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.
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...
You were simply interpreting that graph which showed that arm speed was not much greater than shoulder speed and that arm speed peaked soon after shoulder speed.
Just as cameras produce artifacts, so do the golf researchers. They confuse us with different graphs. That graph represents the view of "reality" as produced by the TPI researchers. Here is a graph produced by the Welch-Zenolink researchers, and this graph represents their view of "reality" regarding the kinetic sequence.
The blue curve represents the shoulder speed, and the green curve shows the arm speed. One can see that the arms travel much faster than the shoulders after the shoulders decelerate and that the arm speed peaks much later.
This post is traveling in the wrong direction when the baseball swing is used as an example to make a point. Notice that Englishby uses a T and not a real pitch from 60' coming at different speeds and on multiple planes. If you want to actually compare with baseball, check out Manny Rameriz, Ken Griffy Jr, Aaron, Bonds or Babe Ruth to see how players develope momentum and bat speed through the hitting area. Most ball players can hit a golfball with authority but also need radar to find some of their shots. A tournament golfer is a different animal. Please be careful when teaching young players. Get back to G.O.L.F.
The long drive guys need to hit high like the baseball players. There are some distinctions between Zuback's move and the classic reverse C. First, Zuback's legs are straight instead of still bent and way forward. Second, his head goes back because he thrusts with his core so much not because he just hangs back. I'm not saying his move is easy on the back, but it is not the same as the 70's reverse C. I've tried it. It is very powerful, but it can lead to spraying the ball.
Thanks HB
Thats a great observation that will help any readers who are going out there to try the tilted, long ball. I remember my 70's swing had a good deal of double anchor and back pain associated with it.
Im really interested in this elevation, extension thing through the shot. I notice a lot of great golfers doing it and my results have been very good with it. For me its real down then up feeling. The camera doesnt show too much head movement, however in the down direction. I like it but how do we separate this from bobbing? (assuming you subscribe to a little down before the up, maybe not)
How about the authors "twist" as in "jump and twist" the ice skaters jump analogy.
Thats a great observation that will help any readers who are going out there to try the tilted, long ball. I remember my 70's swing had a good deal of double anchor and back pain associated with it.
Im really interested in this elevation, extension thing through the shot. I notice a lot of great golfers doing it and my results have been very good with it. For me its real down then up feeling. The camera doesnt show too much head movement, however in the down direction. I like it but how do we separate this from bobbing? (assuming you subscribe to a little down before the up, maybe not)
How about the authors "twist" as in "jump and twist" the ice skaters jump analogy.
Thanks for this, very interesting
O.B.
I like the jump and twist analogy. Tiger bobs but I never see him hit fat. I think you can do these moves without bobbing. I think you can do a nice amount of thrusting without having your head go back at the end (ie less than Zuback). Look at the knees. Bent in delivery....straight in follow through. Loading into the ground like you were trying to hit low (blow up the plane line). Then, without disturbing the power package, using your legs to get the club out of the ground.
I like the jump and twist analogy. Tiger bobs but I never see him hit fat. I think you can do these moves without bobbing. I think you can do a nice amount of thrusting without having your head go back at the end (ie less than Zuback). Look at the knees. Bent in delivery....straight in follow through. Loading into the ground like you were trying to hit low (blow up the plane line). Then, without disturbing the power package, using your legs to get the club out of the ground.
If the right hip is held back in transition and the hips slide forward a la Hogan, V.J. Trolio etc., is it the right hip that does the twisting? Homer assigned so many things to the right side all most as if it was his first choice unless he found out otherwise. This is sort of what I was wondering about in regard to the suggestion that he "he ran his right leg at the ball" it maybe being more of a hip or right hip action.. I dunno. Im really trying to figure it out for me not Hogan but I can sort of see/feel the twist being a right hip action with a corresponding active straightening (but not too full extension) of the left leg. I have a feeling Yoda might call this a hip action too.
How do you see the hip twist, given a held back right hip and the weight left?
I personally think that there is an advantage to flexing the knees like Hogan in the downswing.
When one swings the club down-and-out-and-forwards in the golf swing, one of the three-dimensional forces is a distinct downward force. I think that it's likely that a golfer can better stay in balance - while maintaining all his body/spine angles and while avoiding tippling forward - if he initiates a marked downward thrust force of the club in conjunction with a piston-like flexing of the knees. It is like a downhill skier going through a mogul run - they flex their knees like crazy in order to keep their upper body stable. A golfer wants to keep in balance and keep all his body angles intact during the downswing, and if the golfer has a very forceful down thrust action (like Tiger Woods) then using the knees as shock-absorbers/stabilisers may be biomechanically advantageous. I do not generate sufficient downward thrust to require that type of knee action, but golfers like Tiger Woods and Jamie Sadlowski may benefit by using that type of knee-flex action.
Thanks Jeff, most of the compression occurs during the backswing in that sequence. A little bit more occurs in transition but head height is very still during release...very big pivot driven release...new edit waiting for upload...
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