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Post by imperfectgolfer on Feb 11, 2020 13:37:29 GMT -5
Watch this AMG-produced video on arm motion in the downswing. Watch the video between the 3:30 - 4:15 minute time point. The AMG instructors wrongly claim that the narrowing of the clubhead path during the early downswing (relative to the backswing's clubhead path) must solely be due to the shift of the body in a targetwards direction and that it must not be due to any narrowing secondary to right arm motion that pulls the right elbow closer to the body. In fact, they claim that the right elbow bend must be increasing slightly during the early downswing I think that they are totally wrong. I think that narrowing of the clubhead arc path between P4 and P5.5 in pro golfers is partly due to an active right arm adduction maneuver that moves the right arm closer to the right side of the torso without any significant change in the degree of bend of the right elbow. Consider Tiger Woods' early downswing action. Look at how much TW adducts his right arm closer to the right side of his torso between P4 (image 1) and P5.5 (image 5) while maintaining roughly the same degree of right elbow bend angle. In fact, look at how much TW's left shoulder socket has moved targetwards between P4 and P5.5 thereby pulling the left humeral head along with it - thereby narrowing the left hand's arc path. Surely, the right arm must simultaneously adduct to allow the right hand to follow along with the left hand along the narrowed hand arc path if the right elbow bend angle remains unchanged and if the right shoulder socket is further away from the target at P5.5 than it was at P4!!!! Jeff.
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Post by dubiousgolfer on Feb 11, 2020 19:00:31 GMT -5
Dr Mann AMG's straightening the right arm intent also doesn't seem to make sense from a physics perspective. If we look at Dave Tutelmans diagram below , one can easily see that a straightening of the right arm (against an extended left arm) will create a torque that will tend to rotate the club anti-clockwise (ie. early release of PA#2). DG
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Post by imperfectgolfer on Feb 12, 2020 10:00:18 GMT -5
Dr Mann AMG's straightening the right arm intent also doesn't seem to make sense from a physics perspective. If we look at Dave Tutelmans diagram below , one can easily see that a straightening of the right arm (against an extended left arm) will create a torque that will tend to rotate the club anti-clockwise (ie. early release of PA#2). DG I agree. AMG's straightening of the right arm also does not make sense from a practical perspective because it would predispose to an early release of PA#2. Pro golfers usually maintain roughly the same degree of right angle bend between P4 and P5.5. Jeff.
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Post by dubiousgolfer on Feb 18, 2020 22:11:01 GMT -5
Dr Mann
AMG have released another video but look at 8:00 -12:24 . It seems the GEARS data on 3 pros shows their trail elbow does straighten from P4-P5.
The 1st pro seems to straighten about 7 degrees- small change The 2nd pro seems to straighten about 26 degrees -moderate change The 3rd pro seems to straighten about 4 degrees - small change
But what I found peculiar is why I couldn't easily see any external rotation of their right humerus or any pitch elbow movements , even though GEARS shows shallowing of their clubshaft versus hand path.
Quite a strange drill they are demonstrating at the end with a dominant PA#1 release 'hitting' action.
DG
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Post by imperfectgolfer on Feb 18, 2020 23:41:18 GMT -5
DG,
A change in right elbow bend of 4-7 degrees between P4 and P5 is negligible and can be ignored. It is equivalent to roughly maintaining the degree of right elbow bend during the early downswing.
You wrote-: "But what I found peculiar is why I couldn't easily see any external rotation of their right humerus or any pitch elbow movements , even though GEARS shows shallowing of their clubshaft versus hand path."
I agree that it is very strange, and it could well be a GEARS-artifact where the avatar does not represent reality and where the GEARS-avatar's right elbow motion looks like a punch elbow motion rather than a pitch elbow motion. How can a golfer shallow the clubshaft relative to the hand arc path using a punch elbow motion?
Finally, look at Shaun Webb doing the drill between the 13:14 - 13:25 minute time point of the video - note how quickly he adducts his right upper arm against the right side of his torso and note that he is using a pitch elbow motion and not a punch elbow motion. That's exactly what SW does in his "real life" golf swing action.
Then look at the video between the 13:34-13:42 minute time point showing a DTL viewing perspective. Note how he shallows the clubshaft using an active right arm adduction maneuver where the right elbow drops down below the left elbow in the early downswing and note that he is using a pitch elbow motion of the right elbow where the right forearm becomes more supinated during the clubshaft shallowing action.
Note that any right arm straightening between P5 and P6 in his drill demo is not due to an active release of PA#1 but due to the fact that his right elbow must invariably passively straighten if he gets his hands below waist level, but he does not simultaneously get his right shoulder enough downplane due to the lack of right lateral bend.
Jeff.
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Post by dubiousgolfer on Feb 19, 2020 8:28:48 GMT -5
Many thanks Dr Mann
But what about that 2nd pro golfers straightening trail arm? He looks a bit like DJ to me and wondering whether a straightening right arm would just reduce his excessive palmar flexion between P4 and P5?
Why do AMG keep stressing about getting width in the downswing ? What do they mean and what relevance is width to creating clubhead speed?
DG
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Post by dubiousgolfer on Feb 19, 2020 8:54:16 GMT -5
Creating width in the early downswing between P4-P5 makes no sense from a physics perspective. In fact a more bent trail arm will create more force for a given torque by PA#4 release. Here is Tutelmans article . Here is a view looking down the spine of the golfer during the early part of the downswing. The shoulder torque is shown as a dotted black arrow, trying to turn the whole assembly of shoulders, arms, hands, and club counter-clockwise. Either arm can be used to transmit the torque, or both can share the load. But, in this position, they act rather differently than when both are extended: The left arm is extended across the chest. It typically exerts its force from the left shoulder all the way to the grip.[1] So the torque radius (the "lever arm") is the blue arrow. The right arm is folded next to the torso. If the right side is exerting the force to move the hands, it is the chain of limbs including the right shoulder and [folded] right arm. So the right side lever arm is the red arrow. Now a key point: The red arrow is shorter than the blue arrow. Why does that matter? Because the shoulder torque is transmitted to the hands by forces. A torque is a force acting over a distance -- a lever arm. The size of the torque is the force times the distance. Torque = Force * Distance Or, applying simple algebra: Force = Torque/Distance Therefore, for a given torque, a shorter lever arm means a bigger force and vice versa. DG
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Post by syllogist on Feb 19, 2020 10:19:04 GMT -5
Hi DG,
Correct! During the backswing, many pros' right arms are fairly straight until they get past left arm parallel to the ground. Can you image what would happen if they were to get their right arms fairly straight by the time left arm is parallel to the ground in the downswing?!!! No speed.
It's one thing to warn against increasing right arm bend to significantly less than an 80 degree angle. It's another thing to advocate for a quick loss of that angle as Sean demonstrates through the drill.
One can also point to the width of the torso as a short lever as the torso rotates instead of the bent right arm as a lever. The right arm will maintain bend until the left arm moves from its proximity to the chest.
S
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Post by imperfectgolfer on Feb 19, 2020 10:49:30 GMT -5
Many thanks Dr Mann But what about that 2nd pro golfers straightening trail arm? He looks a bit like DJ to me and wondering whether a straightening right arm would just reduce his excessive palmar flexion between P4 and P5? Why do AMG keep stressing about getting width in the downswing ? What do they mean and what relevance is width to creating clubhead speed? DG I presume that you are talking about the GEARS-avatar golfers when you talk about the 2nd golfer. I have not even bothered to look again at that video because I think that it is not useful to talk about "artificial" avatar images. Regarding your 2nd question, I suspect that the AMG instructors are mainly concerned about a narrow width scenario in the downswing where the right arm is jammed against the right side of the torso and where the golfer has too much right lateral bend. I can agree that one should not exaggerate any narrowing of the clubhead path in the early-mid downswing by getting the right arm jammed against the right side of a "crunched-in" torso that has too much right lateral bend, but I think that expanding the right elbow angle is also an unsuitable choice.
From my perspective, the answer is simple - during the P4 => P5.5 time period, the left arm should be kept straight and fully extended and the right elbow bend angle should remain unchanged. Then, the amount of right arm adduction needed is just enough for the right hand to reach the left hand. Right arm adduction will obviously be necessary because of the short distance between the right side of the torso and the left hand when the right scapula moves from being retracted at P4 to being far less retracted at P5.5 thereby moving the right shoulder socket closer to the left hand. Look at these images of Tiger Woods downswing.
Look at what is happening to the left hand between P4 (image 1) and P5 (image 4) as the left arm moves to becoming more horizontal relative to the ground. Look at the distance between the left hand and the right side of the torso. If TW maintains an unchanged right elbow bend angle, and if the right hand has to reach the left hand at the club handle, then a finite amount of right arm adduction must be present in order that the right arm/forearm can accomodate itself to the distance between the right shoulder socket and the left hand. Then, note that the left hand becomes even closer to the right side of the torso by P5.5 (image 5) when the left arm angles more groundwards, which means that even more right arm adduction is necessary if the right elbow's bend angle remains unchanged. The green curved line drawn along TW's spine shows that he does not have an exaggerated degree of right lateral bend between P4 and P5.5.
Jeff.
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Post by dubiousgolfer on Feb 19, 2020 18:50:51 GMT -5
Many thanks Dr Mann
DG
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Post by imperfectgolfer on Feb 20, 2020 12:57:30 GMT -5
UG posted the following video of Bryson DeChambeau in the thread on left foot spinning. Watch the video to note how wide BDC's clubhead arc is during his backswing because he uses an one-piece takeaway where he keeps his right arm straightened for most of the backswing before he folds it later after P3. Then note how narrow his clubhead arc is during his downswing. What is causing his narrow clubhead arc during his P4 => P5.5 time period? Here are capture images of his early-mid downswing. Image 1 is at P4, image 2 is at P4.5, image 3 is just passed P5 and image 4 is at P5.5. Note how you can see his right elbow below his left elbow at P4.5 (image 2) and it is a reflection of his active right arm adduction maneuver while maintaining his right elbow's bend angle. Note how his right upper arm is being adducted towards the right side of his torso at P5 (image 3) while he maintains his right elbow's bend angle. He is not widening his right elbow's bend angle as recommended by the AMG instructors. Note that he has a lot of right lateral bend by P5.5 (image 4) and that he has his right upper arm fully adducted against the right side of his torso while maintaining his right elbow's bend angle relatively unchanged - which the AMG instructors state is a "killer move".
Fortunately, Bryson DeChambeau is wise enough to not follow the wrongheaded golf instructional advice offered by the AMG instructors. Jeff.
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Post by imperfectgolfer on Feb 20, 2020 13:24:38 GMT -5
Here is the LPGA golfer Brittany Altomare's early-mid downswing action. Note that she is losing lag between P5 (image 2) and P5.8 (image 3) and it is associated with a widening of her right elbow's bend angle.
Why is it happening? Note how far back her right shoulder is at P5.8 due to her delayed upper torso rotation. Her right elbow must straighten by P5.5 if she gets her hands below waist level while her right shoulder socket is still far up-plane. Here, by comparison, are Bryson DeChambeau's early-mid downswing's capture images. Note how Bryson DeChambeau gets his right shoulder socket much further downplane by P5.5 due to a non-delayed upper torso rotation combined with right lateral bend - so that the distance between his hands (which are below waist level) and his right shoulder socket is far less, and he therefore can maintain a fully bent right elbow bend angle and thereby maximum clubhead lag. Jeff.
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Post by dubiousgolfer on Feb 21, 2020 5:56:35 GMT -5
Dr Mann
When I look at 3D Gear golf marker placement on the body, the video below at 1:23 shows a marker being put on the AC joint and I can also see one positioned on the wrist joint.
I cannot see any other way for Gears to measure left elbow flexion/extension except by using the varying distance between the AC and wrist joint markers.
But when I look at this animated video from 0:0 - 0:12 , the AC joint seems to slide over the humerus rounded head as the arm adducts. I can therefore imagine that as the arm elevates just above shoulder level while it bends at the elbow , the distance between the wrist and AC joint will be a false measurement of elbow flexion.
Wouldn't it be more accurate to measure elbow flexion using the varying distances between the centre of the humerus head and the wrist joint?
DG
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Post by imperfectgolfer on Feb 21, 2020 10:19:48 GMT -5
DG,
At the 0:49 minute time point of the video, Michael Neff shows how to place the elbow marker in position. Therefore, 3 markers (wrist, elbow and AC markers) can be used to assess the degree of right elbow bend with reasonable accuracy. I use the word "reasonable" because it would be better to have a marker placed at the level of the humeral head, and not at the AC joint. However, I wonder whether the GEARS system can really differentiate between a pitch and a punch elbow motion with reasonable accuracy - especially considering the fact that the wrist marker will be rotating a lot as the right forearm pronates/supinates while the humeral head will be sliding sideways under the acromium process at the AC joint as the humerus moves from abduction => adduction. It is also possible that scapula retraction => protraction actions can cause variable degrees of AC joint separation that will also affect the position of the humeral head relative to the AC marker placed on top of the shoulder.
Jeff.
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Post by dubiousgolfer on Feb 21, 2020 17:20:44 GMT -5
Many thanks Dr Mann - I'm wondering whether Shaun/Mike are aware that they are suggesting golf instruction based on questionable 3D Gear data? Yet they continue to delete You-Tube comments that might question their reasoning. Just doesn't seem right to me.
DG
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