Posted by: Mike Myers (mike.myers@bell.ca) on Thu Sep 16 13:34:03 2004

Jack,

I have been studying your general assertion that both legs contribute evenly to rotation around a stationary axis.

I disagree. The rear leg always supplies more power.

Reasoning is as follows:

Due to the relative position af arms and bat (to legs) throughout the swing, the body's center of mass, from intitiation to contact is always closer to the rear leg. One can demonstrate by comparing scale weight on both feet at various points in a good swing.

The body's axis of rotation is equidistant from both legs.

Torque = F x d (from axis of rotation).

Since the axis of rotation does not coincide with the (body + bat) center of mass, the rear leg must drive more mass, and maintain the same acceleration as the front leg. Thus, the rear leg must supply a greater force component than the front leg.

The fact that both legs exhibit rotational symmetry around a stationary axis of rotation, does not indicate both legs contribute equal torque, or power.

Regards,
Mike.