in prestretching the anterior muscles. Then the potential energy gets reverted back into vertical kinetic energy which is, all the while, fighting the mechanical energy of the weight force acting on the vaulter. So really, no energy can be added if you totally ignore chemical energy.

Correct?

You can really only add (that is, "CREATE", NOT "get reverted") kinetic energy to the body in the vault (or in anything) by converting the body's chemical energy. This directly adds kinetic energy to the body, but not directly to the pole... it has to go THROUGH the body to get to the pole. So, energy gets added to different parts of the vaulter/pole system at different times and in different ways.

So yes, you CAN add (CREATE) energy after take-off... But ONLY by converting chemical energy ( this means that chemical energy must be left out of the definition of "energy"... otherwise, you can never add any energy to anything).

It's good that we get all this out there!

[KirkB]

Well if you take away chemical energy, then you can only add potential energy ... Correct?

No, that's incorrect, but I'm not going to let you suck me into a discussion of chemical energy transformation, as I've already said that that's irrevelant to the true purpose of this thread.

Energy can be added to the system in the form of both kinetic energy and (indirectly) potential energy. I think you only got the latter part of this.

If you want to discuss how SOME kinetic energy gets transformed into potential energy and SOME kinetic energy keeps the "system" moving towards the pit ... and DIRECTLY propels the vaulter skywards ... then I'm game for a discussion about that ... but I'm not going to lead it. Really, you should do some research about this topic to understand it better ... there's no sense in us just parroting all of the good research that's already been documented about this topic. I don't remember the scientific papers where it's discussed, but I think you can readily find them on the web ... there's several.

Kirk

[powerplant42]

Yeah I got a bit lost with myself. Potential energy isn't "added" (as in coming from nowhere), it is the result of a change from kinetic energy (moving) to potential energy (ready to "pop").

You never add chemical energy to the system, that's absurd. I don't want that to be what's coming across from my statements... Kinetic energy is added to the system through the body's motion, which is kinetic energy itself from the muscles (which are powered by chemical energy).

Here's the Linthorne paper... I think that's the one you're talking about.

http://people.brunel.ac.uk/~spstnpl/

Publications/PoleVault(Linthorne).pdf

(Copy and paste the two halves of the link, because it won't post it correctly.)

[kcvault]

To me, the analogy of a gymnast on a high-bar puts this question to rest. An athlete hanging in a static position beneath their hands can propel themselves to a handstand. They have obviously created energy. This means that the swing can create energy above what is present in the velocity of the run alone. Energy takes the path of least resistance, so some of that force goes into the moving pole, thus adding penetration.

I am with Tim this should put the question to rest. If you could not create energy from a swing then swinging giants from a hanging position would be impossible if it was true that the swing did not create energy then you should only be able to spin giants from a run. Also the ability to countinue to accelarate giants would be imposible if energy or force was not created from the swing. According to thermodynamics energy can not be created of destroyed but only transfered from one sorce to another. But this means what we eat we tranfer into energy that allows us to run, walk, and jump so in that aspect energy can not be created there is only the energy that was created by the sun. This however does not mean that more force canot be created from swinging, or pulling or pushing and other ways that you might manipulate the pole to roll to verticle. If you do not believe the example of the highbar watch a video of bubka the pole seriously accelerates as a result of Bubka swinging. There is not need to make this conplex trying to add laws of physics and other things, just look at video and see for your self.

---Kasey