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Post by dubiousgolfer on Nov 30, 2023 12:05:06 GMT -5
Quite an interesting video .
DG
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Post by imperfectgolfer on Dec 1, 2023 11:32:23 GMT -5
Quite an interesting video . DG I personally think that this AMG video is worthless because I disagree with many of their opinions. I totally reject their definition of the angles used to measure the degree of hip extension/flexion. They use the middle of the chest as the point of measurement (which makes no sense to me), and they do not define where exactly on the pelvis the measurement point is placed. I also reject the "idea" that there are different measurements on the lead and trail side because I use the lumbar spine connection to the center of the posterior pelvis as my reference point.
My mental concept when talking about the problem of "early extension" is the spinal bend inclination angle of the lumbar spine relative to the thighs (as perceived to be a single "average" thigh angle) and it only gives one an overall impression of the degree of anterior pelvic tilt-versus-posterior pelvic tilt due to changing tilts happening at the level of the hip joints. I think that the lumbar spine angle does not change significantly during the backswing. The lumbar spine tilt angle may increase slightly between P4 => P5 if the golfer performs an exaggerated squat move (like Milo Lines). Most pro golfers, who use the "standard pivot motion", will move significantly towards posterior pelvic tilt between P5 => P7, but Milo Lines (and Viktor Hovland) maintain a greater degree of anterior pelvic tilt during the later downswing and early followthrough. I also reject the AMG instructors opinion that the trail pelvis has to move away from the tush line when the lead pelvis moves back towards the tush line. In many skilled golfers, the trail buttocks remains abutted against the tush line between P4 => P5 when the trail buttocks moves back towards the tush line. Here are some visual examples. Jamie Sadloski's P4 => P5 early downswing action.
I drew a red line against the back side of JS's trail buttocks at P4 (image 1) and that represents his tush line. The back of his lead buttocks is obviously far away from his tush line. Image 2 is at P4.5 and image 3 is at P5. His trail buttocks has remained close to the tush line and it is not leaving the tush line between P4 => P5 while his lead buttocks is moving towards his tush line. There is also no significant change in his lumbar spinal bend inclination angle between P4 => P5. Jack Nicklaus early downswing (overhead view). Image 1 is at P4 - I have drawn a red line against the back of his trail buttocks and that represents his tush line. Image 3 is at P5 - where his lead buttocks has moved back to the tush line while his trail buttocks remains abutted against the tush line.
It is a fallacy to believe that the trail buttocks has to move forward away from the tush line in order for the lead buttocks to move back towards the tush line. Also, note that his lumbar spine bend inclination angle is not changing significantly between P4 => P5. Here is an example of an "early extension" (standing-up) swing fault. Image 1 is at P4 - I have drawn a red line against the back of his trail buttocks and that represents the tush line.
Image 3 is at P6. His trail buttocks has moved away from the tush line and the lead buttocks has not moved towards the tush line - his entire pelvis is thrusting towards the ball-target line and he has too much posterior pelvic tilt due to bilateral hip joint extension. I also reject Shaun Webb's claim that an exaggerated squat move has a "clubshaft steepener" effect. Here is Milo Lines downswing action. The red splined path is hand arc path. Milo squats between P4 (image 1) and P5 (image 3) due to increased hip joint flexion - but he is actually shallowing his clubshaft during that time period.
I also reject Shaun Webb's claim that a squat move during the early downswing impairs a golfer's ability to rotate the pelvis and that it causes a "backing-up" swing fault. Here are capture images of Milo Lines downswing action. Milo is squating between P4 (image 1) and P5 (image 2) but that does not impair his ability to rotate his pelvis counterclockwise between P4 => P7. Also, his pelvis is not really "backing-up" - remember that Milo is a reverse-foot golfer and it is naturally expected that the outer border of his lead pelvis will remain well inside his lead foot at P7 when his pelvis rotates a lot counterclockwise between P4 => P7.
Jeff.
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Post by dubiousgolfer on Dec 1, 2023 19:57:50 GMT -5
Dr Mann The AMG anatomical marker placement is quite strange so I don't know if it can be used correctly to define early extension but it does show a variation in angles during the golf swing, measured at the trail and lead sides. As far as I am aware , early extension is when the centre of the pelvis moves towards the ball-target line in the backswing or early downswing, compared to its position at address. So they seem to be measuring the angle formed by a triangular plane formed by 3 marker positions, the centre of the chest, hips and knee joints (as per image below which is only showing the trail side triangle). To see that actual angle in 3D , one would need to view it from a position normal to that plane. DG PS. The centre of the pelvis does actually move towards the ball-target line if the pelvis is rotating around the trail hip, but that isn't early extension unless that forward position is maintained or even increases during the downswing too. Explained in this Dr Phil Cheetham video.
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Post by playing18 on Dec 1, 2023 22:52:14 GMT -5
Hi Dr. Mann,
It is an interesting topic as DG suggests.
I’m not sure why the AMG instructors call it “early” extension. If it is done on time it shouldn’t be called “early” or confused as a fault. Extension done on time is correct while early extension is a swing fault. It’s probably best to use these terms correctly.
I agree that pelvic rotation can continue as part of the squat move. However, as AMG suggests a bilateral squat move without rotation is a fault as is bilateral early extension with or without pelvic rotation. I think we all agree with that.
How AMG defines right and left side extension may suit their purposes but it seems odd and I have a hard time seeing how the lead side flexes in the downswing and how the trail side extends. Plus, it doesn’t seem to provide any instructional purpose.
We know in the standard pivot that players do a posterior pelvic tilt coming into impact. DJ’s belt buckle clearly rotates upward as he moves into p7. Isn’t this a telltale sign of a PPT?
Can you see how the information in this AMG video could also explain how to do a PPT while flexing the lead side? It seems impossible to explain but maybe you can do it. To me, the lead hip joint is extending to facilitate the PPT, not flexing.
During the downswing, as long as the tailbone doesn’t come off the tush line, isn’t it okay for the trail hip joint to rotate closer to the ball target line from p4 to p5? Isn’t this considered acceptable motion? Certainly the trail hip joint rotates closer to the ball target line in the later downswing.
In the early downswing we certainly don’t want both hips to extend closer to the BTL or to delay pelvic rotation due to a sustained bilateral hip flexion.
In sum, as far as this specific topic goes, don’t we want an active pelvic rotation, to keep our tail bone on the tush line as the pelvis rotates, and do a PPT (standard pivot) as DJ demonstrates, coming into impact?
Jim playing18
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Post by dubiousgolfer on Dec 2, 2023 9:13:53 GMT -5
Hi Jim
I'm also having a hard time seeing how the lead side flexes in the downswing and how the trail side extends but if you look at this video below, it sort of suggests a possibility. If the obliques are still contracting approaching P7, won't it tend to pull/rotate the ribcage diagonally closer to the lead side of the pelvis and reduce that measured angle?
I certainly don't 'feel' as if my lead side is flexing more into impact, quite the opposite in fact, so maybe that's a clue that I'm weak in utilising my oblique muscles.
DG
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Post by imperfectgolfer on Dec 2, 2023 10:38:20 GMT -5
Dr Mann The AMG anatomical marker placement is quite strange so I don't know if it can be used correctly to define early extension but it does show a variation in angles during the golf swing, measured at the trail and lead sides. As far as I am aware , early extension is when the centre of the pelvis moves towards the ball-target line in the backswing or early downswing, compared to its position at address. So they seem to be measuring the angle formed by a triangular plane formed by 3 marker positions, the centre of the chest, hips and knee joints (as per image below which is only showing the trail side triangle). To see that actual angle in 3D , one would need to view it from a position normal to that plane. DG PS. The centre of the pelvis does actually move towards the ball-target line if the pelvis is rotating around the trail hip, but that isn't early extension unless that forward position is maintained or even increases during the downswing too. Explained in this Dr Phil Cheetham video. DG, You wrote-: "The AMG anatomical marker placement is quite strange so I don't know if it can be used correctly to define early extension but it does show a variation in angles during the golf swing, measured at the trail and lead sides. As far as I am aware , early extension is when the centre of the pelvis moves towards the ball-target line in the backswing or early downswing, compared to its position at address." Your comments make no sense to me. When I think of the swing fault of "early extension" I think of the the pelvis going from a condition of anterior pelvic tilt to a condition of posterior pelvis tilt and it is a "standing-up" phenomenon because if the pelvis moves towards posterior pelvic tilt then a line drawn perpendicular to the pelvic axis between the upper sacrum and the symphysis pubis becomes more vertical. That "early extension" change can occur with, or without, a pelvic thrust motion in the direction of the ball-target line. It is also possible for the center of the pelvis to move towards the ball-target line without any change in pelvic tilt angle - and that would not represent an "early extension" swing fault. I also cannot accept that the measurement of changes in pelvic tilt angle can involve a point in the mid-thoracic area of the chest because it is possible for that angle to change if the golfer extends/flexes the upper torso even if he does not change his pelvic tilt angle. Phil Cheetham's graph is measuring pelvic thrust, and it is not measuring changes in the pelvic tilt angle.
You also wrote-: "So they seem to be measuring the angle formed by a triangular plane formed by 3 marker positions, the centre of the chest, hips and knee joints (as per image below which is only showing the trail side triangle)."
I agree that they are measuring that angle, and I can agree that the measurements on the trail side will be different to measurements on the lead side, but I cannot understand how that measurement is of value from a golf instructional perspective.
Jeff.
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Post by imperfectgolfer on Dec 2, 2023 11:05:26 GMT -5
Hi Dr. Mann, It is an interesting topic as DG suggests. I’m not sure why the AMG instructors call it “early” extension. If it is done on time it shouldn’t be called “early” or confused as a fault. Extension done on time is correct while early extension is a swing fault. It’s probably best to use these terms correctly. I agree that pelvic rotation can continue as part of the squat move. However, as AMG suggests a bilateral squat move without rotation is a fault as is bilateral early extension with or without pelvic rotation. I think we all agree with that. How AMG defines right and left side extension may suit their purposes but it seems odd and I have a hard time seeing how the lead side flexes in the downswing and how the trail side extends. Plus, it doesn’t seem to provide any instructional purpose. We know in the standard pivot that players do a posterior pelvic tilt coming into impact. DJ’s belt buckle clearly rotates upward as he moves into p7. Isn’t this a telltale sign of a PPT? Can you see how the information in this AMG video could also explain how to do a PPT while flexing the lead side? It seems impossible to explain but maybe you can do it. To me, the lead hip joint is extending to facilitate the PPT, not flexing. During the downswing, as long as the tailbone doesn’t come off the tush line, isn’t it okay for the trail hip joint to rotate closer to the ball target line from p4 to p5? Isn’t this considered acceptable motion? Certainly the trail hip joint rotates closer to the ball target line in the later downswing. In the early downswing we certainly don’t want both hips to extend closer to the BTL or to delay pelvic rotation due to a sustained bilateral hip flexion. In sum, as far as this specific topic goes, don’t we want an active pelvic rotation, to keep our tail bone on the tush line as the pelvis rotates, and do a PPT (standard pivot) as DJ demonstrates, coming into impact? Jim playing18 Jim, You wrote-: " I agree that pelvic rotation can continue as part of the squat move. However, as AMG suggests a bilateral squat move without rotation is a fault as is bilateral early extension with or without pelvic rotation. I think we all agree with that." I have never seen a pro golfer perform a squat move without rotating the pelvis. Golfers who perform a squat move (eg. Tiger Woods, Rory McIlroy and Viktor Hovland) do it when the pelvis is rotating ~40-50 degrees counterclockwise during the hip-squaring phase between P4 => P5.
You wrote-: "We know in the standard pivot that players do a posterior pelvic tilt coming into impact. DJ’s belt buckle clearly rotates upward as he moves into p7. Isn’t this a telltale sign of a PPT?"
Yes. If a golfer goes from anterior pelvic tilt => posterior pelvic tilt then the belt buckle will point less groundwards. However, I prefer to look at the angle formed between the trail thigh and a line drawn away from the trail hip joint where that line is drawn parallel to the lumbar spine - that angle becomes larger as one moves towards posterior pelvic tilt.
You wrote-: "During the downswing, as long as the tailbone doesn’t come off the tush line, isn’t it okay for the trail hip joint to rotate closer to the ball target line from p4 to p5? Isn’t this considered acceptable motion?"
I don't know how it is possible for the trail hip joint to move closer to the ball-target line if the trail buttocks area near the sacrum still remains abutted against the tush line - as seen in the following capture images.
You wrote-: "In sum, as far as this specific topic goes, don’t we want an active pelvic rotation, to keep our tail bone on the tush line as the pelvis rotates, and do a PPT (standard pivot) as DJ demonstrates, coming into impact?"
I think that it is useful for the reference point of the right buttock area (and not the sacrum as a reference point) to remain close to the tush line during the hip-squaring phase that happens between P4 => P5 and it should then move away from the tush line as the pelvis continues to rotate more open between P5 => P7.
Jeff.
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Post by imperfectgolfer on Dec 2, 2023 11:15:07 GMT -5
Hi Jim I'm also having a hard time seeing how the lead side flexes in the downswing and how the trail side extends but if you look at this video below, it sort of suggests a possibility. If the obliques are still contracting approaching P7, won't it tend to pull/rotate the ribcage diagonally closer to the lead side of the pelvis and reduce that measured angle? I certainly don't 'feel' as if my lead side is flexing more into impact, quite the opposite in fact, so maybe that's a clue that I'm weak in utilising my oblique muscles. DG How can the lead side of the upper torso be flexing in the late downswing due to contraction of the external abdominal obliques as that phenomenon would lower the lead shoulder socket? In all pro golfers the lead shoulder socket is elevating higher in the later downswing between P5.5 => P7 - and part of that phenomenon is due to elevation of the lead hip joint and part of it is due to stretching-out of the lead mid-upper torso area. Jeff.
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Post by dubiousgolfer on Dec 2, 2023 11:31:55 GMT -5
Dr Mann
"When I think of the swing fault of "early extension" I think of the the pelvis going from a condition of anterior pelvic tilt to a condition of posterior pelvis tilt and it is a "standing-up" phenomenon because if the pelvis moves towards posterior pelvic tilt then a line drawn perpendicular to the pelvic axis between the upper sacrum and the symphysis pubis becomes more vertical. That "early extension" change can occur with, or without, a pelvic thrust motion in the direction of the ball-target line. It is also possible for the center of the pelvis to move towards the ball-target line without any change in pelvic tilt angle - and that would not represent an "early extension" swing fault. I also cannot accept that the measurement of changes in pelvic tilt angle can involve a point in the mid-thoracic area of the chest because it is possible for that angle to change if the golfer extends/flexes the upper torso even if he does not change his pelvic tilt angle. Phil Cheetham's graph is measuring pelvic thrust, and it is not measuring changes in the pelvic tilt angle."
Yes that makes more sense as a definition but it seems Dr Phil Cheetham defines it differently (which is what I was using). In his video from 2:24 he mentions a female pupil having "stable early extension" because she thrust her centre of pelvis forward in the backswing and retained it in the downswing , actually moving forward a bit more before impact . But yes, she could have drifted forward while retaining her pelvic tilt and therefore not early extended as per your definition.
DG
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Post by dubiousgolfer on Dec 3, 2023 6:45:12 GMT -5
Looking at that video again , I don't think AMG are measuring the 3D angle from a viewpoint which is normal to the the plane formed by the 3 position markers. In the video they were changing only the 'Down The Line' camera angle which means they seem to be measuring 'projected angles' which do not reflect the anatomical reality.
DG
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Post by imperfectgolfer on Dec 3, 2023 10:03:50 GMT -5
Looking at that video again , I don't think AMG are measuring the 3D angle from a viewpoint which is normal to the the plane formed by the 3 position markers. In the video they were changing only the 'Down The Line' camera angle which means they seem to be measuring 'projected angles' which do not reflect the anatomical reality. DG They are probably using 3D measurements via GEARS and not from a camera viewpoint that is normal to any plane. I don't care how they obtain their measurements because I cannot fathom how they could be useful from a golf instructional perspective. Jeff.
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Post by playing18 on Dec 3, 2023 11:31:48 GMT -5
Dr. Mann and DG,
A basic principle of the AMG video is that a good swing involves never moving the right side of the body like the left side and vice versa. When one side flexes the other side extends. When one side adducts the other side abducts. When one side pronates the other side supinates.
However, what about the PPT motion coming into impact? Doesn’t DJ’s entire pelvis rotate as one unit causing the belt buckle to rise. Isn’t this essentially a bilateral event? Perhaps the lead side pelvic muscles drive the PPT more than the trail side pelvic muscles, or vice versa, but aren’t both sides involved in this important PPT motion. And when it’s done early, doesn’t this represent the early extension fault?
Jim playing18
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Post by imperfectgolfer on Dec 3, 2023 13:09:07 GMT -5
Dr. Mann and DG, A basic principle of the AMG video is that a good swing involves never moving the right side of the body like the left side and vice versa. When one side flexes the other side extends. When one side adducts the other side abducts. When one side pronates the other side supinates. However, what about the PPT motion coming into impact? Doesn’t DJ’s entire pelvis rotate as one unit causing the belt buckle to rise. Isn’t this essentially a bilateral event? Perhaps the lead side pelvic muscles drive the PPT more than the trail side pelvic muscles, or vice versa, but aren’t both sides involved in this important PPT motion. And when it’s done early, doesn’t this represent the early extension fault? Jim playing18 When I think of the biomechanical condition of anterior pelvic tilt versus posterior pelvic tilt, I think of a line drawn from the symphysis pubis to the top of the sacrum. That line is centrally situated in the pelvis and it is measured relative to the ground. So, if that line becomes more horizontal as the golfer approaches impact, it indicates a motion towards posterior pelvic tilt even if the two hip joints are at different heights and in different conditions of hip joint flexion/extension that can cause the line to tilt as perceived from a side-to-side perspective so that the degree of pelvic tilt at the level of each hip joint will be different. Here is Ben Hogan's pelvic motion going through impact. Hogan's pelvis is in a condition of posterior pelvic tilt which causes his lumbar spine bend angle to become more vertical, but his pelvis is asymmetrically aligned from side-to-side because of the different heights of the two hip joints and that causes the lumbar spine to also be tilted sideways.
Early extension during the early downswing between P4 => P5 can be associated with, or without, lumbar spine tilt depending on whether the degree of hip joint extension happening at each of the two hip joints is symmetric or asymmetric.
Jeff.
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Post by dubiousgolfer on Dec 6, 2023 18:27:53 GMT -5
Dr Mann/Jim
It seems that AMG have been making some very unscientific videos and the one in my opening post is a poor one. A software expert advised me that GEARS cannot make measurements as shown in that video in my opening post. That the only way they could have made those measurements would be using AVATAR images, putting dots on the screen and then using some 2D measuring tool.
The same can be said about any videos they've made about internal and external shoulder rotation.
Many of their videos contain some good data but they are also prone to making videos just to market themselves or other products like HackMotion.
DG
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