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Post by imperfectgolfer on Feb 26, 2019 23:29:05 GMT -5
DB, My replies (in italics) are below each question. 1. Jon Sinclairs comments in first email response says "Moving toward flexion closes the club face at the top but then acts as an opens it at impact" "So these players having flexed lead wrist does not mean they have closed the club" Doesn't this support your own statement that bowing the wrist opens the clubface coming into impact? How does left wrist bowing close the clubface at the top? I believe that it has no effect on closing the clubface relative to the clubhead arc. Left wrist bowing only angles the clubshaft relative to the left forearm. At the top, Dustin Johnson's left wrist bowing maneuver changes the angle of the clubface relative to the left forearm and the ground - due to his "laying the club off". The clubface may be more horizontal to the ground at P4, but it is not more closed relative to the clubhead arc (which has been moved to a shallower, more horizontal alignment, secondary to the club becoming "laid-off"). That same degree of clubshaft angling at P6.5 also does not change the clubface relative to the clubhead arc. However, at P6.5 clubshaft angling affects the alignment of the clubface relative to the ball-target line due to the changed clubhead position.2. Your pictures showing lead arm supination from address to impact for Jon Rahm doesn't seem to tally with the 'magnified' JPEG image that Jon Sinclair emailed to me (shown above although I'm unsure how to make that picture bigger in this post) . The above jpeg shows MORE pronation at impact vs address which doesn't make sense to me because the Jon Rahm images clearly show less pronation at impact. Here is a copy of the Sinclair image.
Note that I have placed a red dot on the exact spot where the left forearm supination graph crosses the vertical impact line. I think that Jon is misrepresenting reality!
Further , Jon Sinclair says the following: " I would doubt highly that there is less or more forearm movement in a flexed wrist over a extended one."
He obviously does not understand that left wrist palmar flexion angles the clubshaft backwards (away from the target) and inwards (towards the body) relative to the left forearm in the later downswing, and I personally cannot understand how one can get a square clubface at impact from that situation without an extra degree of left forearm supination. Can you?
Could this difference between the images and 3D Graph be explained by the way 3D AMM measures supination and pronation (see Tyler Ferrells video below)? You use the antecubital fossa as a point of reference whereas TF seems to show a different method where supination/pronation of the wrist is compared to its alignment with the elbow (or will there no real difference in the methods used)? Theoretically, there should be no difference in quantifying the amount of left forearm happening during a PA#3 release action - even if there was a small difference in how it is measured.
3. What does Jon Sinclair mean when he says "AMM does not do the shoulder girdles so that can alter it some." ? How can shoulder girdle movement affect supination/pronation measurements? I cannot fathom why Jon believes that shoulder girdle movements will affect the amount of left forearm supination required to square a clubface during the late downswing.
4. I don't understand these comments below and wondering whether you have a clue?
"As a very general rule a player with a lot of flexion in their wrist at the top will actually start closing the club face later than one with a lot of extension. I am talking about world class players here. After club transition flexed players will tend to move toward extension a bit before going hard back to flexion." On what basis does he claim that pro golfers, who have an overtly bowed left wrist, close the clubface later in the downswing? Look at Jon Rahm's 3-D graph - note that the rapid phase of left forearm supination starts at the appropriate time (very soon after the release of PA#2 starts). There is no evidence that Jon Rahm is delaying his PA#3 release action. I think that the major factor determining the timing of the PA#3 release action depends on the angle of the left arm relative to the body and the accumulator #3 angle (as I have explained in topic 3 of my Finney Seminar review paper).
"John has what I would consider a normal motion of flexion for a player that is in so much flexion at the top. He is also a extreme outlier when it comes to flexion at the top. You can see it is as I predicted. He moves more toward extension after transition before he goes back quickly toward flexion. As I always say it is the motion not the position. This is a good motion with a extreme position.
I would say he closes the club face later than someone that is in extension at the top. This I believe is because flexed player go back to rad extension and extended players have no need to"
I have no idea what he is talking about in that bold-highlighted statement. Do you? You wrote-: "Addendum: I think I now understand why a flexed wrist will start closing the clubface later.That is because the clubshaft is angled back more from the target line and therefore needs to close later with more supination to square the clubface without causing too much shaft lean at impact (hope I've got this correct!)." I disagree! If the clubshaft is angled back more relative to the left forearm at P5.5 and also during the later downswing, it only means that more left forearm supination will be required to get a square clubface by impact. The timing of the start of left forearm supination will not necessarily be affected - why should it? Jeff.
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Post by imperfectgolfer on Feb 27, 2019 1:24:18 GMT -5
DB, Consider yet again this graph.
Note that I am suggesting that the left forearm supination graph crosses the vertical impact line at the red dot.
However, I strongly suspect that the graph is inaccurate and I think that impact is really where the yellow arrow is pointing - which is even further above the horizontal zero line. My reasoning is based on the fact that the graph has a plateau where there is no further left forearm supination temporarily happening - and biomechanical logic dictates that this must be the P7 => P7.2+ time period. It makes no biomechanical sense to believe that Jon Rahm is supinating his left forearm that much between the red dot and the yellow arrow through the immediate impact zone to P7.2 - because that would result in a non-DH hand release action.
The 3-D graph is captured at a 240HZ rate of sampling and it could easily be fractionally off at the time of impact - considering how steep the graph is immediately pre-impact and through impact.
Jeff.
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Post by dubiousgolfer on Feb 27, 2019 6:34:24 GMT -5
Many thanks again Dr Mann for this fantastic analysis.
DB
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Post by dubiousgolfer on Jun 10, 2019 8:17:44 GMT -5
Dr Mann I've been looking again at this section of your review. ---------------------------- So, look again at these capture images of Jamie Sadlowski's early downswing action. Image 1 is at his end-backswing position (P4 position). Note that his hands are vertically above his left shoulder socket (see green circle marker) because his left arm is at the 12 o'clock position relative to his left shoulder socket. If he then lowered his left arm so that it became parallel to the ground at his P5 position (image 3) while keeping his left shoulder socket in the same position as the green circle marker, then the extra distance that his hands would be further away from the target would be equal to the length of his left arm. However, his left shoulder socket has moved targetwards between P4 and P5 in his "real life" golf swing action and it is now at the blue circle marker position at his P5 position. That means that the extra distance that his left hand has moved further away from the target between P4 and P5 is equal to the length of his left arm minus the length of the distance between the green circle marker and the blue circle marker. What biomechanical actions cause Jamie Sadlowski's left arm to lower (depress) during the P4 => P5 time period? I believe that three biomechanical phenomena play a role in Jamie Sadlowski's left arm-lowering action that happens during his early downswing. First of all, when Jamie Sadlowski's upper torso rotates counterclockwise around his rightwards-tilted thoracic spine, thereby causing his left shoulder socket to move targetwards, it produces a targetwards pull on the left arm because the left humeral head must move along with the left shoulder socket. Because Jamie Sadlowski's left arm is near-vertical at the P4 position, the pulling motion due to the targetwards motion of the left shoulder socket passively pulls the left arm downwards as well as targetwards. Secondly, I can well imagine that Jamie Sadlowski is activating his left shoulder girdle muscles (eg. left lattisimus dorsi muscle) and that its isotonic muscular contraction can synergistically assist him in lowering (depressing) his left arm. Thirdly, I can readily imagine that Jamie Sadlowski's right palm may be applying a certain amount of push-pressure against pressure point #1 (PP#1), which is located at the base of the left thumb, in a downwards direction when he actively adducts his right arm during the early downswing's P4 => P5 time period. ------------------------------ I have highlighted the statements in red above which has caused me some confusion. If at P4, JS's upper torso is just rotating counterclockwise around the axis of his rightwards-tilted spine , why isn't the left shoulder joint path more circular? For the left shoulder joint to move targetwards in a straighter path as shown in the image above , then there must be lateral movement , not just rotation around axis of the tilted spine. If one surmised that net lateral movement of the the right hip joint towards the target at P4 (when weight pressured and stabilised in space at P4) will also cause a net lateral movement of the 'sacrum/pelvis' unit towards the target (when there is re-rotation around the stabilised right hip - due to the contraction of the pelvic girdle lateral rotary muscles between P4 -P5). Wouldn't this net lateral movement of the 'sacrum/pelvis' unit cause the entire spine and left shoulder joint to also move targetwards ? But that doesn't seem to be happening in JS's swing , because his head dips while he gains more right lateral flexion of his spine , but the top of his spine doesn't seem to have moved laterally. So how could his left shoulder joint have moved targetwards in such a straight path? Could it be that the straighter targetwards path of JS's left shoulder joint be due to some partial 'left scapula retraction' from P4-P5? DG
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Post by imperfectgolfer on Jun 10, 2019 9:21:39 GMT -5
Dr Mann I've been looking again at this section of your review. ---------------------------- So, look again at these capture images of Jamie Sadlowski's early downswing action. Image 1 is at his end-backswing position (P4 position). Note that his hands are vertically above his left shoulder socket (see green circle marker) because his left arm is at the 12 o'clock position relative to his left shoulder socket. If he then lowered his left arm so that it became parallel to the ground at his P5 position (image 3) while keeping his left shoulder socket in the same position as the green circle marker, then the extra distance that his hands would be further away from the target would be equal to the length of his left arm. However, his left shoulder socket has moved targetwards between P4 and P5 in his "real life" golf swing action and it is now at the blue circle marker position at his P5 position. That means that the extra distance that his left hand has moved further away from the target between P4 and P5 is equal to the length of his left arm minus the length of the distance between the green circle marker and the blue circle marker. What biomechanical actions cause Jamie Sadlowski's left arm to lower (depress) during the P4 => P5 time period? I believe that three biomechanical phenomena play a role in Jamie Sadlowski's left arm-lowering action that happens during his early downswing. First of all, when Jamie Sadlowski's upper torso rotates counterclockwise around his rightwards-tilted thoracic spine, thereby causing his left shoulder socket to move targetwards, it produces a targetwards pull on the left arm because the left humeral head must move along with the left shoulder socket. Because Jamie Sadlowski's left arm is near-vertical at the P4 position, the pulling motion due to the targetwards motion of the left shoulder socket passively pulls the left arm downwards as well as targetwards. Secondly, I can well imagine that Jamie Sadlowski is activating his left shoulder girdle muscles (eg. left lattisimus dorsi muscle) and that its isotonic muscular contraction can synergistically assist him in lowering (depressing) his left arm. Thirdly, I can readily imagine that Jamie Sadlowski's right palm may be applying a certain amount of push-pressure against pressure point #1 (PP#1), which is located at the base of the left thumb, in a downwards direction when he actively adducts his right arm during the early downswing's P4 => P5 time period. ------------------------------ I have highlighted the statements in red above which has caused me some confusion. If at P4, JS's upper torso is just rotating counterclockwise around the axis of his rightwards-tilted spine , why isn't the left shoulder joint path more circular? For the left shoulder joint to move targetwards in a straighter path as shown in the image above , then there must be lateral movement , not just rotation around axis of the tilted spine. If one surmised that net lateral movement of the the right hip joint towards the target at P4 (when weight pressured and stabilised in space at P4) will also cause a net lateral movement of the 'sacrum/pelvis' unit towards the target (when there is re-rotation around the stabilised right hip - due to the contraction of the pelvic girdle lateral rotary muscles between P4 -P5). Wouldn't this net lateral movement of the 'sacrum/pelvis' unit cause the entire spine and left shoulder joint to also move targetwards ? But that doesn't seem to be happening in JS's swing , because his head dips while he gains more right lateral flexion of his spine , but the top of his spine doesn't seem to have moved laterally. So how could his left shoulder joint have moved targetwards in such a straight path? Could it be that the straighter targetwards path of JS's left shoulder joint be due to some partial 'left scapula retraction' from P4-P5? DG You asked-: " I have highlighted the statements in red above which has caused me some confusion. If at P4, JS's upper torso is just rotating counterclockwise around the axis of his rightwards-tilted spine , why isn't the left shoulder joint path more circular?" The path of Jamie's left shoulder socket motion between P4 and P5 is circular - when viewed from a birds-eye viewing perspective. However, that circular path will look "straightish" if the circular path is viewed from a face-on viewing perspective because the circular path motion is roughly parallel to the ground. There is no need to postulate a need for any left-lateral motion of Jamie's spine to account for the "facts" seen in those capture images. I could certainly agree that his left shoulder retraction can account for some of the targetwards motion of the left shoulder socket along its circular path.
When the pelvis rotates counterclockwise between P4 and P5 due to the contraction of the right-sided lateral pelvic rotator muscles, there is no targetwards motion of the lumbo-sacral joint area in Jamie Sadlowskis' pelvic motion pattern because he keeps his pelvis centralised during his "Sam-Snead sit-down" move. In fact, his lumbo-sacral joint area will move away from the target between P4 and P5 secondary to the counterclockwise rotation of his pelvis - as seen in the following capture images.
Jeff.
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Post by dubiousgolfer on Jun 10, 2019 17:53:45 GMT -5
Dr Mann I've been looking again at this section of your review. ---------------------------- So, look again at these capture images of Jamie Sadlowski's early downswing action. Image 1 is at his end-backswing position (P4 position). Note that his hands are vertically above his left shoulder socket (see green circle marker) because his left arm is at the 12 o'clock position relative to his left shoulder socket. If he then lowered his left arm so that it became parallel to the ground at his P5 position (image 3) while keeping his left shoulder socket in the same position as the green circle marker, then the extra distance that his hands would be further away from the target would be equal to the length of his left arm. However, his left shoulder socket has moved targetwards between P4 and P5 in his "real life" golf swing action and it is now at the blue circle marker position at his P5 position. That means that the extra distance that his left hand has moved further away from the target between P4 and P5 is equal to the length of his left arm minus the length of the distance between the green circle marker and the blue circle marker. What biomechanical actions cause Jamie Sadlowski's left arm to lower (depress) during the P4 => P5 time period? I believe that three biomechanical phenomena play a role in Jamie Sadlowski's left arm-lowering action that happens during his early downswing. First of all, when Jamie Sadlowski's upper torso rotates counterclockwise around his rightwards-tilted thoracic spine, thereby causing his left shoulder socket to move targetwards, it produces a targetwards pull on the left arm because the left humeral head must move along with the left shoulder socket. Because Jamie Sadlowski's left arm is near-vertical at the P4 position, the pulling motion due to the targetwards motion of the left shoulder socket passively pulls the left arm downwards as well as targetwards. Secondly, I can well imagine that Jamie Sadlowski is activating his left shoulder girdle muscles (eg. left lattisimus dorsi muscle) and that its isotonic muscular contraction can synergistically assist him in lowering (depressing) his left arm. Thirdly, I can readily imagine that Jamie Sadlowski's right palm may be applying a certain amount of push-pressure against pressure point #1 (PP#1), which is located at the base of the left thumb, in a downwards direction when he actively adducts his right arm during the early downswing's P4 => P5 time period. ------------------------------ I have highlighted the statements in red above which has caused me some confusion. If at P4, JS's upper torso is just rotating counterclockwise around the axis of his rightwards-tilted spine , why isn't the left shoulder joint path more circular? For the left shoulder joint to move targetwards in a straighter path as shown in the image above , then there must be lateral movement , not just rotation around axis of the tilted spine. If one surmised that net lateral movement of the the right hip joint towards the target at P4 (when weight pressured and stabilised in space at P4) will also cause a net lateral movement of the 'sacrum/pelvis' unit towards the target (when there is re-rotation around the stabilised right hip - due to the contraction of the pelvic girdle lateral rotary muscles between P4 -P5). Wouldn't this net lateral movement of the 'sacrum/pelvis' unit cause the entire spine and left shoulder joint to also move targetwards ? But that doesn't seem to be happening in JS's swing , because his head dips while he gains more right lateral flexion of his spine , but the top of his spine doesn't seem to have moved laterally. So how could his left shoulder joint have moved targetwards in such a straight path? Could it be that the straighter targetwards path of JS's left shoulder joint be due to some partial 'left scapula retraction' from P4-P5? DG You asked-: " I have highlighted the statements in red above which has caused me some confusion. If at P4, JS's upper torso is just rotating counterclockwise around the axis of his rightwards-tilted spine , why isn't the left shoulder joint path more circular?" The path of Jamie's left shoulder socket motion between P4 and P5 is circular - when viewed from a birds-eye viewing perspective. However, that circular path will look "straightish" if the circular path is viewed from a face-on viewing perspective because the circular path motion is roughly parallel to the ground. There is no need to postulate a need for any left-lateral motion of Jamie's spine to account for the "facts" seen in those capture images. I could certainly agree that his left shoulder retraction can account for some of the targetwards motion of the left shoulder socket along its circular path.
When the pelvis rotates counterclockwise between P4 and P5 due to the contraction of the right-sided lateral pelvic rotator muscles, there is no targetwards motion of the lumbo-sacral joint area in Jamie Sadlowskis' pelvic motion pattern because he keeps his pelvis centralised during his "Sam-Snead sit-down" move. In fact, his lumbo-sacral joint area will move away from the target between P4 and P5 secondary to the counterclockwise rotation of his pelvis - as seen in the following capture images.
Jeff. Dr Mann The reason I thought the left shoulder was moving in a straighter lateral path towards target (ie. particularly left shoulder retraction) was that it explained the straighter hand path shown in the below image from point 1 to 2. But if you say that the left shoulder path is circular from a birds eye view , plus the hands are not moving further away from the right shoulder from P4-P5 , then wouldn't the 'real' hand path from point 1 to 2 (if looking down from a birds eye view normal to the intact LFFW plane) also be circular? Basically , if the 'upper torso/arms/club' are rotating as a unit (with fully loaded PAs) around the rightwards-tilted thoracic spine axis, then the hand path must be circular. If the above is incorrect and there really is a straighter hand path between point 1- 2 , could this be caused predominantly by a progressively increasing right lateral flexion of the spine? But if the top of his spine is not swaying more to the right due to lateral flexion (although there is a dip) , then doesn't that mean he must be moving his pelvis laterally targetwards? That there must be some direct relationship between lateral flexion of the spine and lateral movement of the pelvis to keep the top of the spine stable (ie. no sway away from target)? But if the hand path from point 1-2 is really circular , then why isn't release happening earlier? Could it be that JS is somehow 'holding the lag' (ie. negative wrist torque) and then allowing release when the hand path becomes even more circular between P2-P3? ------------------------------------------------------------------------------------ The red splined path is Jamie Sadlowski's hand arc path. Point 1 is the position of his hands at his end-backswing position. Point 2 is the position of his hands at the P5 position (when the left arm is parallel to the ground). Note that his hands are moving slightly backwards (away from the target), but mainly downwards, between point 1 and point 2 due to rotation of the upper torso that happens prior to the release PA#4. That section of the hand arc path is relatively straight, and it doesn't induce the club to release because there is very little change in the direction of left hand travel during that straight-line section of the hand arc path. ------------------------------------------- With reference to your statement: "When the pelvis rotates counterclockwise between P4 and P5 due to the contraction of the right-sided lateral pelvic rotator muscles, there is no targetwards motion of the lumbo-sacral joint area in Jamie Sadlowskis' pelvic motion pattern because he keeps his pelvis centralised during his "Sam-Snead sit-down" move. In fact, his lumbo-sacral joint area will move away from the target between P4 and P5 secondary to the counterclockwise rotation of his pelvis - as seen in the following capture images."I found this Gears video which seems to show lateral pelvic slide in transition. But am I correct in assuming that this 'lateral slide' has happened before JS has reached P4? I understand that Gears may not be a true reflection of reality because it uses smoothing algorithms (due to its low data measuring frequencies) plus its not showing JS's very strong grip (and even showing a palmar flexed left wrist at P5-P6 which looks incorrect), but have they also made an error in this measurement of net lateral pelvic slide towards target? DG
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Post by imperfectgolfer on Jun 10, 2019 18:56:57 GMT -5
You asked-: " I have highlighted the statements in red above which has caused me some confusion. If at P4, JS's upper torso is just rotating counterclockwise around the axis of his rightwards-tilted spine , why isn't the left shoulder joint path more circular?" The path of Jamie's left shoulder socket motion between P4 and P5 is circular - when viewed from a birds-eye viewing perspective. However, that circular path will look "straightish" if the circular path is viewed from a face-on viewing perspective because the circular path motion is roughly parallel to the ground. There is no need to postulate a need for any left-lateral motion of Jamie's spine to account for the "facts" seen in those capture images. I could certainly agree that his left shoulder retraction can account for some of the targetwards motion of the left shoulder socket along its circular path. When the pelvis rotates counterclockwise between P4 and P5 due to the contraction of the right-sided lateral pelvic rotator muscles, there is no targetwards motion of the lumbo-sacral joint area in Jamie Sadlowskis' pelvic motion pattern because he keeps his pelvis centralised during his "Sam-Snead sit-down" move. In fact, his lumbo-sacral joint area will move away from the target between P4 and P5 secondary to the counterclockwise rotation of his pelvis - as seen in the following capture images. Jeff. Dr Mann The reason I thought the left shoulder was moving in a straighter lateral path towards target (ie. particularly left shoulder retraction) was that it explained the straighter hand path shown in the below image from point 1 to 2. But if you say that the left shoulder path is circular from a birds eye view , plus the hands are not moving further away from the right shoulder from P4-P5 , then wouldn't the 'real' hand path from point 1 to 2 (if looking down from a birds eye view normal to the intact LFFW plane) also be circular? Basically , if the 'upper torso/arms/club' are rotating as a unit (with fully loaded PAs) around the rightwards-tilted thoracic spine axis, then the hand path must be circular. If the above is incorrect and there really is a straighter hand path between point 1- 2 , could this be caused predominantly by a progressively increasing right lateral flexion of the spine? But if the top of his spine is not swaying more to the right due to lateral flexion (although there is a dip) , then doesn't that mean he must be moving his pelvis laterally targetwards? That there must be some direct relationship between lateral flexion of the spine and lateral movement of the pelvis to keep the top of the spine stable (ie. no sway away from target)? But if the hand path from point 1-2 is really circular , then why isn't release happening earlier? Could it be that JS is somehow 'holding the lag' (ie. negative wrist torque) and then allowing release when the hand path becomes even more circular between P2-P3? ------------------------------------------------------------------------------------ The red splined path is Jamie Sadlowski's hand arc path. Point 1 is the position of his hands at his end-backswing position. Point 2 is the position of his hands at the P5 position (when the left arm is parallel to the ground). Note that his hands are moving slightly backwards (away from the target), but mainly downwards, between point 1 and point 2 due to rotation of the upper torso that happens prior to the release PA#4. That section of the hand arc path is relatively straight, and it doesn't induce the club to release because there is very little change in the direction of left hand travel during that straight-line section of the hand arc path. ------------------------------------------- With reference to your statement: "When the pelvis rotates counterclockwise between P4 and P5 due to the contraction of the right-sided lateral pelvic rotator muscles, there is no targetwards motion of the lumbo-sacral joint area in Jamie Sadlowskis' pelvic motion pattern because he keeps his pelvis centralised during his "Sam-Snead sit-down" move. In fact, his lumbo-sacral joint area will move away from the target between P4 and P5 secondary to the counterclockwise rotation of his pelvis - as seen in the following capture images."I found this Gears video which seems to show lateral pelvic slide in transition. But am I correct in assuming that this 'lateral slide' has happened before JS has reached P4? I understand that Gears may not be a true reflection of reality because it uses smoothing algorithms (due to its low data measuring frequencies) plus its not showing JS's very strong grip (and even showing a palmar flexed left wrist at P5-P6 which looks incorrect), but have they also made an error in this measurement of net lateral pelvic slide towards target? DG You asked-: " But if you say that the left shoulder path is circular from a birds eye view , plus the hands are not moving further away from the right shoulder from P4-P5 , then wouldn't the 'real' hand path from point 1 to 2 (if looking down from a birds eye view normal to the intact LFFW plane) also be circular? Basically , if the 'upper torso/arms/club' are rotating as a unit (with fully loaded PAs) around the rightwards-tilted thoracic spine axis, then the hand path must be circular." No! The hand arc path is moving on a totally different plane than the plane of left shoulder socket motion. The left shoulder socket is moving in a relatively horizontal plane where the arced nature of its path is best viewed from a birds-eye viewing perspective. The hands are moving on a much more vertical arced path - as seen in these DTL capture images of Jamie's downswing action. From a DTL viewing perspective, it would seem that the hand arc path has the same "arc of circularity" all the way between P4 and impact. However, we know that's not true when viewing his hand arc path from face-on. Also, note how his left shoulder socket is moving on a much more horizontal plane when viewed from a DTL viewing perspective. During that time period between image 1 and image 2 (when his left shoulder socket is moving mainly targetwards with no groundwards motion), note how much he has depressed his hands groundwards between image 1 and image 2. One can clearly see that he has a "straightish" hand arc path section between point 1 and point 2, and that it becomes much more "tightly" circular between point 2 and point 3. The speed of release of PA#2 is affected by the "tightness of circularity" in this plane because the plane of radial => ulnar deviation of the left wrist operates in this more vertical plane. I don't know how GEARS measures pelvic slide motion and whether they include the backswing phase. We know from Jamie's 3-D graph (below) that he starts rotating his pelvis counterclockwise well before P4 and he could indeed be having some pelvic slide motion during his late backswing between P3 and P4. When looking at Jamie's back view capture images, I can see no significant slide of his pelvis leftwards between image 1 and image 2 (using the trunk of that tree in the background as a reference point), and I can clearly see that his sacrum is rotating counterclockwise, which means that it is moving away from the target. Jeff.
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Post by dubiousgolfer on Jun 10, 2019 19:48:48 GMT -5
Many thanks Dr Mann - that makes more sense to me now. Does the right shoulder move on a different plane to the left shoulder? DG PS. It looks like they do according to this research article. The graphs fig 4 and fig 5 show different slopes between left and right shoulder for each category of golfer tested. pdfs.semanticscholar.org/0830/aae23a14ded06ae7a2a20aafd39e03005949.pdf
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Post by imperfectgolfer on Jun 10, 2019 23:41:59 GMT -5
Many thanks Dr Mann - that makes more sense to me now. Does the right shoulder move on a different plane to the left shoulder? DG PS. It looks like they do according to this research article. The graphs fig 4 and fig 5 show different slopes between left and right shoulder for each category of golfer tested. pdfs.semanticscholar.org/0830/aae23a14ded06ae7a2a20aafd39e03005949.pdfThe right shoulder socket does move on a different plane during the downswing than the left shoulder socket - especially because of the presence of right lateral bend of a variable amount. Also, there is "crunching" of the right side of the upper torso during the mid-late downswing while the left side of the upper torso is simultaneously extending/lengthening, and that must affect the path of right/left shoulder motion. That research paper has no relevance to this topic of shoulder socket motion because it does not discuss motions of the shoulder sockets in space and it only refers to motions of the left/right humerus within their respective shoulder sockets. Jeff.
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Post by dubiousgolfer on Jun 11, 2019 6:35:05 GMT -5
Many thanks again Dr Mann
DG
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Post by dubiousgolfer on Jun 13, 2019 5:35:02 GMT -5
Many thanks Dr Mann - that makes more sense to me now. Does the right shoulder move on a different plane to the left shoulder? DG PS. It looks like they do according to this research article. The graphs fig 4 and fig 5 show different slopes between left and right shoulder for each category of golfer tested. pdfs.semanticscholar.org/0830/aae23a14ded06ae7a2a20aafd39e03005949.pdfThe right shoulder socket does move on a different plane during the downswing than the left shoulder socket - especially because of the presence of right lateral bend of a variable amount. Also, there is "crunching" of the right side of the upper torso during the mid-late downswing while the left side of the upper torso is simultaneously extending/lengthening, and that must affect the path of right/left shoulder motion. That research paper has no relevance to this topic of shoulder socket motion because it does not discuss motions of the shoulder sockets in space and it only refers to motions of the left/right humerus within their respective shoulder sockets. Jeff. Dr Mann So when you say the right and left shoulder are moving on different planes , are you comparing their movements using a DTL view and the angle they make with the horizontal ground (ie. similar to hand/elbow/shoulder planes)? Does that mean they cannot 'both' be moving perpendicular to the tilted upper thoracic spine (as in image 2 below)? DG PS. Ignore my comment as I've just seen in your 'Downswing' chapter an explanation below Diagram 1 depicts the spine from a face-on view if the golfer stands erect with a straight spine (colored in blue). The shoulders are normally oriented perpendicular to the upper thoracic spine if the clavicles are horizontal to the ground - see solid red line. The red dotted lines show the range of depression/elevation of the shoulders that can occur if a golfer deliberately depresses/elevates the shoulders, and this phenomenon can occur unilaterally or bilaterally thus causing the affected shoulder to move at a non-perpendicular angle relative to the upper thoracic spine. Diagram 2 depicts a face-on view of a golfer who has i) secondary axis tilt causing the lower spine to become more rightwards-tilted and ii) lateral bending of the upper thoracic spine to the right (relative to the lumbar spine) and iii) a certain amount of right clavicle/shoulder depression that all synergistically interact to cause the right shoulder to move along a slightly more steeper path. Jamie Sadlowski is an example of a golfer who manifests all three biomechanical phenomena. One can clearly see that Jamie Sadlowski manifests all three biomechanical phenomena - i) significant secondary axis tilt, ii) right-lateral bending of the upper spine (relative to the lower spine), and iii) depression of the right shoulder - during his late downswing action. There is no "gold standard" rule that mandates a "fixed" right shoulder path during the downswing because different golfers have different physiques and different biomechanical motions of the spine and right shoulder. Each individual golfer can experiment to determine which of these biomechanical phenomena he can fruitfully utilize during his downswing action.
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Post by dubiousgolfer on Jun 13, 2019 6:16:03 GMT -5
Dr Mann
So looking at the above 3 biomechanical phenomena , doesn't this provide the criteria required to create that straightish downward hand path in JS (and other golfer swings)?
Could the adduction of the upper right arm (coupled with the above 3 biomechanical phenomena) be assisting 'linear' hand speed along that straighter path , while the pitch elbow above the right hip helps create that 'turning around the corner' hand path to evoke CF effect?
DG
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Post by imperfectgolfer on Jun 13, 2019 9:24:42 GMT -5
Dr Mann So looking at the above 3 biomechanical phenomena , doesn't this provide the criteria required to create that straightish downward hand path in JS (and other golfer swings)? Could the adduction of the upper right arm (coupled with the above 3 biomechanical phenomena) be assisting 'linear' hand speed along that straighter path , while the pitch elbow above the right hip helps create that 'turning around the corner' hand path to evoke CF effect? DG Factors like right lateral bend (due to "crunching" of the right upper torso) and depression of the right clavicle may affect the hand arc path to a small degree, but I don't think that it is a major factor responsible for creating Jamie's "straightish" hand arc path between P4 and P5.5. Look again at these face-on images of Jamie Sadlowski's downswing. In image 1 his hands are well above his head, but vertically above a point that is well outside his right upper thigh. In image 4, he has depressed his hands by a large amount to a position below waist level, but his hands are still vertically above a point that is well outside his right upper thigh. The major reason for that significant left hand depression is that he is depressing his left humerus at the level of his left shoulder socket joint far more than he is abducting his left humerus at the level of the left shoulder socket joint. Another major factor that contributes to making that combination possible is his right elbow pitch action. Note that when he performs a right elbow pitch motion (see images 3 and 4) that his right elbow is much closer to the target than his right hand - and his right forearm is angled away from the target so that the right hand is much further away from the target as a result of that right elbow pitch action. That right hand motion keeps the hand arc path moving more downwards, and less targetwards, during the mid-downswing and it helps to maintain the "straightish" downwards path of the hands. Then, after P5.5, the hand arc path can become more "tightly circular as his left arm abducts more across his body in a targetwards direction.
In summary, it is the motion of the two arms that is mainly responsible for creating the "straightish" hand arc path between P4 and P5.5, and not torso motions. However, note how much his right shoulder socket has dropped groundwards between P4 and P5.5 (due to right lateral bend + right clavicle depression) and it is necessary to make his right elbow pitch motion optimally efficient.
Jeff.
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Post by dubiousgolfer on Jun 13, 2019 18:11:26 GMT -5
Dr Mann - many thanks for this ( I think I understand the geometry now- although it was difficult to picture).
It almost seems that its akin to a taut string attaching his left shoulder socket to his right elbow. That the targetwards movement of the whole taut string (by the left shoulder socket) is offset by the rotating forearm (caused by the pitch elbow action - with angle between right forearm and humerus constant) that moves the right hand further away from target. Both actions happening at the same time, offsetting against each other and limiting 'net hand movement' either away or towards the target.
While the above is happening there is a greater downwards component of left humerus compared to its abduction. The combined effect is a straighter path.
I know the above is not an accurate biomechanical description but it does make it easier for me to picture how a straight path can be created.
DG
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Post by dubiousgolfer on Jun 16, 2019 11:08:50 GMT -5
Dr Mann
I am slightly confused now about what causes the 'release' of PA#4 in a TGM swinger.
You have stated the below:
--------------------------------------- The most common method of actively releasing PA#4 is the pivot-driven swing and it is the method used by the majority of PGA tour players.
Basically, there are three general types of pivot-driven swinging actions i) an upper body swinging action where the lower body remains static and the swinger rotates only his upper body ii) a total body swinging action where the golfer rotates his lower and upper torso at the same rotational speed - exemplified by Jim Hardy's one-plane swing (Hardy OPS) iii) a lower body swinging action where the lower torso (pelvis) turns first followed sequentially by a secondary rotation of the upper torso (shoulders) - exemplified by Ben Hogan's and Tiger Woods swing style.
During the first part of the pivot-driven downswing, when the upper torso rotates counterclockwise, the left upper arm temporarily remains in contact with the left pectoral area of the chest wall - which means that there is an increased sense of loading pressure at PP#4 and there is consequently no release of PA#4 in the early downswing. At a certain time-point in the downswing, the upper torso decelerates (speed of upper torso rotation decreases) and the inert left arm is catapulted passively away from the upper torso into a freewheeling left arm swinging motion. That represents the release of PA#4. Homer Kelley states in his TGM book [1], that one should "consider Pivot Thrust as Body Power blasting a Swinger's essentially inert left arm into orbit toward Impact". When a golfer initiates a pivot-driven release of PA#4, the pivot action usually starts with a pelvic shift-rotation movement, which is then immediately followed by an upper torso rotational movement. Many TGM swingers start the upper torso's rotary motion with an assertive thrust motion of the right shoulder in a downplane direction. That right shoulder thrust action causes the entire upper torso to rotate as a single unit, and the left arm is then passively pulled forward by the rotating upper torso.
* I now think that it is over-simplistic to think of the left arm as being a freewheeling inert lever in the later downswing that is simply catapulted away from the chest wall by an active pivot motion, because a golfer is also simultaneously using an active contraction of his left shoulder girdle muscles during the downswing to maintain the downward-forward speed of motion of the left arm, and the straightening right arm may also be applying push-pressure at PP#1 to synergistically assist in maintaining the forward momentum of the left arm. I have described the right arm's potential role in synergistically assisting in the release of PA#4
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For JS's downswing you mentioned the following: "The major reason for that significant left hand depression is that he is depressing his left humerus at the level of his left shoulder socket joint far more than he is abducting his left humerus at the level of the left shoulder socket joint."
So for JS (and maybe other golfers) who have greater downward components of PA#4 release, doesn't this mean that its the left (and right ) shoulder girdle muscles that are mainly responsible for releasing PA4# (not an active pivot)? If yes, then can they still be categorised as TGM swingers?
DG
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