Posted by: Jack Mankin (MrBatspeed@aol.com) on Fri Dec 14 20:48:10 2007

Hi All

I will soon start a thread to discuss whether or not a batter�s linear momentum developed during his stride is a factor in generating hip and shoulder rotation. For this discussion, we need to clarify the difference between the term "weight shift" and "momentum."

I think we can all agree that since the batter's axis is tilted rearward, he has more weight on the back-foot as he initiates his swing. We can further agree that during the swing, the batter's weight on his back-foot becomes increasingly lighter so that by contact almost all of his weight is supported by the front-leg. -- Therefore, many would say that during the swing, there is a "back-to-front," or forward weight shift.

However, was there actually a forward shifting of weight (linear mass movement) that would develop momentum (mass x velocity) to do work. As an example, what about a batter who does not take a forward stride but just initiates rotation about a stationary axis. He would also start with most of his weight on his back-foot and finish with his weight on his front-foot. But, since his body (or center of mass) attained no linear velocity, there would be no momentum to do work being generated.

I know this is probably "information overload" to many of you. I do feel however that it is necessary to make this destination between the term "forward weight shift" and the actual generation of momentum for our coming discussion.

Jack Mankin