Posted by: Jack Mankin (MrBatspeed@aol.com) on Tue Dec 7 13:51:43 2004

Hi All

I have received numerous e-mails from BatSpeed.com readers who are concerned with claims from another site that say although CHP, THT and BHT are helpful cues, there is no scientific basis for them. They claim that Adair’s book (The Physics of Baseball) describing the “Crack of a Whip” theory is the correct science.

However, their claim could not be farther from the truth. I took findings from my video analysis study of thousands of major league swings to three different Southern California Physics Labs. I consulted with these Professors to define the scientific principles that induced the angular bat displacements shown in frame-by-frame segments of the swing.

After many tests, all three Labs concluded that there were two physics principles that govern the angular displacement rate of the bat. (1) Mass tends to stay tangent to the direction of force (CHP). (2) Vectored forces applied at the handle from opposing directions that cause an object to rotate about a point (Torque).

I then used these principles to define the Rotational Transfer Mechanics model. Since the principles of this model differed substantially from the principles outlined in Adair’s book, I decided to send him a 25-page paper describing the rotational model. His reply was sarcastically negative (I still have his letter).

Example: Adair states in his book that in order to develop energy that accelerates the bat, the body must move forward “about 18 inches at 7mph” during the swing. I pointed out to him that with my rotational model, the batter may stride forward as he sets up the launch position, but the batter actually rotates around a stationary axis during the swing. – His letter replied, “And any batter who would use your “stationary axis” model, taken literally, could not hit a ball past second base.”

Rather than the three labs that assisted me in defining my rotational model, I decided to ask a qualified unbiased outside source to evaluate the scientific correctness of the two models. After a couple weeks of consultation, Professor Harvey S. Left, Chair Physics Department at Pomona, California College of Science agreed to give his evaluation.

I took a copy of Adair’s book, his letter to me and my work to Professor Left. A month or so later he mailed his evaluation to me. Although due to professional courtesy, he did not mention Professor Adair by name, it is obvious as to whom he was referring in the last paragraph. Below is a copy of Professor Left’s letter.


14 December 1991


3801 West Temple Avenue
Pomona, California 91768-4031
Telephone (714) 869-4014
Physics
College of Science


To whom it may concern:

I have had the opportunity to view a 100-minute video tape by Jack Mankin, summarizing his findings on the mechanics of baseball batting. I have also read some of his writings on this subject and have spoken with him on several occasions. Jack Mankin has spent an enormous number of hours analyzing professional batters, using frame-by-frame observations (at 1/30 second time intervals). He has painstakingly developed a clever categorization scheme containing dozens of batting characteristics. Of these, he has identified a handful of the most important batting elements. Although he is not a scientist, Jack Mankin has designed and followed a thoughtful, careful, objective, science-like approach that is very impressive.

Batting entails a good deal of rather complex physics. To my knowledge, the research that has been carried out in the scientific community lags behind Jack Mankin's path breaking work.

Sincerely,
Harvey S. Leff, Chair Physics Department
##

Countless times I have asked dissenters from the other site “if they disavow these scientific principles my model is based on.” -- (1) Mass tends to stay tangent to the direction of force (CHP). Vectored forces applied from opposing directions that cause an object to rotate about a point (Torque). In every case, invariably their response is to sidestep the answer by asking additional questions. – However, I understand how anything affirmative could put them in jeopardy at their home port.

Jack Mankin