Decamouse wrote:"Here F(tens) is the force on the pole, and one can see its greatest at the perpendicular to the ground and grows smaller as the swing progresses" - true statement if the brick wall (top hand grip location on the pole) is fixed (which it is not - since it moves upward and toward the pit - with both the x and y change rates varying to almost all y (vertical) at end of vault
The other part is the rotating COM does exert a force based on the speed it rotates and if that changes so does the F(tens) -- also the distance of the COM is from the brick wall (pt A) changes -- if we call the shoulder rotation point B and COM the COM - A-B distance remains fairly constant - B-COM distance does change and changes more in RL than SB - so yes gravity is always present - does the takeoff - swing - and how the vaulter varies the B-COM distance matter - yes and some of that is based on the skill level and physical abilities - now which variance will work best for a given vaulter -
The point is to clear the highest set bar - that also mean doing all these things as close to your optimum and being on the correct pole, with correct standard placement when the bar is set at the WR height - big clearance at the height below does not count for the record (might actual give you what the optimum potential and hence point towards technique)
One thing is constant - gravity (ok we can get real anal - it does vary the further you get away from the mass that is responsible for the gravitational field)
While "gravity vector" is a way to look at certain parts of the vault -- all of this matter not if it can not be related to the vaulter in the coach vaulter interaction and based on their physical skills sets and capability - vault high - different perspective are good
One thing that I've always said is that this sort of analysis gets very very complicated very fast. It's the nature of this system, of vaulter and flexible pole. Still, the relationship to gravity and the swing angle are relative and changing and I contend a very important consideration. The whole of the event is set against gravity and so one idea seemingly has been not to think about it very much. The other tack which I take is to think about it front and center.
But this view I take also harkens back to the PB and the idea not to have the hips thrown forward. It is an explanation of things and explains why that was such a good idea and a paradigm shift and revolution when it occurred. I contend it was the most important and least understood idea of the model. And that Lavillenie is the proof of what taking this idea to its logical extreme can accomplish.
It also helps explain why vaults fail.
1) Taking off under and leaning back - The vaulter enters in "swing progressed" so from the start they are losing compressive value from the pole because of the CoM relation to gravity. The chord shortens less and slower and so the pole rotates less. Vault suffers or fails
2) Raising the trail leg - Raises the CoM and shortens the lever causing the vaulter to rotate forward faster again causing swing progression and a loss of force on the pole compression moment. Same result.
3) Vaulter throws hips forward and/or tilts head back - Again, throws the CoM forward in time into swing progression again with loss of compression. Same result. I have a vaulter with an excellent plant. You freeze his plant and he looks fabulous. But at the moment of plant he has intention to thrown the hips forward and head back while also raising the trail leg. So he shoots forward in swing angle. And you can just watch the pole not respond. I say this from watching him be better and worse at all of these things.
These are common problems that every decent coach knows are problems. I haven't done anything to "identify" them as new or revolutionary problems. What I have done added a new* physics explanation as a component of the reason why. Then I've taken it to its logical end with the appearance of Lavillenie. This is how he vaults. He works to maximize his relation to gravity in relation to the pole. Is he conscious of this? Is his coach? Heck if I know! It could very well be that it came intuitively and/or through trial and error. Such are things with this event.
*I say this only in so much as it seems completely foreign to the readers of this site