Posted by: Teacherman () on Sat Oct 27 14:40:15 2007

Tom is right on target.

The shoulders resist rotation as the hips start their rotation. This is part of the separation process that leads to the "stretch and fire"...or...the instantaneous launch which results from the "unstretch".

A rubber band is worthless until stretched. It's value is in it's ability to "unstretch"...the elasticity. The hitter must employ this elasticity. Without it you simply have "brute strength rotation...or..."how fast can I turn"...versus the mechanical advantage gained by using the stretch/unstretch ability of the body. The highest level hitters stretch the upper body rearward against the opening of the lower body. This is all controlled by the hands/barrel. At the appropriate time the stretch is released and the bat is swung.

The shoulders do their very best not to rotate. IF they rotate they inhibit separation and therefore they inhibit stretch creation. The hips open against the shoulders....the hands turn the barrel rearward against the shoulders. The shoulders play a vital role by doing their best NOT to move. Of course they are attached to the hips and of course the hips eventually "win" so they will turn. But only because the release of the cusp. But to suggest shoulder rotation is powering the swing is completely inaccurate.

It's the hips and the hands that power the swing. The shoulders provide a platform for them to work agaisnt.