botakatobi wrote:You are correct that early vaulters did not try to bend the pole. Their focus was to swing very quickly and forcefully at a higher angle then todays vaulters.
Any bend their got from their wood, steel or glass poles was the result of their speed, grip height and pole rating. Yes, Gill rated poles from the early 1930's with the goal of pairing the correct size pole to the vaulter.
Coaches and vaulter did realize the whipping benefit of a flexible pole early on.
I think of a free take off as the vaulter being high on his or her toes while leaving the ground and pole tip hitting the planting box. Clearly this was not the goal or achieved by early vaulters.
What counts in a free takeoff is not when the pole hits the back of the box, but what the vaulter is doing with their posture and timing at the instant the pole takes the weight of the body. I stood ten feet from the runway and watched Bubka nearly set a world record taking off 8" under. He may not have been off the ground at the instant the pole began to load on all his jumps, but he attempted a free takeoff on all of them and the positive benefit of doing so was evident, even when the foot did not clear the ground. The differences in the arms between straight pole and flexible pole vaulters is entirely due to the fact that one bends and the other does not. I submit that Bubka, had he been forced to use a metal pole, would have had to change the alignment of his arms at takeoff, but little or nothing else to be able to compete with any of the athletes from the former era. Men like Steve Smith, for instance, or Dan Ripley would have simply been peeled off the pole. To compete on metal poles they would have had to change their entire approach to the vault, not just their arms. The video I referenced seems to me to be fairly conclusive. Yes the arms are different. But at the instant that the pole takes the weight of the body, the posture, attack angle, and timing are virtually identical.