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Post by dubiousgolfer on May 4, 2019 8:59:25 GMT -5
Dr Mann I have been looking at several you-tube videos and wondering what your opinions are: 1. Stack And Tilt - If you look at video below , is Andy Plummer backtracking on his weight shift instruction in his book? I have the book and he is says 55/45 on the front foot at address,60/40 at P4, 70/30 at P5 , 90/10 at P7 , then continually increases on the front foot until it is 95/5 at finish. 2. Here is a video by someone called 'Frozen Divots' who claims various expertise in a variety of subjects but very vague in providing proof of his golf theory concepts. The reason I have even included this video is because it overlaps with : 1. Your discussed topic "Topic number 1: Is the "spine engine" responsible for inducing pelvic rotation during the early downswing time period? 2. Serge Gracovetsky belief that the motion of the spine is primarily responsible for inducing pelvic rotation (see image further below) 3.Kelvin Miyahira claiming that right lateral bend must start during the transition, and that it must even happen before the upper torso (shoulders) start turning, so that a golfer can acquire enough right lateral bend to induce an "interlocking gears" phenomenon, and his belief that this combined biomechanical phenomenon will allow a golfer to biomechanically induce pelvic rotation during the early downswing. Question: Frozen Divots states that if you just performed lateral flexion while standing upright , his pelvis will rotate clockwise if you looked at him from above (as he is a left handed golfer. But if you performed that lateral flexion while also having forward flexion , this will cause his pelvis to rotate anticlockwise. Do you think the real reason why he gets an anticlockwise pelvic rotation when he has forward flexion (while looking as if he is performing progressive left lateral flexion) is that he is actually contracting his left gluteus maximus (while his right foot is relatively unweighted)? DB
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Post by imperfectgolfer on May 4, 2019 9:42:52 GMT -5
Dr Mann I have been looking at several you-tube videos and wondering what your opinions are: 1. Stack And Tilt - If you look at video below , is Andy Plummer backtracking on his weight shift instruction in his book? I have the book and he is says 55/45 on the front foot at address,60/40 at P4, 70/30 at P5 , 90/10 at P7 , then continually increases on the front foot until it is 95/5 at finish. 2. Here is a video by someone called 'Frozen Divots' who claims various expertise in a variety of subjects but very vague in providing proof of his golf theory concepts. The reason I have even included this video is because it overlaps with : 1. Your discussed topic "Topic number 1: Is the "spine engine" responsible for inducing pelvic rotation during the early downswing time period? 2. Serge Gracovetsky belief that the motion of the spine is primarily responsible for inducing pelvic rotation (see image further below) 3.Kelvin Miyahira claiming that right lateral bend must start during the transition, and that it must even happen before the upper torso (shoulders) start turning, so that a golfer can acquire enough right lateral bend to induce an "interlocking gears" phenomenon, and his belief that this combined biomechanical phenomenon will allow a golfer to biomechanically induce pelvic rotation during the early downswing. Question: Frozen Divots states that if you just performed lateral flexion while standing upright , his pelvis will rotate clockwise if you looked at him from above (as he is a left handed golfer. But if you performed that lateral flexion while also having forward flexion , this will cause his pelvis to rotate anticlockwise. Do you think the real reason why he gets an anticlockwise pelvic rotation when he has forward flexion (while looking as if he is performing progressive left lateral flexion) is that he is actually contracting his left gluteus maximus (while his right foot is relatively unweighted)? DB I do not believe that Mike Bennett has changed his opinions on weight shift - based on that video. I think that Frozen Divots is incorrectly applying his "force" when he bends over into a golfer's posture and his pelvis is rotating away from the target because he is pushing in that direction. When I attempt that "right tilt" maneuver while adopting a golfer's standard bent-over posture, my pelvis rotates towards the target - as predicted by Gracovetsky. Frozen Divots is seemingly trying to operate according to Fryette's laws, but those laws have been shown not to be applicable - see the research study I referred to in my review paper at perfectgolfswingreview.net/spinalmotion.htmHere are the results of that study. Jeff.
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Post by dubiousgolfer on May 4, 2019 10:16:06 GMT -5
Many thanks Dr Mann - Coincidentally , just been looking at videos about Fryette's laws. Thanks for the link to your review paper.
DB
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Post by imperfectgolfer on May 5, 2019 15:52:04 GMT -5
Looking at "Frozen Divots" video again I just realized that he wrongly believes that acquiring a bent-over golfer's posture at address means that the lumbar spine is flexed. However, a skilled golfer bends over at the level of the hip joints and the lumbar spine should remain neutral (as it would be when standing erect) when a golfer acquires a bent-over posture at address.
Jeff.
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Post by dubiousgolfer on May 25, 2021 12:59:42 GMT -5
Dr Mann I have been looking at this 'Spinal Engine' concept in more depth and found an article below www.serola.net/research-category/structure/normal-movement/coupled-motion/Noted some remarks made by the author: ------------------------------------------- Panjabi et al. [5] confirmed some aspects of Lovett’s experiment with much greater precision as to the vertebral level and movement. He agreed with Pearcy & Tibrewal by stating that, in the upper lumbar vertebrae, lateral bending to one side produced spinal rotation to the same side and, at L5 to S1, lateral bending produced rotation to the contralateral side Thus, when considering the movement of individual lumbar vertebrae, Panjabi agrees with all of the above authors that the lower lumbar spine undergoes movement patterns opposite to the upper lumbar spine. Because L4-L5 area is a transition area between the opposing upper and lower lumbar areas, it may rotate either way, which may be influenced by the shape and starting position of the lumbar curve. This transitional aspect of L4-L5, along with greater movement at that level, creates higher stresses than at other lumbar levels and maybe the reason that L4-L5 has the highest incidence of disc degeneration. However, due to its ties to the ilia through the iliolumbar ligaments, L4 may, more often, move with L5. Muscular Involvement The lower quadratus lumborum fibers, attaching L4, and L5 to the ilium, are ligamentous in adults [8]. As such, L4 and L5 rotate and laterally flex with the ilium due to the non-elastic bond [3, 4]. Thus, while the spinouses of L1 to L3 rotate towards the convexity, the spinouses of L4 and L5 rotate towards the concavity. Other muscles also cause these counter-movements of the upper and lower lumbar vertebrae, including the psoas [2, 9], multifidus, and lumbar parts of the longissimus and iliocostalis [10]. --------------------------------- So if I've interpreted this correctly , whatever happens with regards pelvic rotation when lateral bend is happening at L5-S1 , there will always be opposite rotation happening from L1-L3. Doesn't this mean that if the pelvis moves counterclockwise (as will L4/L5-S1) due to right lateral bend , the upper lumber L1-L3 vertebrae (and the ribcage/shoulder girdle) will rotate clockwise? Does this means that there is twisting motion happening around the L4/L5 point in the spine which may cause increase stress and increase the likelihood of injury in that area? DG
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Post by imperfectgolfer on May 25, 2021 15:13:26 GMT -5
DG,
He does not give any measurements of the degree of rotation happening at the level of the upper-lower lumbar spine in that article. I suspect that it is only a few degrees and biomechanically insignificant in most people, especially if they are middle-aged or elderly.
Jeff.
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