Apply angular momentum to gain elevation, by doing handsprings during the approach to the high jump. Basically taking advantage
There have been videos of soccers players doing a handspring on a in-bounds play and they can throw the ball much further than a conventional throw.
Gymnasts in the floor exercise get what appears to be incredible elevation dismounting after a tumbling routine.
When I was a kid, I was fascinated by spinning objects like tops. I would try to spin other things as well. sometimes the spinning object would be a little lobsided and start to fall over. When toppled over and hit an edge, the object would bounce.
My theory is that a spinning object that topples over will bounce off the surface. And gymnasts apparently get a lot of elevation at the end of tumbling run of handsprings and cartwheels.
Somebody needs to bone up on their Newtonian Physics.
No, it would not help. Period. When a jumper tries to get over a bar the goal is to raise his center of gravity over the height of the bar. When you flip your center of gravity does not change, your extremities simply rotate about it. Angular momentum is only really relevant with respect to the center of gravity, not to the ground. Any angular momentum gained from flipping is offset completely by the opposite momentum occurring on the other side of the center of gravity. In other words, flipping might speed up the rate at which your head rises but it equally increases the speed at which your feet fall, for a net effect of zero.