Bouncing on the Saddle.
No doubt it can be agreed upon that lower extremity neuromuscular coordination contributes towards driving the crankarm in a circle. But there are limitations.
If you take a closer look, you might find a low grade bounce. If you returned to that same event 5 years from now, the same folks would be bouncing on the saddle under similar circumstances, 5 years of racing under their belt. This is not from lack of training or effort by any means. I recall, some years ago now, observing an athlete who was engaged in an acceleration (at the track), shift off the saddle, applied effort on the downstroke propelling the body up, in no small manner, up and down, and unable to accelerate at all.
So we are faced with the problem of instability.