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Post by imperfectgolfer on Aug 29, 2013 10:57:44 GMT -5
See this Jeffy-forum thread. jeffygolf.com/showthread.php?775-What-s-wrong-with-this-pictureHe posted this animated gif image of Johnny Miller's swing. Jeffy then wrote-: " How does Dr. Kwon know "it is not true"? Certainly he can't tell from a single gif of four images taken from just one view??
To make such a claim as fact instead of opinion, wouldn't he had to have measured golfers with the "second fire" look of Miller and other elite golfers?" In what sense does JM have a "second-fire" look? I can only see a single continuous rotary/translational pelvic motion involving the left hip joint area, which is presumably part of the single continuous pelvic motion that actually starts at the transition. Also, see this other Jeffy-forum thread. jeffygolf.com/showthread.php?770-Geez-even-a-golf-television-commentator-can-see-itHe posted this you-tube video of Gary Woodland's swing. Jeffy again writes about a "second firing". Where is the "second firing" with respect to Gary Woodland? Is he referring to the rotary motion of the right pelvis, which happens post-impact, when he writes about a "second-firing"; or is he still referring to the motion of the left pelvis hip joint area? Jeff.
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Post by imperfectgolfer on Sept 1, 2013 21:34:20 GMT -5
Jeffy wrote- in his his forum thread-: "The first fire is by the spine engine and initiates the downswing, and the second fire are movements of the legs and hips which add power through shear forces."
How does "shear forces" create swing power? Why does Jeffy seemingly think that there are two different pelvic motions that require the terms "first" and "second"? Isn't Johnny Miller's left pelvis/left hip joint motion a single continuous motion that starts at the transition and that continues non-stop all the way to impact? Does the "second firing" of the pelvis not affect the spinal engine? If not, then how does it contribute to swing power?
Jeff.
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Post by imperfectgolfer on Sept 3, 2013 10:49:33 GMT -5
I am baffled by Jeffy's and Mike Duffey's thinking regarding pelvic motion - based on reading their posts in Jeffy's forum. I think that it is very easy to understand the pelvic motion in skilled golfers (amateur and professional). Consider Jamie Sadlowski as an example. Here are capture images - at the P4, P5, P6 and P7 positions. I have drawn a blue line over the lumbar spine area, which must mirror the rotation of the pelvic sacrum because there is very little independent rotation at each individual lumbar vertebra level. This represents what KM calls the "spine engine". Image 1 - end-backswing position - JS's lumbar vertebra are facing about 45 degrees to the right. Note that his left leg and therefore left hip joint is relatively unweighted, and it is therefore very easy for him to start his pelvic motion with a "left hip clearing action ala Hogan" where the left hip joint is pulled back towards the tush line in a rotary manner that causes the left thigh to rotate counterclockwise. This is not a "true" pelvic rotary motion - because I believe that the pelvis cannot really rotate because there is no no single pole of axial rotation. The pelvis simply moves in space and changes its orientation-in-space due to the biomechanical influence of the "left hip clearing action ala Hogan" phenomenon. By P5, the pelvis and lumbar spine is facing the ball-target line. If one imposes a rotary pelvic diagrammatic interpretation on this biomechanical phemonenon, one could state that the pelvis/lumbar spine has changed its orientation angle by ~45 degrees. One can see that his left thigh continues to rotate counterclockwise non-stop from P4 to P7, and one can see that the pelvis/lumbar spine orientation angle changes as a result of that single/continuous/non-stop "left hip clearing action" ala Hogan" phenomenon. Here is diagram showing where the front of the lumbar spine is facing at P4, P5, P6 and P7. It is obvious that the degree of change in pelvic/lumbar spine orientation angle between P6 and P7 is far less in magnitude than the amount that occurs between P4 and P5 and between P5 and P6. This doesn't mean that the counterclockwise rotation of the left thigh and adjacent left hip joint area is slowing down between P6 and P7 - but it does mean that the "effect" of the "left hip clearing action ala Hogan" on the degree of change in the pelvis/lumbar spine orientation angle is diminishing. It's a visually-incontrovertible fact that is easily discernible and I don't need a 3-D machine to discern that obvious fact. I also cannot understand why Jeffy/KM imposes the ideological concept of "first" and "second" pelvic firing on this simple-to-understand biomechanical process. I also cannot understand what it means when Jeffy talks about "shear forces" creating swing power when all I can see is a change in pelvic/lumbar spine orientation angle as a result of a non-stop/continuous "left hip clearing action ala Hogan" that is initiated at the transition. I also cannot understand how any golf biomechanist can believe that there is only a single power source (pelvis) which rotates the entire torso (including the upper torso) - via the kinetic link theory "belief" that there is a "fixed" amount of rotary energy that is inputted into the golfer's torso when he turns his pelvis at the start of the downswing and that this energy is transmitted sequentially from the pelvis to the upper torso and then to the arms via the COAM principle. It is very obvious to me that a golfer can power the rotation of the mid-upper torso independently of the pelvis due to the use of core torso muscles, and that different golfers manifest different degrees of dynamic torso-pelvic separation during their downswing due to variable amounts of energy produced by the "pelvic/lumbar spine" torque generator versus the "mid-upper torso" torque generator. In other words one could think of there being two torso torque generators. The power produced by the "pelvis-lumbar spine" torque generator obviously gets transmitted to the mid-upper torso via the spine and torso muscles/ligaments/soft tissues, but a golfer can also activate his "mid-upper torso" torque generator to produce additional power that can rotate the mid-upper torso. When I examine the "left hip clearing action ala Hogan" biomechnacal phenomenon in skilled amateur golfers, it is identical to that happening in what Jeffy/KM label "elite golfers". I think that it is a is fallacy to believe that elite PGA tour golfers are using a different biomechanical process than skilled amateur golfers. Jeff.
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