Posted by: Major Dan (markj89@charter.net) on Mon Jun 18 11:58:42 2001

lunging." Keep in mind that the arcing of the hand-path should not start until forward movement of the shoulders has stopped. Some batters with longer strides may have a 3 or 4 inch "back to center" drift of their hips. But their shoulder-axis does not drift forward but in fact it is more likely to fade in the opposite direction. I have noted hitters (such as Barry Bonds) whose shoulder-axis faded 2 or 3 inches away from the pitcher during rotation. But most good hitters rotate their hips and shoulders around a stationary.
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> > > > So Daniel, I agree with your observation that the hand-path is not a perfect circle. But the elongation you refer to is not caused from a forward drift of the axis. Rather, the back-forearm lowering from vertical to horizontal causes the elongation or added length. When the back-forearm is in the vertical position, the hands are at the armpit. But note how the hands extend (10 to 12 inches) as the forearm lowers.
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> > > > Does the "back to center" drift of the hips (or weight shift) add to rotation? Many coaches whose opinions I hold in high regard are convinced it does. --- I think it is highly overvalued.
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> > > > Jack Mankin
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> > > Jack-
> > > I believe the important thing is that Barry does fade his torso axis as part of applying bottom hand torque/hooking the hand path as he must on the inside pitches he prefers.
> >
> > Tom-
> > I've wondered about this as well. Maintaining a fixed axis of rotation is a far better model than moving the axis forward toward the ball (lunging or weight shifting during rotation).
> > What if the hitter realignments the axis of rotation by pulling the shoulders back or rippling a wave of energy up the spine - hips push forward, then as body rotates, the upper body also reacts back.
> > If timed properly, this would increase the tightening of the circular hand path at contact, adding extra batspeed into contact.
> > My image is that of rotation around the spine AND a wavelike motion of the spine (forward to back) running up the spine during rotation that feeds into release of bat into contact.
> > If this makes any sense (I'm finding it hard to explain) I'd enjoy yours and anyone else's comments.
>
> I think the axis has to "fade" back/?from spine-centered to more around back leg to hook handpath in front of body as needed on inside pitch.Pulling the hands in like a figure skater speeds up hip/body turn,but you are also hanging on to a big bat and need to keep balance.It is possible then that the axis isn't changing with respect to the center of mass,but only with respect to certain body parts.

Tom-
interesting suggestion - "It is possible then that the axis isn't changing with respect to the center of mass,but only with respect to certain body parts."
If you add in the bat itself, in addition to body parts, I'd agree more. If I try to throw a bat - swing and let go, make the bat fly out over the pitcher's mound as far as it can go ... I instinctively yank my shoulders/upper body back at release point. It seems to accelerate the bat. If you are right, the total 'amount' going back would equal that going forward from the center of mass of the body.
By conservation of momentum, the upper body is heavier than the bat. It moves back at X mph. The bat goes in the other direction with a speed inversely proportional to the difference in the weight of moved body and bat.
I hope this isn't voodoo science, just my attempt to make some sense of what I think is happening.