Rick,
So I guess my question is do you think pitchers are deliberating trying to snap their hips in that way? Or do their hips snap as a matter of making more powerful and deliberate movements elsewhere?
Compare it to the whipping action of younger, weaker pitchers v. elite pitchers. The latter tend to have much shorter and more violent arm whips, which I'm sure is deliberate. That action could cause other things to change from the actions of the former. It's not that they're trying to do those things, they just occur because of the energy level being applied.
What I would argue/wonder is whether it's something you teach, or is it merely something you look for to confirm that the body is being used properly? Did Sarah have to learn to do that and work on it, or did she just start doing it as she got bigger/stronger/better?
Ken
How about this answer--Both. I think the hip snap is a natural athletic move that the body instinctively does. People that don't have this natural athletisism can develop a hip snap----Sarah did. Lots of work throwing from the "slingshot motion" and emphasizing a hip snap will help.
Yes, I think you should incorporate the hip rotation/snap into your warm-up drills from the very beginning of teaching a pitcher. It is very difficult to impossible to get the body to do this later.
I do like lhowsers rubber band description and Marks transfer or energy description. This is what I percieve as happening. Focusing on the core muscle groups to create hip snap works best for my teaching.