Posted by: Dave P (cdpaetkau@tleus.net) on Sun Jul 2 23:35:45 2006

> >>> If you watch closely you will see that the front hip does not rotate back as far as the front hip rotates back because if this was the absolute truth the body motion would be going backwards due to the tilt of the upper body during the swing. Therefor the bat would be decelerating due to the mass of the lower body puling backwards the the lower massed upper body going forwards. <<<
>
> Hi Dave
>
> If the axis of rotation is stationary (regardless of the angle of rearward tilt) and the body (hips, torso and shoulders) are rotating around that axis, I fail to see how you can say “body motion would be going backwards due to the tilt of the upper body during the swing.” There would be an equal amount of mass rotating forward around the axis as there would be mass rotating rearward.
>
> I will grant you that there are some batters whose back-hip does rotate more forward than the lead-hip rotates rearward. But I also have many clips of Bonds, Sosa and etc. where that is not the case. Their lead-hip rotates rearward at the same rate the back-hip rotates forward (axis, the spin).
>
> Jack Mankin

Hi Jack

I will give you an drill to measure and identify what I am trying to explain. First take a stride and have your front hip against a table and put an imaginary or drawn line down from the middle of your body on the floor (rotational point)and rotate so that your front hip comes back to that point. Now try to get our weight off your back foot (most major leaguers are seen with their back heel pointing to the sky and their back foot toes either completely off the ground or at least barely touching the ground prior to contact with the ball) while maintaining this rotation around that middle point.

You will SQUISH THE BUG with your back foot. This is not the action that you see in the top hitters.

Now instead of going backward to the middle with your spine rotate your back hip forward towards the table more then what the front hip goes back and you will replicate the heel to the sky and toes up senario.

Dave P

NOTE From SPORT SCIENCE by Peter Brancazio

If the line of force passes through the center of gravity, the force will only produce linear motion

IMHO Therefore the farther the center of gravity is away from the spine the more force that can be applied to create rotational forces.