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Post by dubiousgolfer on Oct 25, 2019 6:08:51 GMT -5
Dr Mann I've been reading Tutelman's article below and wondering what your opinions are? I am assuming he is recommending that we 'try' to maintain a constant body torque throughout the downswing even though other forces causes (ie. the inertia of the club) cause our body/arms to decelerate. That we must not 'quit' on the body torque at any point in the downswing. www.tutelman.com/golf/swing/accelerateThru.phpThis is the section that interested me. --------------------- CONSEQUENCES OF ANGULAR DECELERATIONAbove we discussed the angular acceleration of the body. The argument above maintains that, unless you try to accelerate the body's rotation well through impact, you will in fact lose acceleration well before impact. In golf terminology, you will "quit on the shot." This has a number of consequences: Distance actually is lost. This has nothing to do with the clubhead accelerating through the ball, but rather that less acceleration is applied to the clubhead for tens of milliseconds before impact. The clubhead is deprived of some of the accleration it would have had, in order to build up speed at impact. And clubhead speed at impact is what really matters for distance. The left wrist is cupped, rather than the proper flat or even bowed left wrist. We know that a bowed wrist at impact (or a flat wrist at the very least) is desirable for a solid hit. A cupped wrist, on the other hand, is associated with lost clubhead speed, fat or thin shots, or too-high balloon shots. It is also likely to point the clubface to the left, resulting in a pull or even a pull-hook. (Think about it this way: if the swing plane were perfectly vertical, then a cupped left wrist would add loft. Since the swing plane is not vertical but tilted, some of that "loft" turns into a left-facing angle.) --------------------------------------------- Then Tutelman proceeded to use some swing simulation software called 'SwingPerfect' to apply 'Body Torque' during various phases of the downswing and produced the diagrams below . I have addded some of his comments further below. ----------------------------------------- If you deprive the downswing of body torque by quitting on it, you lose clubhead speed -- and, obviously, distance. Not only that: the torque late in the downswing (the torque you lose when you quit) is more important than torque early in the downswing. How do we know? Because we still lost 3mph of clubhead speed (about 9 yards) in the third calculation, where the total torque-seconds were the same as the no-quit swing; the torque was larger early in the downswing and reduced during the "quit" at the end. Loss of body torque late in the downswing will indeed turn a bowed wrist (good!) into a cupped wrist (bad!). BOTTOM LINE
"Accelerate though the ball" is an excellent swing key, for every shot from a drive to a putt. But it is better expressed as "rotate your body through the ball" (or perhaps "accelerate moving your hands beyond the ball"), because it is body rotation or "turning the triangle" where acceleration through the ball is beneficial. Consciously accelerating the clubhead through the ball (especially if you do it with the hands, wrists, or forearms) will probably do more harm than good ------------------------ DG
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Post by imperfectgolfer on Oct 25, 2019 9:17:41 GMT -5
Although DT is very knowledgeable regarding golf swing physics, he is very informed regarding TGM mechanics and golf biomechanics. His claim that the body and arm triangle must be accelerating through impact has zero merit. Here is Jamie Sadlowski's 3-D graph. Note that his pelvic, upper torso and left arm angular velocity is slowing down pre-impact - although clubhead speed is not slowing down as a result of that fact. A TGM swinger powers the golf swing via the release of PA#4 => PA#2 and the left arm must slow down in the later downswing to allow a golfer to successfully complete the release of PA#2. Although the left arm must slow down between P6.5 and impact, there must be enough left arm speed retained between P7 and P7.2 (or P7.4) to allow the left arm to have the same angular velocity as the clubshaft during the early followthrough if the golfer wants to be a DHer. Flipping post-impact will occur if left arm speed is too slow between P7 and P7.2. Flipping pre-impact is a gross swing fault due to excessive left arm slowing in the later downswing.
I do not trust DT's SwingPerfect program because we have no knowledge about how it measures "body torque" from a TGM perspective. Jeff.
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Post by syllogist on Oct 25, 2019 9:34:38 GMT -5
Dr. Mann,
I read through DT's article and got the impression that continuous body acceleration was recommended as more of a "psychological factor" in that without the intent to continue to accelerate, one could prematurely "quit." I'm sure that DT understands deceleration of proximal segments as distal segments accelerate.
However, by assuming in his model that premature body deceleration results in the clubhead passing the hands before impact, I don't think that DT accounted for the length of time that the left arm remains abducted during torso rotation or that one can delay the "unfolding" of the arms and wrists without continuous torso acceleration.
His recommendation is probably more of a swing thought for a struggling golfer.
S
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Post by imperfectgolfer on Oct 25, 2019 9:57:28 GMT -5
Here is another reason why I have zero trust in DT's SwingPerfect program. Look at the shape of the hand arc path in these images.
Look at how circular the hand arc path is and it looks like David Toms' hand arc path in the following capture image.
DT loses his lag early - compared to many pro golfers like Dustin Johnson and Cameron Champ.
Here is the hand arc path of Dustin Johnson.
Dustin Johnson's driver and wedge hand arc paths.
Note that DJ's driver swing's hand arc path has a very "tight" turn between P5.5 and P6.2.
I strongly suspect that DT has not done any calculations to take into account the different hand arc paths of different pro golfers.
Jeff.
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Post by dubiousgolfer on Oct 25, 2019 18:58:58 GMT -5
Dr Mann I'm finding that JS graph confusing . It definitely shows that the pelvis, upper torso and left arm angular velocity is slowing down pre-impact but how can one assess if JS is actually applying positive upper torso torque (anti-clockwise from a face-on view) after P5.5 , while at the same time experiencing an increasing negative torque by the changing MOI (Moment of Inertia) of the arm/club unit? Could it be analagous to pushing a car with a constant force while somehow the friction between the road surface and wheels get progressively larger? The car decelerates while you are still pushing with a constant force. So the graph may show JS's upper torso decelerating but how can one actually confirm whether JS is using some musculature effort to apply upper body torque? Wouldn't it be useful to conduct electromyography research on the muscles of the upper torso throughout the downswing? DG PS. Have done a google search and found a recent article that looks interesting . www.ncbi.nlm.nih.gov/pmc/articles/PMC4925984/Unfortunately , the sample size was small and doesn't show how large the muscular contractions were during the golf forward swing. But they did show a muscle firing sequencing which I've never seen before. It seems to show contraction of the Left External Oblique for most of the downswing.
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Post by imperfectgolfer on Oct 25, 2019 20:47:45 GMT -5
Dr Mann I'm finding that JS graph confusing . It definitely shows that the pelvis, upper torso and left arm angular velocity is slowing down pre-impact but how can one assess if JS is actually applying positive upper torso torque (anti-clockwise from a face-on view) after P5.5 , while at the same time experiencing an increasing negative torque by the changing MOI (Moment of Inertia) of the arm/club unit? Could it be analagous to pushing a car with a constant force while somehow the friction between the road surface and wheels get progressively larger? The car decelerates while you are still pushing with a constant force. So the graph may show JS's upper torso decelerating but how can one actually confirm whether JS is using some musculature effort to apply upper body torque? Wouldn't it be useful to conduct electromyography research on the muscles of the upper torso throughout the downswing? DG What does it mean to infer that a golfer is still applying upper torso musculature torque if the upper torso actually slows down after P5.5? On what basis could you make that inference? EMG studies are crude and cannot clearly differentiate isometric contraction from isotonic contraction. Have you any reason to believe that there is some impedance to upper torso rotation in the later downswing that causes a slowing down of the angular velocity of upper torso rotation and have you any reason to believe that a golfer must therefore apply extra rotary torque to the upper torso to overcome that impedance? Also, what would the potential benefit be - do you think that it would increase the efficiency of release of PA#4 and PA#2 or increase clubhead speed by some other mechanism? Jeff.
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Post by dubiousgolfer on Oct 26, 2019 6:53:03 GMT -5
Dr Mann
What about the increased tension in the clubshaft? Won't the tension at the handle pull against the movement of the hands along its path? The hands in turn will pull against the lead arm and increase its tension. The increased tension in the lead arm pulls against the shoulder girdle and possibly other muscles that stabilise the shoulder girdle against the thoracic wall. Won't this also cause impedance of any rotation of the upper thoracic against the contraction of the left abdominal obliques?
Won't the potential benefit of overcoming that impedance limit loss of hand speed along its path because hand speed as well as hand path dictates the timing and degree of PA#2 release?
DG
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Post by imperfectgolfer on Oct 26, 2019 9:06:26 GMT -5
Dr Mann What about the increased tension in the clubshaft? Won't the tension at the handle pull against the movement of the hands along its path? The hands in turn will pull against the lead arm and increase its tension. The increased tension in the lead arm pulls against the shoulder girdle and possibly other muscles that stabilise the shoulder girdle against the thoracic wall. Won't this also cause impedance of any rotation of the upper thoracic against the contraction of the left abdominal obliques? Won't the potential benefit of overcoming that impedance limit loss of hand speed along its path because hand speed as well as hand path dictates the timing and degree of PA#2 release? DG I am not aware of "feeling" any increased tension in the club handle that restricts forward motion of the hands in the later downswing and early followthrough (even if the peripheral clubshaft is bent forward a few cms relative to the proximal clubshaft). I have zero sympathy for your line of reasoning that there is impedance to upper torso rotation in the later downswing due to tension in the club handle. Jeff.
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Post by syllogist on Oct 26, 2019 9:12:01 GMT -5
Dr. Mann, I think that the skilled golfer only intends and senses acceleration. However, when it comes to being cognitively aware that his chest needs to be approx. N degrees open by impact, he likely utilizes rotational force long enough such that it will happen, despite the fact that he will experience a decrease in rotational velocity before impact. I know that you're not impressed with Athletic Motion Golf's analyses of the swing but take a look at this production and draw your own conclusion about why the skilled amateur, whose swing in many respects is similar to the professional's, is not in the league of the professional. What I note is that the amateur's "cognitive picture of a swing" tells him that his left arm needs to accelerate off his chest (PA #4 as you would call it) sooner than it should. It hasn't occurred to him that it might be better to have the left arm somewhat "across" the chest even at impact. www.youtube.com/watch?v=PHRkgBIdoFYAs for your comment about David Toms' hand path - I think he lacks sufficient reduction in radius of the hand path primarily because his maintenance of right arm bend is longer than usual. He might be the tour's anomaly. I believe that the main differentiator of clubhead speed on the tour, notwithstanding stature, is rotational velocity of the torso. S
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Post by imperfectgolfer on Oct 26, 2019 9:51:07 GMT -5
S, You wrote-: " What I note is that the amateur's "cognitive picture of a swing" tells him that his left arm needs to accelerate off his chest (PA #4 as you would call it) sooner than it should. It hasn't occurred to him that it might be better to have the left arm somewhat "across" the chest even at impact." I disagree with your reasoning. It is true that golfers who have more open shoulders at impact will likely have the left arm more closely adducted against the left upper chest wall than golfers who have their shoulders parallel to the ball-target line at impact. However, I don't believe that it has any connection with the timing and efficiency of release of PA#4. Here are two pro golfers who both release PA#4 very efficiently in their driver swings, but have different upper torso alignments at impact. Phil Mickelson
Note that he has square shoulders at impact and his lead arm is not closely adducted against his chest wall at impact.
Cameron Champ
Note that his lead arm is less abducted away from his chest wall at impact.
An open torso at impact is very advantageous in terms of an increased biomechanical ability to drive-hold because it allows the rear shoulder to get further forward and prevent a "running-out-of-right arm" scenario with respect to the rear arm.
You wrote regarding David Toms swing-: "As for your comment about David Toms' hand path - I think he lacks sufficient reduction in radius of the hand path primarily because his maintenance of right arm bend is longer than usual".
I disagree!
Here are the hand arc paths of Dustin Johnson and Cameron Champ.
Dustin Johnson
Cameron Champ
Both of those pro golfers retain their bent right elbow to P5.5 - like David Toms - but they both adduct their right arms much faster than DT so that they get their hands well below waist level at P5.5, while DT has a very slow speed of right arm adduction between P4 and P5.5 - see image 3 below where his hands are still above waist level.
Jeff.
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Post by dubiousgolfer on Oct 26, 2019 21:17:51 GMT -5
Dr Mann What about the increased tension in the clubshaft? Won't the tension at the handle pull against the movement of the hands along its path? The hands in turn will pull against the lead arm and increase its tension. The increased tension in the lead arm pulls against the shoulder girdle and possibly other muscles that stabilise the shoulder girdle against the thoracic wall. Won't this also cause impedance of any rotation of the upper thoracic against the contraction of the left abdominal obliques? Won't the potential benefit of overcoming that impedance limit loss of hand speed along its path because hand speed as well as hand path dictates the timing and degree of PA#2 release? DG I am not aware of "feeling" any increased tension in the club handle that restricts forward motion of the hands in the later downswing and early followthrough (even if the peripheral clubshaft is bent forward a few cms relative to the proximal clubshaft). I have zero sympathy for your line of reasoning that there is impedance to upper torso rotation in the later downswing due to tension in the club handle. Jeff. Dr Mann This is what Rod White says on Tutelmans website (is his reasoning flawed?) --------------------------- How is the energy transferred? We have discussed the golf swing in terms of the conservation of energy and momentum, and showed that the energy is transferred to the club as the swing unfolds, but what actually happens – where are the forces that make this happen? The figure shows a ‘stroboscopic’ view of the golf swing. Have a close look at the direction of the clubhead midway through the swing – this is indicated approximately by the red arrow. Now look where the hands move at the same time – the blue arrow: in a different direction! Obviously the hands and clubhead cannot continue to move in different directions, they are restrained by the fixed length of the shaft. The diverging directions of the club and hands results in a large tension in the shaft. The tension pulls against the club head causing it to accelerate, and pulls against the hands causing them to decelerate. It is the differing directions of the hands and club that are ultimately responsible for the energy transfer. In a professional golfer's swing, the tension peaks above 500 N (50 kg equivalent, or over 100 pounds). During this phase of the swing the rate at which energy is transferred to the club peaks at about 5 kW (or almost 7 horsepower). -------------- DG
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Post by imperfectgolfer on Oct 27, 2019 0:21:01 GMT -5
I have no doubt that the clubshaft is under tension before P5.5 (at the start of the release of PA#2), but that phenomenon does not exist in the later downswing after the release of PA#2 (which causes the peripheral clubshaft to be bent forward relative to the proximal clubshaft).
Jeff.
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Post by syllogist on Oct 27, 2019 5:43:52 GMT -5
Dr. Mann,
David Toms, with a lengthy 90 degree right arm bend, comes into delivery with a "high pointing" right forearm. The others you used for comparison have more forward bend and thus don't have the high pointing forearm. Toms procedure is why, from a face-on view, the hand path appears circular and not nearly as vertical as the others.
I think that the Athletic Motion production is a fair assessment for the comparative iron swings except that, to get a more complete picture, the timing of left arm adduction to abduction should be covered with the extent of chest rotation. The two work in tandem. Driving swings can generally be analyzed in the same context except that the ball is effectively more forward in the stance and angle of attack is shallower. Champ is an interesting one to view as the trajectory of his stock drive is very low from a forward leaning shaft. It would be interesting to see how he changes his swing to hit a higher trajectory shot.
S
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Post by dubiousgolfer on Oct 27, 2019 7:38:09 GMT -5
Dr. Mann, David Toms, with a lengthy 90 degree right arm bend, comes into delivery with a "high pointing" right forearm. The others you used for comparison have more forward bend and thus don't have the high pointing forearm. Toms procedure is why, from a face-on view, the hand path appears circular and not nearly as vertical as the others. I think that the Athletic Motion production is a fair assessment for the comparative iron swings except that, to get a more complete picture, the timing of left arm adduction to abduction should be covered with the extent of chest rotation. The two work in tandem. Driving swings can generally be analyzed in the same context except that the ball is effectively more forward in the stance and angle of attack is shallower. Champ is an interesting one to view as the trajectory of his stock drive is very low from a forward leaning shaft. It would be interesting to see how he changes his swing to hit a higher trajectory shot. S Hi S Are you talking about the affects of 'Parallax' ? Check this thread out that I previously raised a long time ago: newtongolfinstitute.proboards.com/thread/584/endless-belt-aiming-point-confusionImho , the only way to determine the true hand path (and their instantaneous radius of curvature) would be from a reference point normal to the lead arm swing plane at every moment in time during the downswing. DG PS. I need to review this again because something does not make sense to me.
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Post by syllogist on Oct 27, 2019 8:05:07 GMT -5
Hi DG,
It's not from parallax. From a face-on view, the degree of curvature for release can be reasonably assessed, about which Dr. Mann made a reasonable comment. I was pointing out why Toms' downswing was more of a "U" than a "V."
S
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