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Post by dubiousgolfer on Nov 5, 2020 0:03:33 GMT -5
Just found this article which I've never seen before (see attachment). The part in the conclusion that caught my attention is below: (3) the skilled group aligned the left hand plane with the FSP closely, whereas the less skilled group aligned the left shoulder plane with the FSP; (4) the FSP was located closer to the mid-trunk point and whole body CM in the skilled group than in the less skilled, resulting in a lower plane position in the skilled group. Does this mean that the right elbow has a more important part to play in controlling the swing center (ie. a paddling effect from P6-P7 ) in skilled players than the left shoulder socket in less skilled players? 5641-Article Text-16433-1-10-20130903.pdf (287.89 KB) DG
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Post by imperfectgolfer on Nov 6, 2020 11:40:49 GMT -5
Just found this article which I've never seen before (see attachment). The part in the conclusion that caught my attention is below: (3) the skilled group aligned the left hand plane with the FSP closely, whereas the less skilled group aligned the left shoulder plane with the FSP; (4) the FSP was located closer to the mid-trunk point and whole body CM in the skilled group than in the less skilled, resulting in a lower plane position in the skilled group. Does this mean that the right elbow has a more important part to play in controlling the swing center (ie. a paddling effect from P6-P7 ) in skilled players than the left shoulder socket in less skilled players? View AttachmentDG I cannot personally perceive of any golf instructional value in performing this type of comparative analysis. Many pro golfers, who are all very skilled, will have very different results when measured in this manner. Why should I even bother to compare the body/arm/hand motions of Jim Furyk versus Sergio Garcia, or Sergio Garcia versus Byrson DeChambeau, or Hunter Mahan versus Bubba Watson? How would the measurements help me to better understand golf swing biomechanics? Jeff.
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Post by dubiousgolfer on Nov 6, 2020 20:18:30 GMT -5
Just found this article which I've never seen before (see attachment). The part in the conclusion that caught my attention is below: (3) the skilled group aligned the left hand plane with the FSP closely, whereas the less skilled group aligned the left shoulder plane with the FSP; (4) the FSP was located closer to the mid-trunk point and whole body CM in the skilled group than in the less skilled, resulting in a lower plane position in the skilled group. Does this mean that the right elbow has a more important part to play in controlling the swing center (ie. a paddling effect from P6-P7 ) in skilled players than the left shoulder socket in less skilled players? View AttachmentDG I cannot personally perceive of any golf instructional value in performing this type of comparative analysis. Many pro golfers, who are all very skilled, will have very different results when measured in this manner. Why should I even bother to compare the body/arm/hand motions of Jim Furyk versus Sergio Garcia, or Sergio Garcia versus Byrson DeChambeau, or Hunter Mahan versus Bubba Watson? How would the measurements help me to better understand golf swing biomechanics? Jeff. It does change my perception of the 'DP' model's proximal arm and that the mid trunk is where the pivot rotation is being powered from for the 15 skilled golfers used in that research especially in the 'functional swing plane' from P6-P8. The video below shows the DP proximal arm in 'Red'. DG
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Post by dubiousgolfer on Nov 6, 2020 21:17:36 GMT -5
Here is some more information from Dr Kwon's website The FSP can be used in various ways in assessing the swing characteristics of the golfer. For example, the rotation of the body and club can be simplified to the motions of two levers rotating on the FSP (Figure 5). Not only the upper and lower lever angles, but also angles of various body lines (such as the pelvis and shoulder line angles and the X-factor) can be computed on the FSP and used in scrutinizing the swing motion of the golfer. More over, swing styles can be classified based on how the clubhead moves with respect to the FSP. Figure 5. The on-plane angular motion of the upper and lower levers in the functional double-pendulum perspective. The moving hub is located at the mid-trunk point, the mid-point of the tip of sternum and the spinous process of T12. The upper lever is the line connecting the hub and the mid-hand point. The length of the upper lever changes as the shoulder girdles and arms move. The lower lever is the club. DG
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Post by imperfectgolfer on Nov 7, 2020 0:38:39 GMT -5
DG, You wrote-: " It does change my perception of the 'DP' model's proximal arm and that the mid trunk is where the pivot rotation is being powered from." The idea that the proximal arm of an imaginary DP model is an imaginary arm (in red in the video) connected to an imaginary mid-trunk point makes no sense to me - because it is imaginary and not anatomically-based. I believe in the useful applicability of a TGM-based DP model where the lead arm is equivalent to the DP's central arm and where the pivot connects to the central arm at the level of the left shoulder socket joint - because it is based on anatomical reality in a TGM swinging action. I cannot fathom how it would be conceptually useful to think of an imaginary central arm (in red in the video) connected to the mid-torso point. How would it improve my understanding of how best to perform a full golf swing action?
You also quoted Dr. Kwon as follows-: "More over, swing styles can be classified based on how the clubhead moves with respect to the FSP." I have no idea what he is talking about - what swing styles? How does the clubhead move differently relative to the FSP in these different swing styles?
Jeff.
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Post by dubiousgolfer on Nov 7, 2020 6:51:11 GMT -5
DG, You wrote-: " It does change my perception of the 'DP' model's proximal arm and that the mid trunk is where the pivot rotation is being powered from." The idea that the proximal arm of an imaginary DP model is an imaginary arm (in red in the video) connected to an imaginary mid-trunk point makes no sense to me - because it is imaginary and not anatomically-based. I believe in the useful applicability of a TGM-based DP model where the lead arm is equivalent to the DP's central arm and where the pivot connects to the central arm at the level of the left shoulder socket joint - because it is based on anatomical reality in a TGM swinging action. I cannot fathom how it would be conceptually useful to think of an imaginary central arm (in red in the video) connected to the mid-torso point. How would it improve my understanding of how best to perform a full golf swing action?
You also quoted Dr. Kwon as follows-: "More over, swing styles can be classified based on how the clubhead moves with respect to the FSP." I have no idea what he is talking about - what swing styles? How does the clubhead move differently relative to the FSP in these different swing styles?
Jeff.
Dr Mann The idea of a TGM based DP model maybe more real but it doesn't seem to apply to the 15 skilled golfers used in that research article . If they had used a TGM based DP model type swing , I would imagine it may have matched more closely with the results found in the less skilled golfers (ie. lead shoulder plane matching more closely to FSP). Both concepts may have flaws , the TGM based DP swing (from a physics perspective) and a virtual proximal arm used by Dr Kwon (from an anatomical perspective) . But if the FSP plane bisects the mid-trunk , that infers that the source of the clubheads centre of rotation (from P6-P8) is directed nearer the mid-trunk area and not the lead shoulder socket . With regards swing styles based on clubhead movement relative to FSP , I wouldn't know but I might send Dr Kwon an email and ask for examples . I'm not wholly convinced by that research article because its not a very large sample of golfers but the results are rather surprising. DG
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Post by imperfectgolfer on Nov 7, 2020 10:36:51 GMT -5
DG,
You wrote-: "But if the FSP plane bisects the mid-trunk , that infers that the source of the clubheads centre of rotation (from P6-P8)is directed nearer the mid-trunk area and not the lead shoulder socket."
I don't think there is any such entity as a center-of-rotation for the clubhead arc, and I cannot imagine how it would be useful to even postulate the presence of an imaginary center-of-rotation in the mid-trunk area. Between P6 => P7 the shape of the clubhead arc, and the FSP's angle relative to the ground, is determined by the shape/path of the hand arc path (which is significantly affected by the angle of the left arm relative to the ground) and the accumulator #3 angle.
You also stated-: "If they had used a TGM based DP model type swing, I would imagine it may have matched more closely with the results found in the less skilled golfers (ie. lead shoulder plane matching more closely to FSP).
I disagree! I think that the left shoulder socket's motional plane does not significantly affect the FSP, which is mainly determined by the angle of the lead arm (relative to the ground) and the magnitude of the accumulator #3 angle.
Jeff.
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Post by dubiousgolfer on Nov 8, 2020 10:26:31 GMT -5
Dr Mann I tend to think there is a centripetal pull by the paddling right forearm when it pitch elbows just after P5.5 . The 'pull' is directed more towards the mid-trunk region and that seems to be closer to the 'virtual centre of rotation' for the clubheads curvilinear motion from P6-P7. Note: I made an error in this previous post and it should have said ' the 'virtual centre of an imaginary proximal arm of a 'Double Pendulum' from P6-P7. One might be able to visualise that 'pull' force in the previous images you posted in an earlier thread. DG
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Post by dubiousgolfer on Nov 8, 2020 11:23:06 GMT -5
When I look back at Dr Kwon's graphs below , it suggests to me that the decreasing but positive hand couple (red line) at P5.5 (when red and green lines cross) is not being used to influence the release of PA#2 but being used to alter the swing plane from P5.5 to the FSP (at about P6) Red Line - Hand Couple Green Line - M-of-F torque Blue Line - Net Torque DG
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Post by imperfectgolfer on Nov 8, 2020 14:19:38 GMT -5
Dr Mann I tend to think there is a centripetal pull by the paddling right forearm when it pitch elbows just after P5.5 . The 'pull' is directed more towards the mid-trunk region and that seems to be closer to the 'virtual centre of rotation' for the clubheads curvilinear motion from P6-P7. One might be able to visualise that 'pull' force in the previous images you posted in an earlier thread. DG I cannot understand why you believe that a pitch elbow motion of the trailing elbow creates a centripetal pull. I think that it primarily helps the lead am create a desired hand arc path. Also, one can create a similar-shaped hand arc path without the addition of a "trailing arm adduction maneuver combined with a pitch elbow motion" as seen in the following swing video of the one-armed golfer (Aldridge). I think that it makes no sense to think of an imaginary center-of-rotation in the mid-torso area in Aldridge's lead arm-only golf swing action as being a relevant factor in his ability to create his FSP. If one adds a "trailing arm adduction maneuver combined with a pitch elbow motion" to the mix it must simply be performed correctly so that it can synergistically assist the lead arm in creating an optimised hand arc path. When learning how to perform a good quality "trailing arm adduction maneuver combined with a pitch elbow motion", one should be focused on the motion of the trailing limb relative to the trailing side of the torso, and I cannot fathom how it would be better to visualize its motion relative to an imaginary virtual center-of-rotation located in the mid-torso.
Jeff.
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Post by imperfectgolfer on Nov 8, 2020 14:21:33 GMT -5
When I look back at Dr Kwon's graphs below , it suggests to me that the decreasing but positive hand couple (red line) at P5.5 (when red and green lines cross) is not being used to influence the release of PA#2 but being used to alter the swing plane from P5.5 to the FSP (at about P6) Red Line - Hand Couple Green Line - M-of-F torque Blue Line - Net Torque DG I have no idea why you believe that postulated assertion! Jeff.
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Post by dubiousgolfer on Nov 8, 2020 18:07:12 GMT -5
Here are some ultra slow motion images of Paul Wilson's swing from above. I cannot be 100% certain because the camera needs to be pointing parallel to the instantaneous plane of the swing , but there is a suggestion of backward bend of the shaft in the 'horizontal plane' which means there is a positive hand torque happening in the horizontal plane (as shown by the circular arrows near the hands). All these graphs by Dr Kwon and Dr Sasho Mackenzie show 'in plane ' couples and MOF, so they will not necessarily show the full hand couple magnitude and direction (just an 'In Plane' component) . Isn't it possible that the change from a more vertical to shallower swing plane is caused by that hand torque and what one is seeing in those Kwon/MacKenzie graphs is just a small 'in plane' component which has an insignificant effect on PA#2 release? DG
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Post by dubiousgolfer on Nov 8, 2020 19:04:37 GMT -5
Here's another top view video of Bryson where the camera is pointing more parallel to his swing plane. Pity the clubhead disappeared on the right side , but there is a suggestion of a little backward shaft bend in the horizontal plane. Maybe because he is not shifting plane too much from P5.5 -P6.
DG
I wish we could see the 'In Plane Couples /MOF' graphs for Bryson . If my postulation is correct then I'd doubt there would be any significant 'positive' hand couple torque when those 2 graph lines cross.
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Post by imperfectgolfer on Nov 9, 2020 10:23:42 GMT -5
DG,
You wrote-: "All these graphs by Dr Kwon and Dr Sasho Mackenzie show 'in plane ' couples and MOF, so they will not necessarily show the full hand couple magnitude and direction (just an 'In Plane' component) . Isn't it possible that the change from a more vertical to shallower swing plane is caused by that hand torque and what one is seeing in those Kwon/MacKenzie graphs is just a small 'in plane' component which has an insignificant effect on PA#2 release?"
The concept of the hand couple torque and MoF are only applicable to in-plane forces/torques. They have nothing to do with any clubshaft shallowing phenomenon that may happen between P4 => P6, and which require out-of-plane forces. I cannot understand why you would think that these in-plane forces/torques are insignificant in terms of releasing PA#2! What other forces could possibly be inducing a passive release of PA#2?
Jeff.
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Post by dubiousgolfer on Nov 9, 2020 17:58:51 GMT -5
DG, You wrote-: " All these graphs by Dr Kwon and Dr Sasho Mackenzie show 'in plane ' couples and MOF, so they will not necessarily show the full hand couple magnitude and direction (just an 'In Plane' component) . Isn't it possible that the change from a more vertical to shallower swing plane is caused by that hand torque and what one is seeing in those Kwon/MacKenzie graphs is just a small 'in plane' component which has an insignificant effect on PA#2 release?" The concept of the hand couple torque and MoF are only applicable to in-plane forces/torques. They have nothing to do with any clubshaft shallowing phenomenon that may happen between P4 => P6, and which require out-of-plane forces. I cannot understand why you would think that these in-plane forces/torques are insignificant in terms of releasing PA#2! What other forces could possibly be inducing a passive release of PA#2? Jeff. I think any small release of PA#2 caused by that residual positive hand couple is insignificant in increasing clubhead speed because it is applied for an incredibly small time period. But I'm trying to explain why there is still a positive hand couple when those red and green graphs cross over. DG ps. I need to reflect on this again. My thought process: P4- P5.5 1. Right hand force across the shaft causes a negative 'In Plane MOF' (ie . assists lag) 2. Right and Left hand produces a positive 'In plane hand couple' (which would tend to release PA#2 3. Left hand force across the shaft causes a positive 'In Plane MOF' (which would tend to release PA#2) 2+3 is slightly greater than 1 and will not cause any significant release of PA#2 . If the right hand 'In Plane Positive Hand Couple' moves to a more horizontal plane from P5.5-P6 to shallow the swing plane, then there is less likelihood of an early PA#2 release (ie. the net 'In Plane Positive Hand Couple' will be less). Therefore a golfer who shallows the swing plane will have less net positive 'In Plane' hand couple when the MOF takes over (ie. the red and green lines in Dr Kwon's graph would cross closer to the zero axis). If my postulation is correct , the inverse dynamics graph for golfers like Phil Mickelson and Bryson DeChambeau (who do not shallow the swing plane by very much) would show the red and green lines cross when there is more positive net 'In Plane' hand couple and a greater likelihood of a small early release of PA#2 before the MOF takes over.
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