Posted by: Dave P () on Mon Sep 11 15:56:02 2006

> >>> 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. <<<
>
> Hi Tom
>
> I certainly have no problem with claiming the weight on the front foot increases to 125 % or more percent of body weight. But that does not mean it necessarily must come from a shift in the center of gravity. Granted, it could result from the momentum of the batter shifting his center of mass forward to the front foot during his stride. However, with many of the best hitters, there is no forward movement of mass as they prepare their axis for rotation. Therefore, there would be no forward momentum factor to account for the increase pressure on the front foot.
>
>
> It can be shown that a 125% increase of pressure on the front foot does occur without the batter transferring any mass forward. An increase in pressure on the front foot is induced as the batter’s flexed lead-leg is extended – similar to the way pressure on the floor increases above your body weight as you jump straight up.
>
> Jack Mankin

Jack

How did you test the forward momentum of the mass of the hitter? If you look at the biomechanics of dropping your front heel to swing (no one swings flat footed) the mass of the body must move forward towards the front leg because if it does not then you have come to a static position. You can not move fast from a static position.

Please answer the first question because while I was in university we did test for this but not with hitters but with other movements. It was not something that you could just look at a video and determine.

Dave P