slight sinking after swing is initiated

[fishman4god]

I have been reveiwing film and have come across what appears to be a somewhat odd (at least to me) differentiation in technical execution of vaulting. In some athletes (advanced: over 15' men and 13' women) there sems to be a slight sinking that occurs (com) after the swing and before they give the left arm. On other athletes (same general level) there is not a sinking (com) but a continual upward/or flat moment (of com) in some cases before they give the left arm. Some vaulters seem to give the left arm imediately but others there is a longer delay. I am thinking the longer delay is the culprit and yet the outcome (generally is the same) ie. a successful well executed vault. I have seen it throught the elite level and am trying to determine what the root cause would be and ultimately does it really meatter that much if the other areas are well executed. Just curious really (yes I am sure you have seen this too) Just want to know if there is a diverse number of explanations/answers or if it is just the left arm being straigtened after the swing?

[Tim McMichael]

There are lots of factors here, pole design and grip height being some of them, but in general, the vaulters who do not flatten out during the middle of the jump and keep rising toward the bar have more efficient jumps. The pole sits solid in the corner of the box and the pole releases toward the crossbar the instant it finishes bending. This gives the jump more pole speed and a wider top end. The larger question is why this happens for some and not for others and I think the answer would require an entire book. The broad principles involve efficiency at takeoff and finishing the swing at the right time, which are related. In my analysis, athletes who are still swinging after the pole has reached maximum bend tend to flatten out or even sink a little.

[fishman4god]

I tend to agree. I have noticed that vaulters of a shorter stature seem to sink/bend the pole more (Lavillenie as an example). Pole size /weight aside and takeoff mechanics being somewhat equal do you think that stature could be an underlying factor?