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Post by dubiousgolfer on May 30, 2017 18:49:04 GMT -5
Dr Mann With reference to SMK's analysis summarised by this diagram below I am assuming that his claim is that by doing this 'move', less muscular torque is required to square the clubface during delivery phase. But what if a person has weak forearms and wrists? Won't this underplane move, where you 'palmar flex' the left wrist, also tend to pronate the left forearm more while its still 'on plane' (and disrupt the LFFW even more)? I don't see the point in even contemplating this 'extra move' just to negate any difficulty in squaring the clubface via the rotation of the forearms during delivery. Further , if PA3 is no longer a valid Power Accumulator due to the fact that the rate of closure for a drive-hold release is not as large as a 'non-optimal' full roll release, then I am assuming that one doesn't need much muscular forearm torque to square the clubface. So , for the recreational golfer, is there really any point in trying to utilise SMK's underplane move above?
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Post by imperfectgolfer on May 30, 2017 19:48:22 GMT -5
Dr Mann With reference to SMK's analysis summarised by this diagram below I am assuming that his claim is that by doing this 'move', less muscular torque is required to square the clubface during delivery phase. But what if a person has weak forearms and wrists? Won't this underplane move, where you 'palmar flex' the left wrist, also tend to pronate the left forearm more while its still 'on plane' (and disrupt the LFFW even more)? I don't see the point in even contemplating this 'extra move' just to negate any difficulty in squaring the clubface via the rotation of the forearms during delivery. Further , if PA3 is no longer a valid Power Accumulator due to the fact that the rate of closure for a drive-hold release is not as large as a 'non-optimal' full roll release, then I am assuming that one doesn't need much muscular forearm torque to square the clubface. So , for the recreational golfer, is there really any point in trying to utilise SMK's underplane move above? I think that SMK's explanation makes no sense because i) he wrongly assumes in his calculations of torque forces that the entire left arm rotates as an unit when in reality it is only the left forearm that rotates and ii) he assumes that the rotation of the LFFW happens in the mid-downswing and early phase of the late downswing when it mainly happens after P6.5 - after the release of PA#2 (which markedly decreases the accumulator #3 angle before PA#3 is released). I criticized SMK's thinking in this thread - newtongolfinstitute.proboards.com/thread/556/chris-sashso-mackenzie-video-release. Thirdly, the amount of left forearm supinatory power needed in a PA#3 release action is inversely proportional to left hand grip strength, which means that golfers (like Jamie Sadlowski) who use a very strong left hand grip do not even need to supinate their left forearm pre-impact because they do not perform a PA#3 release action in the late downswing between P6.5 and impact. SMK never even discusses that "issue". When a golfer shallows the clubshaft in the P4 => P5.5 time period, they do not necessarily perform an "underplane" move relative to the ball-target line (although the LFFW is obviously "underplane" relative to the left upper arm). It is possible to keep the clubshaft continuously "on-plane" during a clubshaft shallowing action - as I explained in this short review paper at perfectgolfswingreview.net/VP6.html . Golfers who prefer to get their hands/clubshaft down to the elbow plane (or hand plane) by P6 and who keep their clubshaft on the elbow (or hand plane) between P6 and impact while maintaining a vertical left arm (like Sergio Garcia and Ben Hogan) need to perform a clubshaft shallowing action during their early-mid downswing - but it has nothing to do with the idea of reducing the amount of torque needed to release PA#3. Also, there is no reason to palmar flex the left wrist during a clubshaft shallowing action that happens between P4 and P5.5, and one should optimally maintain an intact LFFW/GFLW and an "on-plane" clubshaft. You wrote-: " Further , if PA3 is no longer a valid Power Accumulator due to the fact that the rate of closure for a drive-hold release is not as large as a 'non-optimal' full roll release, then I am assuming that one doesn't need much muscular forearm torque to square the clubface." I think that you are making many mistakes in that sentence. First of all, a PA#3 release action only refers to the pre-impact phase between P6 and impact and it has nothing to do with the post-impact phase between impact and P7.2 so DHers have to use the same amount of left forearm supination as non-DHers during their PA#3 release action (presuming that they both use the same strength of left hand grip) and they therefore need to use the same amount of left forearm supinatory torque. SMK doesn't seem to understand that one doesn't really need much left forearm supinatory torque during a PA#3 release action because of two supplementary factors (that he never discusses) - i) the positive influence of the RYKE effect and ii) the role of the right forearm in synergistically inducing a PA#3 release action via push-pressure being applied by the right palm against PP#1 over the base of the left thumb during the right forearm paddlewheeling action between P6 and impact. By the way, I regard the PA#3 release phenomenon as a clubface-squaring phenomenon, and not a swing power generation phenomenon (which is why I no longer think of a PA#3 release action as being a source of swing power that can potentially increase clubhead speed at impact). I discussed that particular issue in this short review paper - perfectgolfswingreview.net/VP10.htmlJeff.
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Post by dubiousgolfer on May 30, 2017 20:26:17 GMT -5
Many thanks again for your detailed reply.
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Post by dubiousgolfer on Apr 20, 2020 22:27:59 GMT -5
After seeing that SMK/Como video again I re-read his research article and now I am completely confused about why SMK said that a golfer isn't strong enough to supinate their left forearm 90 degrees from P6 to P7 in .014 secs. 1. In his research article and golfing model (which included limitations in human muscle/joint capabilities) he also increased the left forearm torque capability to take into account the influence of a torque created by a 'right arm'. 2.He had a SIM3 scenario where the golfers shaft and hand plane were 'On Plane' and then the various torque generators (including muscular forearm supination) were optimised to square the clubface by impact . In fact the clubhead speed was around 44.1 m/s which was 22% higher compared to his passive squaring scenario (ie. clubshaft below hand plane) of 36.2 m/s. So if SIM3 was a viable scenario within the limitations of his model's human capability , it makes no sense that he should imply otherwise on that video. With that 22% increase in clubhead speed, I cannot understand why PA#3 cannot be deemed to be a power producer rather than just a club squaring accumulator? Dr Mann You have written an article about why you no longer accept PA#3 as a power accumulator below but I cannot see any evidence to back up that claim even though you regard the 'Drive Hold' hand release as optimal. If a golfer does not wish to use a drive-hold hand release and wishes to maximise his clubhead speed , why not use an active muscular PA#3 ? www.perfectgolfswingreview.net/VP10.htmlDG
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Post by imperfectgolfer on Apr 20, 2020 23:32:58 GMT -5
After seeing that SMK/Como video again I re-read his research article and now I am completely confused about why SMK said that a golfer isn't strong enough to supinate their left forearm 90 degrees from P6 to P7 in .014 secs. 1. In his research article and golfing model (which included limitations in human muscle/joint capabilities) he also increased the left forearm torque capability to take into account the influence of a torque created by a 'right arm'. 2.He had a SIM3 scenario where the golfers shaft and hand plane were 'On Plane' and then the various torque generators (including muscular forearm supination) were optimised to square the clubface by impact . In fact the clubhead speed was around 44.1 m/s which was 22% higher compared to his passive squaring scenario (ie. clubshaft below hand plane) of 36.2 m/s. So if SIM3 was a viable scenario within the limitations of his model's human capability , it makes no sense that he should imply otherwise on that video. With that 22% increase in clubhead speed, I cannot understand why PA#3 cannot be deemed to be a power producer rather than just a club squaring accumulator? Dr Mann You have written an article about why you no longer accept PA#3 as a power accumulator below but I cannot see any evidence to back up that claim even though you regard the 'Drive Hold' hand release as optimal. If a golfer does not wish to use a drive-hold hand release and wishes to maximise his clubhead speed , why not use an active muscular PA#3 ? www.perfectgolfswingreview.net/VP10.htmlDG Do you really believe that adding forearm muscular torque to release PA#3 can increase clubhead speed by 22%? How is that possible? Here is Phil Mickelson's PA#3 release action.
Image 2 is at P6.7 where he has not yet started to release PA#3. Do you really believe that PM is increasing his clubhead speed by 22% by successfully releasing PA#3 by impact.
Jeff.
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Post by dubiousgolfer on Apr 21, 2020 13:00:38 GMT -5
Dr Mann
PM is a good example of the SIM1 (that looks like a SIM3) golfer in SMK's research article and he doesn't seem to be using much muscular forearm supination to square the clubface from P6.7 (although he does have a 'Roller' release hand action).
Can one discount that there could be instantaneously small differences between the hand and clubshaft plane (too small to easily visualise) happening through PM's downswing, where the clubshaft COM is always slightly below the hand plane? This is where the clubs COM is always trying to 'catch up' with the slightly steeper hand plane. The hand plane could be getting slightly steeper than the clubshaft plane by continuous imperceptible small amounts giving the impression that shaft/hand path are on the same plane?
If true then there is a continuous dynamic 'MOF' being applied to the clubs COM during the downswing providing an angular impulse all the way to P6.7 that could be used to square the clubface when the MOI of the hand/club around the longitudinal axis of the lead forearm is small .
The formula for angular momentum (L) is:
L = Iw (Moment Of Inertia x angular velocity)
L/I = w (therefore even a small amount of 'angular momentum impulse' WITH an even smaller MOI, can create a high rate of supination to square the clubface).
The Ryke effect is different and requires some unexplained transverse net force (towards the golfers body) to invoke, so is it more realistic than the above theory?
Kevin Ryke's model looks impressive at squaring the clubface when the angular velocity of the peripheral arm is small but I'd like to see how it would work at higher angular velocities comparable to that of a real golfer.
I am also doubtful how a heel-toe rotation of the club caused by musculature forearm rotation (ie. SIM3 in SMKs article) can increase the clubhead speed by 22% but I know from painful experience that physics/kinetics can be completely non-intuitive. I've asked SMK this question and hope he can reply back in a way that I might understand.
DG
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Post by dubiousgolfer on Apr 22, 2020 20:19:48 GMT -5
I think one can discount my post above about PM after seeing this slow motion video.
I don't have the software to analyse hand and club paths but I think his clubshaft plane is above his right hand path plane from P4-P5.5 (so there are no continuous small imperceptible SMK type 'passive torques' being applied in his downswing).
What I did find interesting was the lagging shaft bend one can see away from the target line at P5.5 (look at the left image at 1:33) and becomes even more pronounced when he is at P6 (see left image at 1:34). I think that shaft bend actually starts just before P5.5 and then dissipates by P7
If I'm not mistaken , I think that must mean he is applying a positive torque component from P5.5-P6 at the grip end outwards towards the left towards the ball target line. He doesn't seem to be creating any visible lagging shaft bend within the shaft plane from P4-P5.5.
It's difficult to perceive whether his right arm/hand can assist with any positive torque so it must be the straightening of his left elbow. So is PM applying just enough force with his left 'arm/hand' to support his LFFW (although he is a leftie) to keep it on plane?
DG
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Post by dubiousgolfer on Apr 22, 2020 21:38:15 GMT -5
Here is a close up slow mo view of Adam Scotts swing (especially his hands).
Look at 3:24 where the back of his left wrist is almost facing the ball-target line at P6.7 (probably P6.8).
I can imagine the club has a very small MOI around the longitudinal axis of his left arm and that it wouldn't take much musculature effort to square the clubface.
SMKs assertions seem very doubtful about AS applying downward forces and actually deploying a 'passive torque' effect. He will need to provide more evidence to prove his opinion.
DG
PS. Looks like the hand images were taken from a different camera angle so maybe AS's hands weren't facing the target line as much as it seems.
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Post by dubiousgolfer on May 13, 2020 18:20:09 GMT -5
Just found this AMG golf video below: I'm assuming they are not in agreement with SMK's passive 'positive beta torque' concept and that a golfer can quite easily override its effect with a 'negative beta torque' caused by right arm adduction and pitch elbow action (which can keep the clubshaft 'On Plane' with hand path or even shallow it below the hand path while still 'On Plane'). I wonder why SMK never even contemplated the other torques that could be applied by the golfer during their shallowing actions before making those videos with Chris Como? Why did he assume that the golf downswing biomechanics (especially the kinetics aspect) was similar to his one-armed swing? So this is confusing for someone like me who wishes to understand the kinetics involved and I still have questions that cannot be confirmed without further supporting evidence: 1. Is there some SMK primed 'positive beta torque' ready to 'kick into action' and generate some angular momentum from P5.5 (after any 'negative beta torque' caused by 'right arm adduction/pitch elbow has dissipated)? If yes, we should see some gradual increase in rate of lead arm supination from P5.5 to P6.5 and then a rapid increase in its rate as the MOI of the club (around the lead arm longitudinal axis) gets smaller to conserve the angular momentum created earlier from P5.5 (ie. PA#3 release). 2. If there isn't a primed 'positive beta torque' waiting to kick in from P5.5 , can a golfer with a neutral grip still have time to use musculature forearm supination to square the club from P6.5 with a large PA3 angle? 3. If there isn't a primed 'positive beta torque' waiting to kick in from P5.5 , would only a golfer (neutral grip) with a small/moderate PA3 angle be able to square the clubface from P6.5 using musculature forearm supination? 4. For a golfer with a large PA3 angle - If there is a primed 'positive beta torque' waiting to kick in and help square the clubface , would it be more advantageous than a musculature forearm supination action to perform a DH hand release action? 5. For a golfer with a small/moderate PA3 angle - if there is a primed 'positive beta torque' waiting to kick in and help square the clubface, would it be more advantageous than a musculature forearm supination action to perform a DH hand release action? When I look at Phil Cheetham's graph below it does seem to match point 1 above without considering the Ryke effect to explain PA#3 release. But imho, there isn't enough evidence to prove exactly what is going on from the kinetics perspective. DG
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Post by dubiousgolfer on May 14, 2020 11:27:15 GMT -5
Thought I'd just add some maths : MOI of the club around the lead arm axis could be approximated as I = mr 2 ......(1) m=mass of club, r is the distance from the lead arm axis to the COM of the club. Lets say the angular momentum created by SMK's passive torque = L = Iw .........(2) (where w = angular velocity of the club around the lead arm axis- similar to angular velocity of lead forearm supination) Substituting (1) into (2) L = mr 2w = wmr 2
Thereforew = L/mr 2The angular momentum L is considered conserved and constant , m is also a constant , therefore L/m can be considered a constant which we will call 'C' w= C/r 2The general shape of a graph representing w=C/r 2 is shown below where 'w' is the y-axis , while 'r' is in the x-axis. Its easier to see on the left side of the graph as the modulus (absolute value) of 'r' reduces (ie. PA2 angle increases and the clubs COM gets closer with the lead arm axis), the angular velocity 'w' increases rapidly. That graph shape is similar to the Phil Cheetham blue lined graph in previous post above. DG
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