Re: Re: Re: Re: RE: Change of direction - cont.
>>> I am not very good at thinking of the crack of the whip but maybe it is not in the hands but between the hips snapping and the shoulders then snatching around the crack coming from maximum stretch and then the snap of the shoulders into a rotational movement and a connected chp follows at the batspeed builds into contact. <<<
My view is very similar to your statement. I believe there is a ground up transfer of energy. I think of this upward transfer as the "kinetic chain" or the twisting of a rubber band. I do not consider it to be a whipping action. From the material I have read the cracking of the whip usually referred to how the linear acceleration of the hands transfer the body's linear and rotational momentum into bat speed as described in Adair's book.
I assume from what Teacherman and others are calling the crack of the whip, the shoulders are the handle and the whipping action propels the hands in a circular path. I have no problem with that concept. However, that is a far cry from the "crack of the whip" theory that had kids learning a linear hand-path by snapping a towel while extending and stopping the top-hand.
Note: I have not found that getting students to attain adequate hip and shoulder rotation to be their major problem. Developing transfer mechanics that turn shoulder rotation into bat speed is where their major problem lies. Below is a portion of an e-mail I recently sent on this topic.
Most batters develop ample hip and shoulder rotation during the swing. However, only a few have the transfer mechanics to keep the bat-head accelerating in sync with that body rotation. If the top-hand does not "create the correct resistance" (pulling back on the handle with the fingers), the bat-head's inertia will cause it to lag farther and farther behind shoulder rotation.
As the shoulders start to rotate, most hitters have the tendency to push forward with the palm of the top-hand. Pushing the top-hand forward on the handle does not cause the bat-head to accelerate rearward in sync with shoulder rotation. The batter winds up with the shoulders fully rotated, but the bat is lagging back 40 to 90 degrees from contact.
The first thing I look for while doing a video analysis of a student's swing is to see if the bat was brought to contact as shoulder rotation was depleted. This tells me how efficient their transfer mechanics are.
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