Pole Vault Manifesto

[altius]

Volteur old son you stated - "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". If you had added, "until the pole contacts the box", I would have had no problem. But left as it was, this sentence might tend to reinforce the notion that many folk do have, that the vaulter cannot add energy to the vaulter/pole system once they leave the ground.

This idea is dangerous because it leads to a 'cannon' theory of pole vaulting and - if you go back and read the posts on pvp over the past three years -in turn this leads folk to believe that THE critical factor in vault performance is run up speed. My observation of vaulters in Reno ten years ago - reinforced since on many occasions - is that this myth is likely to lead to accidents of the kind we saw in the US a few years ago. Rightly or wrongly I have tried to debunk this myth and have suggested that vaulters and their coaches would be better off accepting agapits continuous chain model of energy input.

In an attempt to make that notion more approachable to inexperienced coaches I suggested the idea of a four stage rocket in which energy is put into the system in four distinct phases - which can be linked to specific elements of Bubkas technique. With experienced athletes a three stage version is more appropriate. Of course all the time being aware that it is a continuous flow. All of this is detailed in BTB2 for folk to accept or not.

So my response to your comment must be seen in the light of some history - that you might not be aware of as a new arrival on PVP.
Another part of that history is to continually see newcomers like yourself address these issues as if they had never been discussed before - hence the unwarranted sarcasm for which I apologise.

[volteur]

Dear Altius,

i would like to engage you in a debate on the pre-jump. I'm not intersted in what has gone before i'm really only interested in what we can come up with from now on. I'm quite an experienced vaulter and also quite experienced with human movement mechanics which i think tie in very well together.

Possibly i don't understand precisely what you mean by a pre-jump so could you help me with a definition please. What i do understand is that there is a small period of time between leaving the ground at takeoff and having one's weight load against the pole. It is this small frame of time that i think is not in line with what i understand of mechanics and energy flow. It is like a break in the continuity of the chain model. Can you correct me on this or not?

I do have some understanding of what Petrov means by a free takeoff. He himself has shown me this and he spent a long time showing my coach. From what i understand and have practised the loading onto the pole begins to occur as the takeoff foot is still on the ground. We will have to spend some time on this issue i think.

I spent a good year attempting to take off further and further out from the position where my hand is above my foot. As a 10.60 and 7.70 type of athlete i could actually increase this to 1.5 feet lengths off 10 strides. Now my pr off 10 strides is 5.10 and by the time we were 1.5 feet back i could barely jump 4.60. The conclusion in the end was simple, it just took us a year to make it. The further i took off out from this hand under foot position, the more entropy the system undertook. Less and less continuity from plant into rockback. As i started to bring the foot forward towards the 'ideal' position things began to return to normal. I could once again have continuous motion from takeoff into rockback.

Again possibly i am confused about the definition of a pre-jump.

cheers

Volteur

[volteur]

Hi Aerovault.

I like your thinking. The idea that the potential energy one has when descending from the takeoff is a good one. This potential energy then assists the vaulter in loading the pole during rockback does it not? I can imagine the vaulter descending as the pole continues to bend and then due to the rotation of the rockback they can then be flicked off the top of the pole as it straightens.

So i'm thinking we all want the optimal amount of potential energy at this point. How is this optimal situation created? By correctly combining the two variables in action on the vaulter at takeoff. They would be in my mind vertical lift and horizontal velocity. Correctly combining the two would result in the optimal potential energy. So how much vertical and how much horizontal? These two axis serve to create a line we travel along as we initially takeoff. What is the angle between this line and the ground? The takeoff angle for pole vault.

cheers

Volteur

[altius]

Sorry Volteur -this is one of the issues which has been dealt with several times in the past - and clearly has not been resolved. I can only suggest you borrow a copy of BTB2 from someone and take a look at pages 242 and 243 - everything I know about the pre jump is there. In essence it describes how Bubka made it clear that this is what he attempted to do at take off - but that it was very difficult and that he was only able to do it a few times in his career.

Note that pre jump is a term I coined in 1989 to define the nature of Bubkas take off as it was explained to me by Petrov in Canberra in 86. Petrov does not use the term - nor does Bubka - however I believe it is what he described in Jamaica where he indicated that he wanted to be in the air - and I quote "we can say no more than hundredths of a second, going from the end of the take off and the moment in which the tip of the pole reaches the end of the box. But this short time makes a big difference that allows the competitor to greatly improve their results."

Anyway as indicated above I have done my best to explain it previously on PVP and in BTB2 and do not want to revisit it again - i am sure you can get plenty of discussion going with other folk.

[volteur]

thanks Altius i think you explained everything with the 'less than 100th of a second' statement. This means at the beginning of simultaneous to me. Just ahead of the moment one meets the pole and not after that moment or it would be called a late plant. The idea that this gap being anything more than 'just' prior seems to be as if it doesn't actually work.

If that area is done with then can we talk about the very next? What happens as the pole beings to bend. Is there a period of time which is virtually 'resistless' as the pole begins to bend. The pole is after all easier to bend a little bit than a lot.

cheers

Volteur

[AeroVault]

Volteur,
I assumed by your number of posts that you had less vaulting and mechanics background than you do. My mistake. I think there's still a bit of a misunderstanding, however.

The idea that the potential energy one has when descending from the takeoff is a good one. This potential energy then assists the vaulter in loading the pole during rockback does it not?

This was not really my intention, as the vaulter should never descend after leaving the ground. With the free takeoff or prejump, I try to use that potential for height only, not to convert back to stored energy in the pole. It is like taking whatever bar you cleared and adding a couple inches to it. As I said before, the swing starts with the pole tip hitting the back of the box, so from that point everything works the same whether you're on the ground or off of it. It is advantageous to be higher up mostly because of the better angle of the pole. The added potential energy is just useful because it's not lost energy and contributes to your final height.

[volteur]

Hi,

thanks for replying. I guess using the word descending on it's own was my mistake. It doesn't fully reflect how i see it. It could be better described as an invisible downward motion that occurs whilst one continually lifts through the vault. It exists in that portion of the jump where the acceleration slows and i guess the rockback occurs whilst it is happening. The vault is up at takeoff, down at rockback, up at clearance and down to the landing. I don't think of it as one giant up all the way to clearance.

Just on the other point of increasing the pole angle. Do you see this as the higher the better, or is there an optimal angle?

[AeroVault]

That's a good question. My gut says the higher the angle, the better. Only caveat is that you need time to swing to inversion before the pole reaches vertical. The optimal angle seems to depend primarily on speed and grip height.

Assuming an ideal swing, if the angle is too high and the pole is moving too fast, then you'd want to move your grip up which effectively lowers the angle back down again. Then you'd try to increase your speed and pole angle until the pole moves too fast with that new grip, and so forth.

I know DJ's mid mark chart compiled data for speed and grip height necessary to clear each bar assuming an 8' reach on takeoff. You might want to use that chart to calculate some pole angle numbers. If you have a higher reach (higher angle) you could still rotate the pole to vertical without as much speed. Tall vaulters definitely have an advantage.

[agapit]

Hi,

thanks for replying. I guess using the word descending on it's own was my mistake. It doesn't fully reflect how i see it. It could be better described as an invisible downward motion that occurs whilst one continually lifts through the vault. It exists in that portion of the jump where the acceleration slows and i guess the rockback occurs whilst it is happening. The vault is up at takeoff, down at rockback, up at clearance and down to the landing. I don't think of it as one giant up all the way to clearance.

Just on the other point of increasing the pole angle. Do you see this as the higher the better, or is there an optimal angle?

You really should think of the vault as a giant UP all the way to clearance. The most important component determining the height of the clearance is a vertical speed or the center of gravity. If your mental picture is “downâ€

[AeroVault]

I had used the term "takeoff angle" when I was referring to "pole angle". Edited above post for clarification

[altius]

If you want to learn more from agapit you can always attend the coaches clinic to be held at Slippery Rock June 13 - 15.

[vault3rb0y]

Altius has said before that in order to get serious benefit from a pre-jump, you must be incredibiy athletic AND technically sound. The whole point is to be at a higher angle to the box when the pole tip hits the back, which is when the continuous chain actually starts, not when you leave the ground. So, in order to benefit from it, you must jump at a high enough angle to be 2-3 inches taller when the pole hits the back, WITHOUT sacrificing speed to jump at this angle. That angle means nothing if you kill your pole speed to do so. Being in the air that split second longer also lets you set up your swing better, so when the tip does hit the back you aren't sacrificing time to extend your trail leg, or "drive" into the vault before swinging. In theory it works great, and the mindset should be there in the vault, but until your run is at its highest level, i wouldn't worry if we arent 3 inches outside from a free take off.