Posted by: Jack Mankin (Mrbatspeed@aol.com) on Tue Apr 29 01:37:52 2003

>>> I'm talking about a swing clip I have of Arod where he is clearly fooled by the pitch. Body is going left, hands are going right. He is totally broken down. There was no tht in the swing, and the hand path is straight as he "throws the hands at the ball".

Are you avoiding the word "whip". <<<

Hi Teacherman

Below is an old post regarding Professor Adair and his “whip theory.”

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Professor Adair (author: “The Physics of Baseball”) does not believe the balance of the bat speed is generated from torque. In fact, Adair does not believe torque is a factor at all in developing bat speed. He stated in his book, and to me, that any force applied by the hands to the handle of the bat would have a negligible effect on the bat head.

Professor Adair believes (as outlined in his book) that the arc in the path of the hands accelerates the bat to about 40 mph. That it is the release of kinetic energy (whip effect) that accounts for the bat’s acceleration from 40 to 70+ mph. In his model of the swing, the body’s center of mass MUST move forward 12 to 18 inches at 6 to 8 mph DURING the swing. Then, as the forward progression of the body and hands slows to a near stop, the body’s kinetic energy is transferred by the whip effect and accelerates the bat-head.

I wrote to Professor Adair that a frame-by-frame video analysis showed that although the batter may take a stride in preparation for the swing, the forward body progression cames to a stop before rotation and forward movement of the hands started. That the batter then rotated around a stationary axis and there was no further forward movement of body mass during the swing.

Professor Adair wrote back that what I proposed was impossible. That without forward movement during the swing there would be no energy to transfer. He ended his letter with this quote; “I found your essay on batting quite unpersuasive even as it was non-quantitative. And any batter who would use your “stationary axis” model, taken literally, could not hit a ball past second base.”

I then mailed Professor Adair a video with a number on frame-by-frame clips showing many of the best hitters rotating around a stationary axis. (In 1988, I had one of the few VCR’s that could freeze a frame.) He could now clearly see that there was no forward movement of body mass during the swing. During a pursuing phone conversation he really seemed puzzled and stated that he may make some changes to his second edition of “The Physics of Baseball” he was about to publish.--- There were no changes I could note in his writing or swing model.

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Teacherman, at least Adair concedes that about half of the bat speed comes from an arc in the hand-path. You do not believe that torque or a chp is a necessary factor . I see no basis for further discussion while you believe that the “whip effect” accounts for all the bat speed Arod generates in any clip you may have.

Jack Mankin