New review paper on the effects of lead wrist bowing

[imperfectgolfer]

See - perfectgolfswingreview.net/LeadWristBowing.html

In this review paper, I have corrected a number of gross errors that I made in my you-tube video devoted to this topic (and which I have since removed from my you-tube channel), and this review paper represents my present day thinking on this topic.

Criticism will always be welcomed because it allows me to correct errors and constantly improve my thinking re: golf swing biomechanics.

Jeff.

[dubiousgolfer]

Dr Mann

I am just reading through the article and I will be adding my thoughts to this post as I gradually find issues that confuse me.

The first issue I have is this image below:



1. Your forearm seems to have angularly moved upwards in image 2 relative to image 1 (it could be a change in camera position that gives that impression). So that gives the added impression that the clubshaft has moved angularly downwards rather than just by increased ulnar deviation.
2. I cannot bow and radial deviate my lead wrist but I can bow and ulnar deviate excessively which will cause some supination and close the clubface.
3. I think JS must have bowed and excessively ulnar deviated his lead wrist and caused some supination that closed that clubface 13 degrees. Him putting his right finger on the radial bone of his left wrist will stop pronation but not some supination.

I'm not sure about this sentence

"Then, if he maintains a bowed lead wrist all the way between P6 => P7, thereby reaching impact with forward shaft lean (= backwards angulation of the clubshaft relative to the lead forearm due to lead wrist bowing), that means that the forces acting on the club handle are acting in a targetwards direction. " 

Looking at some of the graphs from Choi shows that the right hand force ends up pointing away from the target . The left hand force looks as if its virtually zero or slightly towards the target but I am unsure in what direction the net force is pointing.

I don't understand this paragraph, especially the part that I have underlined.

"Note that it is an obvious biomechanical fact that in order for a golfer (who uses a weak-neutral left hand grip) to maintain a GFLW all the way throughout the entire downswing between the P4 position (where the left wrist is radially deviated) to impact (where the left wrist is ulnar deviated), the left wrist angle must continuously change from being significantly dorsiflexed at P4 to becoming far less dorsiflexed (and even slightly palmar flexed) by impact."

Do you mean that it appears as if  "the left wrist angle must continuously change from being significantly dorsiflexed at P4 to becoming far less dorsiflexed (and even slightly palmar flexed) by impact."  

The reason I mention this is because of your earlier sentence
" it does alter the physical appearance of the back of my GFLW if I adopt a weak/neutral left hand grip - as seen in the following birds-eye view capture images where I continuously maintain a GFLW and intact LFFW alignment."

Ahh!  Just getting to your HackMotion graph section for Stenson which might explain the above.

DG

[imperfectgolfer]

Nov 27, 2020 9:41:58 GMT -5 dubiousgolfer said:

Dr Mann

I am just reading through the article and I will be adding my thoughts to this post as I gradually find issues that confuse me.

The first issue I have is this image below:



1. Your forearm seems to have angularly moved upwards in image 2 relative to image 1 (it could be a change in camera position that gives that impression). So that gives the added impression that the clubshaft has moved angularly downwards rather than just by increased ulnar deviation.
2. I cannot bow and radial deviate my lead wrist but I can bow and ulnar deviate excessively which will cause some supination and close the clubface.
3. I think JS must have bowed and excessively ulnar deviated his lead wrist and caused some supination that closed that clubface 13 degrees. Him putting his right finger on the radial bone of his left wrist will stop pronation but not some supination.

I'm not sure about this sentence

"Then, if he maintains a bowed lead wrist all the way between P6 => P7, thereby reaching impact with forward shaft lean (= backwards angulation of the clubshaft relative to the lead forearm due to lead wrist bowing), that means that the forces acting on the club handle are acting in a targetwards direction. " 

Looking at some of the graphs from Choi shows that the right hand force ends up pointing away from the target . The left hand force looks as if its virtually zero or slightly towards the target but I am unsure in what direction the net force is pointing.


DG

I did lift my arm upwards slightly when bowing my lead wrist, but it should not affect the results.

It is easy to supinate the lead forearm if you perform the lead wrist bowing maneuver in ulnar deviation demonstration-experiment, so one should try to avoid that forearm motion.

I cannot see any lead forearm supination happening in JS's demonstration. However, I think that although his clubshaft does not move upwards in a radial direction, I suspect that the ulnar half of his lead hand is rotating more than the radial half and that causes a small degree of lead wrist circumductory roll motion in a clubface-closing manner.

Regarding this sentence - "Then, if he maintains a bowed lead wrist all the way between P6 => P7, thereby reaching impact with forward shaft lean (= backwards angulation of the clubshaft relative to the lead forearm due to lead wrist bowing), that means that the forces acting on the club handle are acting in a targetwards direction." - I am presuming that the trail hand is not applying any forces to the club handle because I am presuming that the golfer is using a TGM swinging technique. However, I will edit that sentence to specify that it is the lead hand.

Jeff.

[dubiousgolfer]

Dr Mann

If Henrik Stenson maintains an intact LFFW/GFLW why is his graph is showing increased flexion when his radial deviation increases in the early downswing (see my arrows in the graph below)? It doesn't correlate with your statement below:

"Note that it is an obvious biomechanical fact that in order for a golfer (who uses a weak-neutral left hand grip) to maintain a GFLW all the way throughout the entire downswing between the P4 position (where the left wrist is radially deviated) to impact (where the left wrist is ulnar deviated), the left wrist angle must continuously change from being significantly dorsiflexed at P4 to becoming far less dorsiflexed (and even slightly palmar flexed) by impact"



Doesn't this mean that HS is actually flexing his lead wrist (while still in extension) as he moves into increased radial deviation in the early downswing?

Imho, I think the shallowing of his swing plane causes a passive increase in the flexion direction.

DG

[dubiousgolfer]

Typo error on this sentence relating to HS's downswing, because I think it should be P5 not P3

"Note that his left wrist is significantly cupped at his P4 position when his left wrist is radially deviated, and also at his P3 position"


I agree and disagree with your statement below 

"A simplistic "belief" expressed by some golf instructors is that Collin Morikawa's clubface will automatically become square by impact if he simply continues to rotate his body counterclockwise to a more open alignment by impact (as can be seen in Collin Morikawa's DTL capture images where his upper torso is definitely more open at P7 compared to P6). However, I believe that it is a fallacy to believe that an extra degree of upper torso rotation can close the clubface (relative to the ball-target line) independently of any counterclockwise rotation of either the lead humerus or the lead forearm."

I think the CCW rotation of either the lead humerus and lead forearm are actively happening in PA#3  but it is not actually being used to close the clubface . The active CCW rotation is just keeping up with a rotation impulse as described in 'Sasho MacKenzie'  passive clubface squaring concept (or even possibly the Ryke effect) .  I won't complicate the issue on this thread but mention why I think this is the case via another thread in the 'Physics of The Golf Swing' category.

DG

[imperfectgolfer]

Nov 27, 2020 18:19:39 GMT -5 dubiousgolfer said:

Dr Mann

If Henrik Stenson maintains an intact LFFW/GFLW why is his graph is showing increased flexion when his radial deviation increases in the early downswing (see my arrows in the graph below)? It doesn't correlate with your statement below:

"Note that it is an obvious biomechanical fact that in order for a golfer (who uses a weak-neutral left hand grip) to maintain a GFLW all the way throughout the entire downswing between the P4 position (where the left wrist is radially deviated) to impact (where the left wrist is ulnar deviated), the left wrist angle must continuously change from being significantly dorsiflexed at P4 to becoming far less dorsiflexed (and even slightly palmar flexed) by impact"



Doesn't this mean that HS is actually flexing his lead wrist (while still in extension) as he moves into increased radial deviation in the early downswing?

Imho, I think the shallowing of his swing plane causes a passive increase in the flexion direction.

DG

That's a good question.

I actually find that increased lead wrist radial deviation phenomenon happening in his HackMotion graph's early downswing very puzzling because I cannot see it actually happening in his capture images.

I don't see increased lead wrist radial deviation happening between image 3 and image 4.

I don't see increased radial deviation of the lead wrist happening between image 1 and image 2.

Increased lead wrist radial deviation is suggestive of a float loading action, but that is not a biomechanical feature of Henrik Stenson's early downswing.

I am basically sceptical of the overall accuracy of HackMotion's graphs.

Jeff.

[dubiousgolfer]

Dr Mann

I am afraid I can't agree wholeheartedly with this statement regarding PP#1 push pressure because of the Choi and Koike right hand force graphs, although it could be that all 10 golfers (used in total) may not be DH'ers. Koike graphs stop data recording at impact but Choi graphs keeps recording in the follow-through and shows that the right hand net force is away from the target through impact.

"A second question arises - can the trailing arm/hand be used to help stabilise the lead wrist through impact so that it does not breakdown (= excessively extend) thereby allowing the clubshaft to bypass the lead arm? I believe that if a golfer avoids "running-out-of-right arm" (which is a situation where the right arm fully straightens and the right wrist fully straightens) during the early followthrough time period, that the right palm can potentially apply a finite amount of stabilising push-pressure against PP#1 (which is located at the base of the lead thumb) and thereby provide an additional element of mechanical stability to the lead wrist that can help prevent it from extending excessively during the early followthrough time period."

DG

[dubiousgolfer]

Dr Mann

I agree that HS is not showing any visible flexion in the early downswing. I don't know whether these HackMotion graphs are an average of many HS swings or just a single instance.

DG

[imperfectgolfer]

Nov 27, 2020 19:57:51 GMT -5 dubiousgolfer said:

Dr Mann

I am afraid I can't agree wholeheartedly with this statement regarding PP#1 push pressure because of the Choi and Koike right hand force graphs, although it could be that all 10 golfers (used in total) may not be DH'ers. Koike graphs stop data recording at impact but Choi graphs keeps recording in the follow-through and shows that the right hand net force is away from the target through impact.

"A second question arises - can the trailing arm/hand be used to help stabilise the lead wrist through impact so that it does not breakdown (= excessively extend) thereby allowing the clubshaft to bypass the lead arm? I believe that if a golfer avoids "running-out-of-right arm" (which is a situation where the right arm fully straightens and the right wrist fully straightens) during the early followthrough time period, that the right palm can potentially apply a finite amount of stabilising push-pressure against PP#1 (which is located at the base of the lead thumb) and thereby provide an additional element of mechanical stability to the lead wrist that can help prevent it from extending excessively during the early followthrough time period."

DG

I doubt that Choi's graphs are on pro golfers who use a bowed lead wrist and who get all the way to P7.4 with a bowed lead wrist + a still markedly bent trailing wrist.

Also, if the right wrist is significantly bent at P7.4, it could be applying a force away from the target in the area of PP#3 in order to prevent clubshaft flipping while it is simultaneously applying a small force towards the target at PP#1. With that thought in mind, I have modified the contents of the following two paragraphs-:

"A second question arises - can the trailing arm/hand be used to help stabilise the lead wrist through impact so that it does not breakdown (= excessively extend) thereby allowing the clubshaft to bypass the lead arm? I believe that if a golfer avoids "running-out-of-right arm" (which is a situation where the right arm fully straightens and the right wrist fully straightens) during the early followthrough time period, that the trailing palm can potentially apply a finite amount of stabilising push-pressure against PP#1 (which is located at the base of the lead thumb) while the trailing hand's 3rd and 4th fingers are potentially applying a force against the club handle that is directed away from the target (secondary to the fact that the trailing wrist continuously maintains its significantly bent-back alignment) - thereby provide an additional element of mechanical stability to the lead wrist that can help prevent it from extending excessively during the early followthrough time period. Note that Kelli Oride's trailing shoulder moves very efficiently downplane between P7 => P7.4 so that she can avoid a "running-out-of-right arm" scenario and that is made more easily possible because of her open shoulder alignment though impact. I cannot prove that Kelli Oride is deriving an additional element of lead wrist mechanical stability between P7 => P7.4 by using her trailing hand/palm in the manner described, but the fact that she does not "run-out-of-right arm" makes this phenomenon more biomechanically achievable.

Now, look again at the capture images of those 3 pro golfers who use a bowed lead wrist technique and a DH-hand release action between P7 => P7.4. Note that they all avoiding a "running-out-of-right arm" scenario and they all have an incompletely straightened right arm and a very bent right wrist at P7.4. I would not be surprised if a scientific research study (using pressure sensors placed at PP#1 and over the aft side of the neighbouring club handle near PP#1 and also over the leading side of the club handle near PP#3 where the trailing hand's 3rd/4th fingers could be pulling back against the club handle in an away from the target direction) demonstrated that they are using their trailing hand/palm to help mechanically stabilise their bowed lead wrist alignment between P7 and P7.4, thereby synergistically helping them to more efficiently perform a DH-hand release action between P7 => P7.4. I strongly suspect that having a bowed lead wrist alignment through impact is more mechanically stable than having a GFLW alignment through impact (between P7 and P7.2) from an anatomical perspective and I would not be surprised to learn that continuously maintaining a bent trailing wrist (as seen in the capture images of those 3 pro golfers) during that early followthrough time period could synergistically increase the degree of mechanical stability of the bowed lead wrist alignment in DHers who use the bowed lead wrist technique."


Jeff.

[dubiousgolfer]

Yes , that makes more sense from a kinetic as well as kinematic perspective. The Choi and Koike left hand graphs show a zero to positive force that increases in the target direction through impact . But I can imagine that left hand positive force is caused by the right hand at PP#1 pressing on the left hand and I think this can be assumed from the sentence below in the Choi article.

"Secondly, the hand grip posture by covering the left thumb by thenar eminence of the right hand leads to the coupling of the grip forces of both hands. Then, the embedded force sensor measurement could possibly underestimate the difference in the hand-grip forces."

DG

[dubiousgolfer]

Dr Mann

When I try and repeat Jon Sinclairs motion in the image below , I can only only close the club if I perform a lead wrist 'flexion and ulnar deviation' circumduction move which tends to also slightly supinate my lead forearm. JS is applying pressure with his right finger on the left forearm to help him perform flexion but it won't prevent supination. Couldn't that be the reason why his clubface closed (a little forearm supination as he 'flexed/ulnar deviated')?



DG

[imperfectgolfer]

DG,

It is indeed possible that he could be supinating his lead forearm slightly during his demonstration when he circumducts his lead wrist. I find it difficult to avoid a small degree of lead forearm supination when I perform a lead wrist circumductory roll motion. I think that the biomechanical reason is related to the fact that if you more actively palmar flex the ulnar half of your wrist (relative to the radial half) to produce a circumductory roll motion at the level of the left wrist joint, it also applies a counterclockwise torque to the lower ulnar bone that will cause it to rotate counterclockwise relative to the lower radial bone.

Jeff.

[dubiousgolfer]

Dr Mann

What happens if the golfer extends his lead wrist at P4 , then retains that extension through release until just before P6 , and then starts moving towards flexion direction as he ulnar deviates? Doesn't this mean clubface opening more while in radial deviation and opening even more as he starts flattening his wrist when moving into ulnar deviation before impact?

DG

[imperfectgolfer]

Jan 21, 2021 22:59:01 GMT -5 dubiousgolfer said:

Dr Mann

What happens if the golfer extends his lead wrist at P4 , then retains that extension through release until just before P6 , and then starts moving towards flexion direction as he ulnar deviates? Doesn't this mean clubface opening more while in radial deviation and opening even more as he starts flattening his wrist when moving into ulnar deviation before impact?

DG

Why should the clubface open more after P6 simply because his lead wrist is becoming less extended - if he does not have a lot of backwards clubshaft angulation away from the target as he nears impact? If he retained his extended lead wrist between P6 => P7, then he would likely have a pre-impact flipping scenario. If he flattened his lead wrist between P6 => P7, then he would likely avoid pre-impact flipping, but that does not mean that his clubface will become more open between P6 => P7.

Jeff.

[dubiousgolfer]

Many thanks Dr Mann

DG