Originally Posted by Jeff
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OB Left
GBD
You wrote-: "I am not convinced that the arm rotational velocity increase much between green diamond and blue circle (time point for max arm speed)... the arm speed trace seems to plateau at about the same time as the shoulder rotation...approximately."
I am surprised that you harbor that belief. I have always believed that one needs to release PA#4 efficiently so that the arms swing freely across the body into impact. John Jacobs in his book "Practical Golf" strongly emphazises a free flowing arm swing. The arms should not outrace the torso, but they definitely shouldn't only travel as fast as the torso rotates. The arms should surely travel faster than the upper torso in the late downswing.
Jeff.
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Jeff, with reference to the paper that you quoted - the peak rotational velocity for the arm and thorax appear at approximately the same time point - green diamond and blue circle. So it is not so much my belief...rather my interpretation of that data....arm velocity is greater than thorax velocity but the peak velocity of each appears to coincide.
Seems to me that acceleration of arm is dependent on thorax in THAT swing. You can use TGM concepts to interpret this golfers data...but you can not use this golfers data to prove or disprove the validity of TGM...however expert he may be. Homer said that even the best pros do not always do it as well as they might...or something to that effect...so studying their photos to prove / disprove TGM does not work.
My interpretation of TGM is that the pivot carries an "arm swing" until release of acc 4 then the pivot moves to support alignment of the power package in accordance with plane line etc... again, not a belief - just an interpretation of the literature. Once acc 4 is released a free arm swing will have no further rotational acceleration but should maintain approx. constant velocity until release of acc. 2,3. My interpretation of the book. I ca sleep at night if its incorrect though...
