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Post by dubiousgolfer on Jun 17, 2023 7:14:25 GMT -5
The control of upper body segment speed and velocity during the golf swingcore.ac.uk/reader/143873885?utm_source=linkoutInteresting article, specifically the findings below: 1. Interestingly, peak axial rotation velocities were not significantly different between the thorax and pelvis during the downswing.I'm assuming this means PEAK axial rotational velocities within the 'Transverse' or 'Horizontal' plane for thorax and pelvis are virtually the same. 2. The current study examined individual directions of motion and revealed that while axial rotation of the thorax segment is the highest contributor to thorax speed, lateral tilt also plays a key role in generating high overall angular speed of the thorax
Basically , one needs to add the angular velocities of the thorax for 'forward tilt rotation, lateral tilt rotation and axial rotation' to get the net angular speed of the thorax (about an instantaneous axis that is normal to its rotation in 3D space). 3. The relatively large variability in head and thorax coupling suggests that no single control strategy exists for skilled golfers, and that coaches may need to provide instruction on the general pattern of head motion but remain flexible enough to permit different control strategies.4. Furthermore, the strong coupling between the thorax and pelvis is presumably a method for simplifying the motor control strategies during the downswing, and a way of ensuring consistent motor patterns.This coordination strategy implies that skilled golfers place a greater importance on regulating the global motion of the thorax and pelvis rather than independently regulating motion in each direction. This finding has important practical implications for golf coaches. Through practice, the CNS can modify a pattern of muscle activity in an effort to utilise the most effective and simple movement strategy(Carson and Riek, 2001).
When instructing highly practised golfers, changes in technique may be difficult to maintain due to a reliance on a highly developed, simplified, and ingrained control strategy. Coaches should also recognise that due to a lack of practice and repetition, unskilled golfers may not have refined their control strategy and hence perform less fluid movements that are regulated according to direction. In the future it would be of considerable interest to determine whether the same coupling relationships observed for skilled golfers exist for unskilled golfers.ConclusionThe present study confirmed that the thorax segment has the highest peak speeds and peak velocities for the upper body during the downswing of professional golfers. It was also apparent from the large contributions of lateral tilt velocity to total segment angular speed, that analyses of trunk dynamics should not be merely restricted to the axial rotation direction. Analyses of coupling revealed that very strong coupling relationships exist for the thorax and pelvis, but not so for the head and thorax. The relatively large variability in head and thorax coupling suggests that no single control strategy exists for skilled golfers, and that coaches may need to provide instruction on the general pattern of head motion but remain flexible enough to permit different control strategies. Furthermore, the strong coupling between the thorax and pelvis is presumably a method for simplifying the motor control strategies during the downswing, and a way of ensuring consistent motor patterns.DG
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Post by imperfectgolfer on Jun 17, 2023 9:28:12 GMT -5
I think that's a worthless research paper.
It is obvious to me that there must be a close correlation between the pelvic and upper torso rotational velocities because of the biomechanical presence of the relatively rigid spine that only allows for a finite degree of torso-pelvic separation. By contrast, the head is suspended above the torso via the flexible cervical spine and there is no reason that there has to be a close correlation between the rotational motion of the head and torso.
I cannot think of any reason why this type of golf research can possibly contribute to the better teaching/execution of a full golf swing action.
This is his concluding statement-: "Furthermore, the strong coupling between the thorax and pelvis is presumably a method for simplifying the motor control strategies during the downswing, and a way of ensuring consistent motor patterns."
I think that he is totally wrong - because I think that it is extremely difficult for many developing golfers to develop a consistent motor pattern where the kinetic sequence is correct and where the pelvis leads the upper torso during the downswing action, thereby avoiding an "OTT move" golf swing action.
Jeff.
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Post by dubiousgolfer on Jun 17, 2023 17:48:47 GMT -5
Dr Mann I don't think it's completely worthless, although it seems to provide evidence that is obvious to most, that there is a strong coupling between pelvis/thorax movements. From an anatomical perspective , I am ignorant regarding the flexible nature of the cervical spine so I found that aspect of the research educational. What surprised me was the importance of the lateral tilt velocity to the overal rotational velocity of the thorax (see graphs below). It seems that the lateral tilt angular velocity of the thorax matches the axial rotational velocity in the downswing and is equally as important in the PA#4 release. So doesn't this research provide some evidence that golfers with fast lateral flexion (ramping up immediately in the downswing) are not just trying to get the trail shoulder further down towards the ball to avoid running of right arm (and help support a DH hand release action) but are also using it to create extra rotational speed of the thorax? Personally, it never occurred to me that the speed of lateral flexion was so important in generating the thorax angular velocities that we see in those kinematic sequence graphs. DG
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Post by imperfectgolfer on Jun 18, 2023 0:30:08 GMT -5
Dr Mann I don't think it's completely worthless, although it seems to provide evidence that is obvious to most, that there is a strong coupling between pelvis/thorax movements. From an anatomical perspective , I am ignorant regarding the flexible nature of the cervical spine so I found that aspect of the research educational. What surprised me was the importance of the lateral tilt velocity to the overal rotational velocity of the thorax (see graphs below). It seems that the lateral tilt angular velocity of the thorax matches the axial rotational velocity in the downswing and is equally as important in the PA#4 release. So doesn't this research provide some evidence that golfers with fast lateral flexion (ramping up immediately in the downswing) are not just trying to get the trail shoulder further down towards the ball to avoid running of right arm (and help support a DH hand release action) but are also using it to create extra rotational speed of the thorax? Personally, it never occurred to me that the speed of lateral flexion was so important in generating the thorax angular velocities that we see in those kinematic sequence graphs. DG You wrote-: " It seems that the lateral tilt angular velocity of the thorax matches the axial rotational velocity in the downswing and is equally as important in the PA#4 release." How can you conclude that thoracic lateral tilt angular velocity has any effect on the speed of release of PA#4? Jeff.
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Post by dubiousgolfer on Jun 18, 2023 6:38:37 GMT -5
Dr Mann This is your definition of the PA#4 unloading motion: I prefer to think of the left arm's PA#4-unloading motion happening three-dimensionally in "real life" 3-D space due to the left arm unloading motion happening simultaneously in two planes - i) moving from the left arm being adducted at P4 to the left arm becoming more abducted at impact and ii) moving from the left arm being elevated at P4 to the left arm becoming near-vertical by impact. To best measure the degree of PA#4 unloading at any time point during the downswing, I prefer to think of the distance traveled by the left hand in 3-D space away from its end-backswing position (where it was close to the right shoulder socket area) towards its impact position (where it is far away from the right shoulder socket area) and I do not only think of the change in that acute angle drawn between the left upper arm and the front of the upper chest (as depicted in that 2-D representational image from the TGM book). If one thinks of the PA#4 release (unloading) action as happening when the lead hand moves further away from its end-backswing position, then when does the start of the PA#4 release action first happen?If those golfers in the research article are actively right lateral tilting, isn't it likely that the right 'shoulder socket/right hand/left hand' are also being actively moved in 3D space from P4? Therefore, according to your definition, isn't this contributing to PA4# release? The fact that the magnitudes of the right lateral tilt are as high as the axial rotation from P4-P7 suggests that it might not be a dominant left sided driven body release of PA#4 (ie. that the right side of the body seems to be just as important). DG PS. There is also the below that I find puzzling: The images show the positions of peak angular speed for 'pelvis /thorax/arm/club' in the downswing but compare that to the linear work done on the club via the hands for 'peak thorax speed' position. It is a very small amount of linear work 17.4 J compared to the overall linear work done via the hands on the club in the downswing (238.7 J) Doesn't this mean the body pivot angular rotation hasn't contributed much to the hand forces along the hand path? After that position in the downswing, the thorax angular rotation is decelerating (as well as the pelvis), so it doesn't seem possible they contribute to linear work done on the club via the hands from P5.3 to P7. Therefore, doesn't this mean PA4# cannot be a major direct contributor to linear work done on the club via the hands?
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Post by imperfectgolfer on Jun 18, 2023 9:38:23 GMT -5
Dr Mann This is your definition of the PA#4 unloading motion: I prefer to think of the left arm's PA#4-unloading motion happening three-dimensionally in "real life" 3-D space due to the left arm unloading motion happening simultaneously in two planes - i) moving from the left arm being adducted at P4 to the left arm becoming more abducted at impact and ii) moving from the left arm being elevated at P4 to the left arm becoming near-vertical by impact. To best measure the degree of PA#4 unloading at any time point during the downswing, I prefer to think of the distance traveled by the left hand in 3-D space away from its end-backswing position (where it was close to the right shoulder socket area) towards its impact position (where it is far away from the right shoulder socket area) and I do not only think of the change in that acute angle drawn between the left upper arm and the front of the upper chest (as depicted in that 2-D representational image from the TGM book). If one thinks of the PA#4 release (unloading) action as happening when the lead hand moves further away from its end-backswing position, then when does the start of the PA#4 release action first happen?If those golfers in the research article are actively right lateral tilting, isn't it likely that the right 'shoulder socket/right hand/left hand' are also being actively moved in 3D space from P4? Therefore, according to your definition, isn't this contributing to PA4# release? The fact that the magnitudes of the right lateral tilt are as high as the axial rotation from P4-P7 suggests that it might not be a dominant left sided driven body release of PA#4 (ie. that the right side of the body seems to be just as important). DG PS. There is also the below that I find puzzling: The images show the positions of peak angular speed for 'pelvis /thorax/arm/club' in the downswing but compare that to the linear work done on the club via the hands for 'peak thorax speed' position. It is a very small amount of linear work 17.4 J compared to the overall linear work done via the hands on the club in the downswing (238.7 J) Doesn't this mean the body pivot angular rotation hasn't contributed much to the hand forces along the hand path? After that position in the downswing, the thorax angular rotation is decelerating (as well as the pelvis), so it doesn't seem possible they contribute to linear work done on the club via the hands from P5.3 to P7. Therefore, doesn't this mean PA4# cannot be a major direct contributor to linear work done on the club via the hands? You wrote-: " If those golfers in the research article are actively right lateral tilting, isn't it likely that the right 'shoulder socket/right hand/left hand' are also being actively moved in 3D space from P4? Therefore, according to your definition, isn't this contributing to PA4# release? The fact that the magnitudes of the right lateral tilt are as high as the axial rotation from P4-P7 suggests that it might not be a dominant left sided driven body release of PA#4 (ie. that the right side of the body seems to be just as important)." I think that the release of PA#4 is due to the combination of the pivot motion that causes a horizontal motion of the left shoulder socket + assistance from the contraction of the shoulder girdle muscles, and the two in combination moves the lead arm mainly downwards between P4 (end-backswing) => P5.5 (when lead hand speed reaches its maximum value). Whether the golfer is simultaneously acquiring right lateral bend does not affect the release of PA#4 although it does help a golfer to shallow the clubshaft. Some pro golfers develop a lot of right lateral bend (eg. Joaquin Niemann) and some pro golfers develop little right lateral bend (eg. Luke List) and I know of no biomechanical reason why the acquisition of right lateral bend should increase the speed of release of PA#4. Here is Luke List's downswing action between P4 => P5.5.
Note that his hands are no closer to the target at P5.5 (image 3) when his lead hand probably reaches its maximum hand speed value due to the release of PA#4.
Note that he has minimal right lateral bend happening between P4 => P5.5 and his right shoulder socket is not lower than his lead shoulder socket at P5.5.
I cannot fathom why one would believe that the presence of a greater degree of right lateral bend would increase the speed of release of PA#4.
You wrote-: "The images show the positions of peak angular speed for 'pelvis /thorax/arm/club' in the downswing but compare that to the linear work done on the club via the hands for 'peak thorax speed' position. It is a very small amount of linear work 17.4 J compared to the overall linear work done via the hands on the club in the downswing (238.7 J)
Doesn't this mean the body pivot angular rotation hasn't contributed much to the hand forces along the hand path? After that position in the downswing, the thorax angular rotation is decelerating (as well as the pelvis), so it doesn't seem possible they contribute to linear work done on the club via the hands from P5.3 to P7."
Linear work is due the speed of motion of the lead hand pulling the club handle down the hand arc path, and it correlates with the speed of release of PA#4, and not the speed of rotation of the upper torso. One needs to think of the lead shoulder motion between P4 => P5 (assisted by contraction of the shoulder girdle muscles) catapulting the lead arm mainly downwards between P4 => P5.5 (note that Luke List's lead arm is far less elevated at P5.5 compared to P4, with little change in its degree of adduction => abduction).
Jeff.
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Post by dubiousgolfer on Jun 18, 2023 11:46:42 GMT -5
Dr Mann
I think the graph would show right lateral bend angular velocity (ie. from a left lateral tilt position at the top of the backswing). So it might not show up as actual right lateral bend in your images above.
Your explanation does make sense to me.
I made a mistake in my PS comment as I didn't notice that the CHS was significantly high at 45.1 mph because I forgot to take into the account 'angular work' (not worth discussing).
DG
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Post by dubiousgolfer on Jun 19, 2023 7:59:46 GMT -5
Dr Mann You said in your previous post "Linear work is due the speed of motion of the lead hand pulling the club handle down the hand arc path, and it correlates with the speed of release of PA#4, and not the speed of rotation of the upper torso". I cannot understand why you are discounting the speed of rotation of the upper torso for the release of PA#4. For example , here is Dave Tutelman's image of the model that the golf scientists use for inverse dynamics calculations . DT states: The shoulders, arms, and hands are assumed to be a rigid triangle, hinged at the red centerlines. Those are the base of the neck which allows the triangle to turn, and the hands which allow the club to turn.So in inverse dynamics they have made assumptions different to your opinions because they assume the 'rigid triangle' is rotated about a hinge (ie. the upper body pivot) and is moving both arms. To make it clearer, see the image below that shows how the upper body pivot turn can cause push and pull forces via each arm that also have tangential components along the hand hub path. DT states: Let's start by reviewing the picture we saw before of the double-pendulum model of the swing. We must remember that the power comes from shoulder torque, which is generated from the ground up. The arms don't create the power, they transmit it from the shoulders to the hands. It is generated by large muscles between the feet (whose function is to provide a stationary base) and the shoulders.A torque is a push-pull pair of forces, separated by some distance. In the picture, the right arm push and left arm pull are separated by the width of the shoulders. Either or both (right arm push and/or left arm pull) can be used to transmit the torque.DT also states the following: Shoulder torque moves the hands in a circular arc, which provides the main power for the swing. But the torque has to be transmitted to the hands from the turning shoulders. Transmitting the torque is the work of the arms. The model assumes the arms to be a single rigid body. But in actuality, the hands can be driven along the circular arc by a pull from the left arm (blue arrow), a push from the right arm (purple arrow), or a combination of the two. Almost all instruction today focuses on the left arm pull, but there is no fundamental reason why any of the three choices could not be used. Just like the left-arm pull, the right-arm push has a component of its force that will move the hands along that circular arc. (Remember this diagram!). If I've interpreted DT correctly from one on his articles regarding Lee Comeaux swing analysis, the hands/club can be propelled along the hand path as follows: 1. Shoulder torque (I think DT is using this term as the upper body pivot and not specific independent shoulder girdle activity). This can cause push and pull forces via the trail and lead arm as shown in the previous image. 2. Independent pull of lead arm (The left-side pull involves the left side deltoid and latissimus dorsi, plus the triceps.). 3. Independent trail arm push (The right-side push involves the right side triceps, lats, and pectorals, with maybe a little biceps to start) To make it easier to see , I have shown the component forces along the hand path caused specifically by the rotation of the upper body pivot. Doesn't the above suggest that upper body pivot is also responsible for the 3D movement of the lead arm in 3D space and release of PA#4? It is contributing to the linear work done via the hands along the hand path. DG
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Post by imperfectgolfer on Jun 19, 2023 9:30:35 GMT -5
Dr Mann You said in your previous post "Linear work is due the speed of motion of the lead hand pulling the club handle down the hand arc path, and it correlates with the speed of release of PA#4, and not the speed of rotation of the upper torso". I cannot understand why you are discounting the speed of rotation of the upper torso for the release of PA#4. For example , here is Dave Tutelman's image of the model that the golf scientists use for inverse dynamics calculations . DT states: The shoulders, arms, and hands are assumed to be a rigid triangle, hinged at the red centerlines. Those are the base of the neck which allows the triangle to turn, and the hands which allow the club to turn.So in inverse dynamics they have made assumptions different to your opinions because they assume the 'rigid triangle' is rotated about a hinge (ie. the upper body pivot) and is moving both arms. To make it clearer, see the image below that shows how the upper body pivot turn can cause push and pull forces via each arm that also have tangential components along the hand hub path. DT states: Let's start by reviewing the picture we saw before of the double-pendulum model of the swing. We must remember that the power comes from shoulder torque, which is generated from the ground up. The arms don't create the power, they transmit it from the shoulders to the hands. It is generated by large muscles between the feet (whose function is to provide a stationary base) and the shoulders.A torque is a push-pull pair of forces, separated by some distance. In the picture, the right arm push and left arm pull are separated by the width of the shoulders. Either or both (right arm push and/or left arm pull) can be used to transmit the torque.DT also states the following: Shoulder torque moves the hands in a circular arc, which provides the main power for the swing. But the torque has to be transmitted to the hands from the turning shoulders. Transmitting the torque is the work of the arms. The model assumes the arms to be a single rigid body. But in actuality, the hands can be driven along the circular arc by a pull from the left arm (blue arrow), a push from the right arm (purple arrow), or a combination of the two. Almost all instruction today focuses on the left arm pull, but there is no fundamental reason why any of the three choices could not be used. Just like the left-arm pull, the right-arm push has a component of its force that will move the hands along that circular arc. (Remember this diagram!). If I've interpreted DT correctly from one on his articles regarding Lee Comeaux swing analysis, the hands/club can be propelled along the hand path as follows: 1. Shoulder torque (I think DT is using this term as the upper body pivot and not specific independent shoulder girdle activity). This can cause push and pull forces via the trail and lead arm as shown in the previous image. 2. Independent pull of lead arm (The left-side pull involves the left side deltoid and latissimus dorsi, plus the triceps.). 3. Independent trail arm push (The right-side push involves the right side triceps, lats, and pectorals, with maybe a little biceps to start) To make it easier to see , I have shown the component forces along the hand path caused specifically by the rotation of the upper body pivot. Doesn't the above suggest that upper body pivot is also responsible for the 3D movement of the lead arm in 3D space and release of PA#4? It is contributing to the linear work done via the hands along the hand path. DG DT wrote-: "The model assumes the arms to be a single rigid body. But in actuality, the hands can be driven along the circular arc by a pull from the left arm (blue arrow), a push from the right arm (purple arrow), or a combination of the two. Almost all instruction today focuses on the left arm pull, but there is no fundamental reason why any of the three choices could not be used. Just like the left-arm pull, the right-arm push has a component of its force that will move the hands along that circular arc. (Remember this diagram!)."
I strongly believe that most pro golfers use a pivot-driven TGM swinging action (lead arm swinging action), and that the trail arm is not used to push the club handle down the hand arc path. I also cannot fathom how the trail arm can be used to push the club handle down the hand arc path as implied in the DT-described model because the trail arm is not simply a straight rigid lever of fixed length that simply transmits energy from a rotating shoulder socket (as depicted in the DT-diagram) and where the trail arm is simply a passive lever. It is possible to use the trail arm to power the golf swing by using a TGM hitting action (using PA#1), but that is not the pivot-driven golf swing action described by DT where the trail arm is simply a passive lever of fixed length connecting the club handle to the trail shoulder socket. DTs' description is as follows-: "The shoulders, arms, and hands are assumed to be a rigid triangle, hinged at the red centerlines. Those are the base of the neck which allows the triangle to turn, and the hands which allow the club to turn." His assumption is totally wrong when it comes to describing what happens in "real life" in a pro golfer's full golf swing action!
A reminder: Here is the core body/arm motions in a TGM swinging (lead arm swinging) action.
Jeff.
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Post by dubiousgolfer on Jun 23, 2023 12:13:09 GMT -5
Dr Mann
I agree that the right arm is not pushing like that DT inverse dynamics model but let's assume in a real golfer that the lower and upper body pivot moves the right shoulder socket. This would involve axial rotation and right lateral flexion of the thorax that would move the right shoulder socket and upper arm in 3D space. If the right upper arm is being moved in space about the thorax rotational plane, doesn't this mean that the forearm and right hand is pulling down on the club too and triggering a partial release of PA#4 ? It may not be much , but it is adding to clubhead movement and therefore clubhead speed with the right shoulder thrusting action downplane. Theoretically, why can't a right arm swinging action also be timed to work together with the TGM body driven lead arm swinging action?
For example, on your website you mention the following: I recommend that a right arm swinger start the right arm swinging action by simultaneously i) throwing the right upper arm and ii) thrusting the right shoulder downplane, so that they move at roughly the same speed. The right upper arm throw action is actually an active adduction movement of the right upper arm towards the right side of the torso.
To reiterate, I am assuming you mean that the right shoulder girdle is doing the thrusting of the right shoulder downplane, but why can't it be a mix of thorax axial rotation and lateral flexion accelerating the right socket combined with shoulder girdle thrust downplane ? Surely that combination would add to the throwing action of the right arm , similar to 'skipping a stone'?
If timed properly , couldn't both a pivot driven right arm and TGM lead arm swinging action optimise the forces acting on the grip of the club to increase clubhead speed?
DG
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Post by imperfectgolfer on Jun 23, 2023 16:02:24 GMT -5
Dr Mann I agree that the right arm is not pushing like that DT inverse dynamics model but let's assume in a real golfer that the lower and upper body pivot moves the right shoulder socket. This would involve axial rotation and right lateral flexion of the thorax that would move the right shoulder socket and upper arm in 3D space. If the right upper arm is being moved in space about the thorax rotational plane, doesn't this mean that the forearm and right hand is pulling down on the club too and triggering a partial release of PA#4 ? It may not be much , but it is adding to clubhead movement and therefore clubhead speed with the right shoulder thrusting action downplane. Theoretically, why can't a right arm swinging action also be timed to work together with the TGM body driven lead arm swinging action? For example, on your website you mention the following: I recommend that a right arm swinger start the right arm swinging action by simultaneously i) throwing the right upper arm and ii) thrusting the right shoulder downplane, so that they move at roughly the same speed. The right upper arm throw action is actually an active adduction movement of the right upper arm towards the right side of the torso.To reiterate, I am assuming you mean that the right shoulder girdle is doing the thrusting of the right shoulder downplane, but why can't it be a mix of thorax axial rotation and lateral flexion accelerating the right socket combined with shoulder girdle thrust downplane ? Surely that combination would add to the throwing action of the right arm , similar to 'skipping a stone'? If timed properly , couldn't both a pivot driven right arm and TGM lead arm swinging action optimise the forces acting on the grip of the club to increase clubhead speed? DG You wrote-: " To reiterate, I am assuming you mean that the right shoulder girdle is doing the thrusting of the right shoulder downplane, but why can't it be a mix of thorax axial rotation and lateral flexion accelerating the right socket combined with shoulder girdle thrust downplane? Surely that combination would add to the throwing action of the right arm , similar to 'skipping a stone'?
If timed properly , couldn't both a pivot driven right arm and TGM lead arm swinging action optimise the forces acting on the grip of the club to increase clubhead speed?" Your first paragraph describes the biomechanics underlying a right arm swinging action. The major question is how does one synchronise the motion of the right hand that is due to a right arm swinging action with a motion of the left hand that is moving down the hand arc path between P4 => P5.5 in response to a pivot-induced release of the lead arm (release of PA#4).
Here is Dustin Johnson's early-mid downswing action between P4 => P5.5.
The lead hand is moving down his hand arc path between P4 => P5.5 at an increasing speed due to his pivot-induced release of his lead arm (release of PA#4). If his right hand is moving at the same speed, then it means that he has perfected his i) speed of right shoulder motion in a downplane direction and ii) his speed of right arm adduction and iii) his speed of right elbow straightening. If he then wants to add to the speed of motion of his club handle between P4 => P5.5 so that he can reach a slightly greater speed of his mid-hand point by P5.5, how would he consistently get the timing perfected? How does one perfectly synchronise a pivot-induced TGM swinging action (lead arm swinging action) with a right arm swinging action that is happening simultaneously?
Jeff.
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Post by dubiousgolfer on Jun 23, 2023 19:25:25 GMT -5
Yes , it does seem to be incredibly difficult to synchronise both.
Many thanks
DG
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