Posted by: tom.guerry (tom.guerry@kp.org) on Mon Sep 11 10:17:37 2006

Very interesting thread and comments. Thanks Jack and all.

With respect to weight shift and rotation, I would say that what is usually "seen" at a more basic level from various sources including video, motionanalysis (zig and others) and pressure plate studies (Yeager),is that the center of gravity goes forward and down,then stops its forward progress and goes up a little. PRessure increases on front foot up to about 125% or more of body weight. Location of weight bearing area of feet with regard to position of center is important, as is position of head with respect to center.

Coil/separation/"winding the rubber band" starts before or at front toe touch as the center of gravity is lowering/going forward.

The redirectrion of the center of gravity is then associated with a last quick stretch/separation between the shoulders and hips.

The "UP" is associated with unloading/muscle shortening.

Perhaps more important than "hips leading" or sequence of separation is the overall body "posture" or tone (creates a structure to support the desired rate of stretch as well as orientation of swing plane) that includes synchronization/coordination of upper and lower body movements such as THT and front leg action - "turn bathead/turn front foot", realizing that upper body runs the show.

The "theory" behind xfactor stretch/cusp is that this reversal of loading or unloading is the most efficient way of accelerating the bathead using momentum. It depends initially on elastic and other soft tissue properties followed by the increasing contribution of force production by muscular shortening.

This is quicker than excessive dependence on "muscling" the swing.