namj
Junior Member
Posts: 88
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Post by namj on May 8, 2011 2:11:04 GMT -5
I do know whose hands have slowed down though, Shane Mosely's...lol. Sorry to all the Mosley fans bad night for them.
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Post by imperfectgolfer on May 8, 2011 9:08:01 GMT -5
Natep, You wrote-: "At Phil Cheetham's site: amm3d.com/ one can see on the homepage a kinematic sequence chart. The corresponding text states that the measurements of the hips and ribcage are rotational, but the arm and club speeds are angular swing speeds." --- "So, the following chart from Cheetham is measuring the angular swing speed of the arm and club (in degrees per second), and not the rotational speed of the arm and club around a particular axis, as Jeff stated." I am baffled by your comments - considering the fact that angular speed is synonymous with rotational speed. They are both measured in degrees/second and not mph. To measure angular speed in degrees per second there must be an axis of rotation. If you look at the torso/arm angular speed chart of the TPI researchers, the results are different to those measured by Chris Welch of Xenolink, and that's because they use a different axis of rotation in their measurements. Jeff.
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Post by natep on May 8, 2011 9:24:40 GMT -5
Yes, and Cheetham is measuring the swinging of the left arm from the left shoulder socket. And the left arm slows down before impact.
What I meant was that while the torso measurements are taken as the rotation around a longitudinal or vertical axis, the arm measurement is taken as the swinging of the arm from the shoulder in a near vertical plane.
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Post by imperfectgolfer on May 8, 2011 9:25:36 GMT -5
nimj, You wrote-: "If the endless belt concept is correct I don't see how you could keep a constant hand speed." You need to understand that the endless belt concept is only conceptual and it allows one to think of how the particular radius of a circular hand path affects the CF-release action. In a real golf swing the hand speed is not constant as the Rob Neal graph demonstrates. Hand speed increases throughout the mid-late downswing - while the club is releasing. That is a factor that must be considered. More importantly, there are two other factors that are going to affect the club release action. Consider Jamie Sadlowski's release action. Between 2 and 3 the major factor affecting the club release is the CF-release action - and it works according to the principle of the endless belt (even though hand speed is increasing between 2 and 3). However, between 3 and 4 the club continues to release. Two other factors affect the club release speed/efficiency at this stage - i) the right arm straightens and it applies a push-force at PP#3 which must affect the club release phenomenon and ii) parametric acceleration as the hands reach impact (note the hand arc path moves slightly upwards near point 4 and this applies a parametric acceleration to the club release - speeding the club up for a given hand speed). TGM concepts, like the endless belt concept, are conceptual and should not be taken too literally. They are merely helpful intellectual concepts that help us understand the principles involved in golf swing mechanics/biomechanics. Jeff.
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Post by imperfectgolfer on May 8, 2011 9:33:01 GMT -5
Natep,
You wrote-: "Yes, and Cheetham is measuring the swinging of the left arm from the left shoulder socket. And the left arm slows down before impact."
It only slows down if measured perpendicular to a particular axis of rotation. For example, if one measures the left arm's angular speed using a more horizontal axis of rotation, then the left arm's angular speed will slow down in the late downswing - because the left arm mainly moves along a vertical (downward) path at that time point in the downswing. If the left arm is moving very fast, but it is traveling at right angles to the particular axis of rotation used to measure its angular speed, then the angular speed readings are not going to reflect its true linear speed. That's the point Rob Neal was making in his article. His hand speed graph measured linear speed in mph and not angular speed in degrees/second.
Jeff.
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namj
Junior Member
Posts: 88
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Post by namj on May 8, 2011 11:34:53 GMT -5
Yeah, I still don't get the belt concept and how it relates to a golf swing. I think the "belt" can do lot's of things in space between the "pulley's" in a real swing.
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Post by imperfectgolfer on May 8, 2011 23:08:54 GMT -5
I am presenting these diagrams from Rob Neal's article because they clearly show that hand speed reaches its maximum angular speed at impact - even though left arm angular speed "appears" to reach its maximum speed before impact. Note that left arm speed reaches its maximum angular speed of 1161 degrees/second before impact, and the left hand reaches its maximum angular speed of 1871 degrees/second at impact. How is that possible if the left arm and left hand are part of an unitary structure? The reason relates to the angular axis of measurement. The green arrow represents the axis of angular measurement and it is normal to the plane of the left arm (sensor placed at the level of the left elbow) and left hand. Note that the left hand travels on a steeper plane and therefore measurement of its angular speed will give different angular speed measurements than left elbow speed, which is measured on a more horizontal plane. Rob Neal is not the only researcher who has demonstrated that the left hand reaches its maximum speed at impact. Nesbit also found that hand speed reaches its maximum velocity at impact. Jeff.
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Post by johnwalker on Nov 28, 2023 8:44:32 GMT -5
I think BM's golf forum cannot allow for paying single one. I didn't try before in this way just trying to move as best cavity back irons at that time and that's working fine.
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