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Post by imperfectgolfer on May 26, 2020 8:49:44 GMT -5
DG,
You asked-: "If Rory's torso is rotating faster than his left arm , then doesn't that mean his left arm is 'lagging behind' from P4-P5 (even though PA#4 is being supposedly released by the pivot)?"
I don't see any left arm lagging in Rory's downswing action between P4 and P5 - his left arm is in the correct positions at P4.5 and P5 - even though his upper torso has more angular distance to cover during that same time period due to his large degree of upper torso rotation at P4.
Jeff.
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Post by dubiousgolfer on May 26, 2020 9:05:47 GMT -5
Many thanks Dr Mann
DG
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Post by utahgolfer on May 26, 2020 9:45:01 GMT -5
My paradigm has always been to let the pivot bring my left arm down. There has been very little sliding of my left arm down the chest from p4 to p5. I have some dissociation hula hula but very little when my left arm is strictly pivot driven. I have never wanted to be an arm swinger due to my pivot paradigm. But, with a short backswing, I need to follow Rahm’s example. If I turn my hips fast I have decent hula hula separation. If I swing my left arm down my chest independently at the same time, it helps my hula hula. This may help me reach a peak left arm speed sooner in the downswing.
I don’t mean to bore you with my paradigm shift story, but there is definitely more than one type of golfing machine on the PGA tour.
UG
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Post by imperfectgolfer on May 26, 2020 10:07:45 GMT -5
My paradigm has always been to let the pivot bring my left arm down. There has been very little sliding of my left arm down the chest from p4 to p5. I have some dissociation hula hula but very little when my left arm is strictly pivot driven. I have never wanted to be an arm swinger due to my pivot paradigm. But, with a short backswing, I need to follow Rahm’s example. If I turn my hips fast I have decent hula hula separation. If I swing my left arm down my chest independently at the same time, it helps my hula hula. This may help me reach a peak left arm speed sooner in the downswing.I don’t mean to bore you with my paradigm shift story, but there is definitely more than one type of golfing machine on the PGA tour. UG I do not think that it is an advantage to reach peak left arm speed sooner, and peak arm speed should its maximum value at ~P5.5.To generate a greater clubhead speed at impact, the speed of release of PA#4 must be faster overall, but the peak left arm speed must not happen sooner than P5.5. Also, it will not work to move the left arm faster if one cannot also speed up the pivot action because the pelvis must become slightly open at P5.5, with the upper torso slightly closed at P5.5, so that the pivot motion perfectly matches the left arm motion. I personally have an ability to pull my left arm downwards faster if I choose to pull it down faster, but I cannot speed up my pivot motion to match the faster left arm motion, so I am therefore forced to slow down my potential left arm motion to ensure optimum coordination between the pivot motion and the left arm motion.
Jeff.
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Post by dubiousgolfer on May 26, 2020 10:19:22 GMT -5
Dr Mann/UG /S I'm trying to identify the kinetics of the pivot PA#4 release but wondering whether my explanation below makes any sense to you. I've used Paul Wilson's overhead images and used white arrows for the force that would pulling on the left socket by the upper torso pivot. Then I've added some blue arrows to show the general rotational direction that would be felt by the left arm. Basically this is the same physics for the 'Release' of the club as explained by D'Alembert principle'. The eccentric force (ie. the white arrow) will cause a 'Moment of Force' (ie.a torque) on the left arm COM (Center Of Mass) and rotate it so that its COM aligns with the 'tail end' of that force vector. In the first image I drew a white arrow (F1) to represent a force if PW had immediately rotated his shoulder socket on a more curved path from P4. One can see that it would cause an OTT move of the left arm where the left arm would try and immediately align with F1. However, PW has moved his left shoulder socket more linearly towards the target and probably some vertical down motion from P4-P5 (see 2nd and 3rd images - F2 vector). I can't show you the vertical down motion from this birds-eye view but one can readily imagine that the left arm will move on a more vertical plane than an OTT move. I find this explanation helps me understand how the 'pivoted shoulder socket' can release PA#4 and move the left arm downwards without any pinning of the left humerus to the chest area. Do you think it is a realistic explanation or completely inaccurate? DG
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Post by imperfectgolfer on May 26, 2020 10:46:35 GMT -5
Dr Mann/UG /S I'm trying to identify the kinetics of the pivot PA#4 release but wondering whether my explanation below makes any sense to you. I've used Paul Wilson's overhead images and used white arrows for the force that would pulling on the left socket by the upper torso pivot. Then I've added some blue arrows to show the general rotational direction that would be felt by the left arm. Basically this is the same physics for the 'Release' of the club as explained by D'Alembert principle'. The eccentric force (ie. the white arrow) will cause a 'Moment of Force' (ie.a torque) on the left arm COM (Center Of Mass) and rotate it so that its COM aligns with the 'tail end' of that force vector. In the first image I drew a white arrow (F1) to represent a force if PW had immediately rotated his shoulder socket on a more curved path from P4. One can see that it would cause an OTT move of the left arm where the left arm would try and immediately align with F1. However, PW has moved his left shoulder socket more linearly towards the target and probably some vertical down motion from P4-P5 (see 2nd and 3rd images - F2 vector). I can't show you the vertical down motion from this birds-eye view but one can readily imagine that the left arm will move on a more vertical plane than an OTT move. I find this explanation helps me understand how the 'pivoted shoulder socket' can release PA#4 and move the left arm downwards without any pinning of the left humerus to the chest area. Do you think it is a realistic explanation or completely inaccurate? DG I don't understand how the fact that the left shoulder moves horizonally causes the left arm to mainly move downwards below left shoulder socket level - based on your analysis where the left arm's COM lines up with the force vector ? Jeff.
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Post by dubiousgolfer on May 26, 2020 18:06:09 GMT -5
Dr Mann Here is JS images where I've shown the white arrow force being applied by his pivoting shoulder socket. For image1 I didn't have enough room to draw the blue curved motion arrow depicting the rotation caused by the 'Moment of Force' by the white arrow (on the COM of the left arm). But you can see in image2 how the left arm rotates downwards to align its COM with the white force vector arrow. Even in image 4, where the shoulder socket abruptly moves up from the blue dot (P5) to the white dot (P5.5) , there is still a 'Moment of Force' rotation caused by the force applied by the pivot through his shoulder socket . JS is still TRYING to accelerate his left arm in image 4 but I can easily imagine its less than the acceleration he was creating from P4 to P5, plus there are other forces in play that will decelerate his left arm after P5.5 as the club releases. So the 'MOF' component applied to the left arm in the downwards vertical plane direction exceeds the 'MOF' component in the horizontal plane (ie. imho an OTT 'MOF' component, but I suspect its very small and won't cause much left arm abduction from P4-P5) Does this make more sense? DG
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Post by imperfectgolfer on May 26, 2020 21:22:56 GMT -5
DG,
I can see how you draw your MOF lines, but you are trying to use basic principles of physics to explain a biomechanical action. For example, it is obvious that the left shoulder socket is going upwards between image 3 and image 4, which means that the line of action of the MOF is changing to a more upwards direction - but that does not explain why the left hand is still going downwards by a large amount between image 3 and image 4. You are also ignoring the role of the right arm adduction maneuver in moving the hands downplane between P4 => P5.5.
Also, if the MOF is the major operant force between image 1 => image 3 due to the targetwards motion of the left shoulder socket, why is the line of action only operating in the vertical plane and not in the horizontal plane (which would cause the left arm to move from adduction => abduction) between image 1 and image 3?
Jeff.
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Post by dubiousgolfer on May 27, 2020 7:38:13 GMT -5
Dr Mann
The downwards MOF component is not the only 'torque' in operation (because one will also be using left/right shoulder girdle torques immediately after the pivot MOF).
Also there will be a horizontal component MOF (torque) happening but it will depend on how angulated the left arm is compared to the shoulder force 'white arrow' line at P4 (EXAMPLE: see Image 1 birds-eye view of PW -where the actual left socket pulling force is along that horizontal white line while the left arm is angulated behind). So there will be some left arm motion of the arm in the horizontal plane but imho a lot smaller than the downwards component.
Also, I doubt one will be able to see any significant change in the left arm adduction angle between upper arm and shoulder line because the upper torso is also rotating.
DG
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Post by imperfectgolfer on May 27, 2020 7:49:14 GMT -5
Dr Mann The downwards MOF component is not the only 'torque' in operation (because one will also be using left/right shoulder girdle torques immediately after the pivot MOF). Also there will be a horizontal component MOF (torque) happening but it will depend on how angulated the left arm is compared to the shoulder force 'white arrow' line at P4 (EXAMPLE: see Image 1 birds-eye view of PW -where the actual left socket pulling force is along that horizontal white line while the left arm is angulated behind). So there will be some left arm motion of the arm in the horizontal plane but imho a lot smaller than the downwards component. Also, I doubt one will be able to see any significant change in the left arm adduction angle between upper arm and shoulder line because the upper torso is also rotating. DG Why should the left arm motion be less in the horizontal plane than the vertical plane as result of that MOF's line of action? Why should upper torso rotation affect one's ability to see any significant change in the left arm adduction angle - when viewing a birds-eye view video? Jeff.
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Post by dubiousgolfer on May 27, 2020 8:36:07 GMT -5
Dr Mann "Why should the left arm motion be less in the horizontal plane than the vertical plane as result of that MOF's line of action?"If you look at the diagram below (FRONT VIEW) , the left arm (and its COM) makes a greater angle 'c' compared to the shoulder socket pivot force 'F' (compared to 'b' from the TOP VIEW). The formula for 'MOF' is as shown , so you can see that 'h' is far greater than 'd' so the downwards 'MOF' magnitude is also greater. "Why should upper torso rotation affect one's ability to see any significant change in the left arm adduction angle - when viewing a birds-eye view video?"If at P4 there isn't much passive tissue connection between the left upper arm and chest area , and if the horizontal components of angular velocity of the ribcage is greater than the horizontal component of the left arms angular velocity, then won't the torso 'catch' up with the left arm (even while there is a horizontal MOF component being applied to the arm)? So the angle between the upper left arm and chest might not visibly change by a significant degree. DG
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Post by dubiousgolfer on May 27, 2020 8:46:01 GMT -5
Below are previous images you posted of a one-armed golfer I can easily imagine that he is releasing PA#4 with his pivot force via his lead shoulder socket, but where the horizontal component of the MOF is greater than the vertical component. But we can't see any visible increase in the angle between his chest and upper lead arm between P4-P5 because his torso is moving at at greater angular velocity and catching up with his right arm (more passive tissue connection). DG PS. You can see that the chest area of his shirt is no longer stretched but crumpled at about P5 . Doesn't that suggest that his torso has caught up with his right arm?
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Post by imperfectgolfer on May 27, 2020 17:50:03 GMT -5
DB,
You wrote-: "If at P4 there isn't much passive tissue connection between the left upper arm and chest area , and if the horizontal components of angular velocity of the ribcage is greater than the horizontal component of the left arms angular velocity, then won't the torso 'catch' up with the left arm (even while there is a horizontal MOF component being applied to the arm)?"
You wrote-: "I can easily imagine that he is releasing PA#4 with his pivot force via his lead shoulder socket, but where the horizontal component of the MOF is greater than the vertical component. But we can't see any visible increase in the angle between his chest and upper lead arm between P4-P5 because his torso is moving at at greater angular velocity and catching up with his right arm (more passive tissue connection)."
Those opinions appear to be very sensible!
Jeff.
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Post by dubiousgolfer on May 28, 2020 7:51:01 GMT -5
Dr Mann
I'm wondering whether there is any pattern linking pelvic rotation to the pivot induced release of PA#4 with a more 'vertical MOF component' vs 'horizontal MOF component'?
For example between P4-P5, would a golfer like Ryan Moore who has high hands, have a more shift-rotate pelvic pattern where his lead shoulder movement is synonymous with his pelvic motion? The shift rotate pelvic action would assist the targetwards movement of his lead shoulder socket and create a larger vertical MOF component of his pivot induced PA#4 release (with minimal OTT horizontal component). Whereas a golfer like Matt Kucher , would have a more 'door hinge pelvic rotation' and therefore his shoulder pivot would reflect similarity and induce a pivot induced PA#4 release with a greater horizontal MOF component (on a flatter downswing plane).
Could it be that simple , that the pelvic rotary patterns in PGA Tour pros are connected to their various abilities to create power (really energy to be accurate from a physics perspective) in the early downswing in the vertical vs horizontal rotational planes?
DG
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Post by imperfectgolfer on May 28, 2020 11:31:39 GMT -5
DG,
I know of no reason why different patterns of pelvic shift-rotation during P4 => P5 will cause the degree of the horizontal component of the release of PA#4 to be significantly altered (increased) between P4 => P5.5.
I am not aware that Matt Kuchar has more of the horizontal component (left arm adduction => abduction) of the PA#4 release action happening between P4 => P5.5.
Stop the video at 1:08 minutes when he is st the P5.5 position. Note that his hands are about 12" outside his right thigh and there is no evidence that there was more left arm abduction happening between P4 => P5.5 (compared to Dustin Johnson or Cameron Champ).
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