Could you explain what this means, and perhaps give an example or two of the types of exercises you mean?
This type of training is basically a precursor to the load/unload process that is part of swinging or throwing. The best hitters don’t load their hands and stop before starting their swing and the best pitchers don’t get their shoulders externally rotated and stop before they start their internal rotation. Obviously there is a very slight pause while changing directions, but IMO a quick turn around is the best way to get maximum “tip speed.”
The elastic energy produced as a result of this stretch enables the hitter or thrower to apply more force to the swing or pitch. Olympic lifts such as the power clean asks the body to produce the same type of stretch shortening action.
It is my belief that the quicker and more forcefully you can contract the larger and more proximal muscles in the swinging and throwing process, the more efficiently you will be able to apply force at the point of release or point of contact. The nervous system plays a huge role in this process. If you want to learn more about this concept, I suggest that you look at the material on www.inno-sport.net.