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Post by imperfectgolfer on Oct 14, 2019 23:53:54 GMT -5
Watch this BeBetterGolf video that Brendon DeVore did with Mike Malaska. In that video, Mike Malaska wrongheadedly claims that Brendon's clubface is square to the clubhead arc from waist-high (at P6) to waist-high (at P8). That's obviously impossible because Brendon uses a neutral left hand grip, which means that he has to use a PA#3 release action (which is biomechanically secondary to left forearm supination) in order to square his clubface in his late downswing. Here are capture images from the video.
Image 1 shows Brendon at the P6 position. The red arrow is pointing at his clubface - which is open to the clubhead arc and where the toe of his clubhead is pointing upwards.
Image 2 is at P6.5 where the clubface is still somehwat open to the clubhead arc, but it is closing secondary to the release of PA#3. It is stupefying to realize that both MM and BD are totally TGM-illiterate and totally uninformed about the "real life" facts on the biomechanics/mechanics of clubface closure during the late downswing!!! As a reminder, here is Phil Cheetham's 3-D graph (from his study of 92 pro golfers) showing how the clubface closes in the late downswing secondary to the release of PA#3.
Note how fast the clubface is closing after the vertical violet arrow (representing the release of PA#3) and note that it is due to left forearm supination. Finally, here are capture images of Mike Malaska's "real life" golf swing action. Downswing Image 2 is at his P6 position. Note that his clubface is wide open to the clubhead arc and the toe of his clubhead is facing straight upwards.
Note that the back of his left hand is parallel to the ball-target line at P6 (image 2) and perpendicular to the ball-target line at impact (image 3) and that means that the clubface rotated ~90 degrees between P6 and impact - and that is entirely due to left forearm supination because there has been virtually no external rotation of his left humerus happening between P6 and impact.
Followthrough Mike is using his "right arm throw" action to flip the clubshaft passed his left arm causing left wrist breakdown.
Note that the clubface is markedly closed to his clubhead arc in image 3 and he is not keeping the clubface square to his clubhead arc all the way to the P8 position. The clubface is rolling closed (relative to his clubhead arc) during his followthrough because the left wrist is circumducting during the left wrist breakdown process.
Jeff.
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Post by imperfectgolfer on Oct 20, 2019 10:22:36 GMT -5
More Malaska stupidity!!!
Consider the following BeBetterGolf video.
Brendon asks MM what is responsible for generating his swing power.
At the 1:29 minute time point of the video, MM replies by stating that he produces swing power after he gets to the P5.5 position by straightening his left leg and pushing his left hip joint straight back ("pushing the left hip out of the way"). MM states that this pelvic motion (where the left hip joint moves further away from the ball-target line) is his "gas pedal" which causes the clubhead to accelerate into impact.
How is this possible? MM (as per usual) does not explain the causal connection between that later downswing's pelvic motion and clubhead acceleration. I believe that it is only possible to accelerate the clubhead in the late downswing via the phenomenon of parametric acceleration (which involves a shortening of the hub path), but that hub path radius shortening phenomenon can only produce a maximum of a 5% increase in clubhead speed - according to the following graph from Miura's research study.
Note that clubhead speed only increases 5% over the base value due to the phenomenon of parametric acceleration (caused by the upward pull of the hub path near impact).
MM may be "feeling" the clubhead accelerating fast after P5.5, but that is simply due to the sequential release of PA#4 => PA#2, and it is very important to realize that the swing power factors causing the release of PA#4 happen before P5.5. MM likens the clubhead acceleration that he "feels" happening in the late downswing to the "snapping of a towel". However, he does not expand on this analogy where the hand motion causing a towel to snap is a sudden pulling back of the hands holding the towel. How does this hand towel-snapping action relate to a full golf swing action performed by a pro golfer?
At the 3:43 minute time point of the video, Brendon and MM discuss this phenomenon further, and MM states that the left hip joint moving backwards away from the ball-target line and the club starting to release outwards (representing the release of PA#2) are due to parallel force vectors, and MM wrongheadedly claims that there is a causal connection between the two phenomena. How is this possible? How can the "clearing of the left hip" cause the release of PA#2?
At the 5:15 minute time point of the video, MM claims that "rotation is an effect and not a cause". MM wrongheadedly claims that the "body only understands straight line forces" and that the pelvis rotates during a full golf swing because in the backswing MM pushes his right joint back away from the ball-target line and during the later downswing he pushes his left joint back away from the ball-target line. MM totally ignores the "true" causal factors causing an active pelvic rotation during the downswing - i) muscular contraction of the right-sided lateral pelvic rotator muscles and ii) horizontal GRMs produced by pushing against the ground under the feet (as described by Dr. Scott Lynch in a previous BeBetterGolf video).
At the 7:40 minute time point of the video. MM quotes Jack Nicklaus and he claims that JN stated that he allows the the "weight of the club to pull him through into the followthrough". So, MM is presumably asserting that the body rotation happening between impact and P9+ is due to the "weight of the club pulling him through to his full finish position".
Here again are capture images of MM's personal followthrough action.
Note how the clubshaft has outraced his left arm causing "left wrist breakdown" (image 3).
Do you really believe that any torso rotation (pelvis and upper body) happening between impact and the end of the followthrough is due to the "club pulling the body" around in its circular arced motion?
MM totally ignores the muscular forces causing an upper torso rotation in the late downswing and continuing into the followthrough.
Here is Rory McIlroy's 3-D graph.
Note Rory's fast upper torso rotation (green graph) happening in the early followthrough. Do you really believe that it is due to the "weight of the club" pulling his upper torso around? The MM-groupies may believe this type of irrational claim, but they are routinely capable of believing "anything" MM claims!!!
Jeff.
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Post by syllogist on Oct 20, 2019 11:10:57 GMT -5
Dr. Mann,
I agree. Most assertions that I come across cannot stand up to scrutiny.
By the way, "parametric acceleration" was more of a mathematical exercise by the researcher. It would be applicable to speeding the release of the club if the hands were able to abruptly and briskly change direction. If I recall, Miura used a directional change of "hand path" equal to 90 degrees to come up with a 6% gain. In his study, he admitted that hand path is mainly "horizontal," implying that actual gains would be much smaller, but did note that he observed an "inward pull" from all his study participants.
S
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Post by imperfectgolfer on Oct 20, 2019 20:58:46 GMT -5
S, You wrote-: " If I recall, Miura used a directional change of "hand path" equal to 90 degrees to come up with a 6% gain." Look again at this diagram from Miura's research study. From my understanding of his research study, the hand arc path (hub path) nearing impact is relatively horizontal and he then applied an upward pull generated by the velocity actuator on the club handle that caused the hand arc path to become tilted more upwards near impact (depending on the speed of upward motion of the velocity actuator).
Here is another diagram showing the effect of the upward pull of the velocity actuator on the hand arc path near impact.
Note that the upward pull causes the hand arc path (green path), and therefore clubhead path, to be slightly elevated near impact (red path), and he estimated that it could potentially increase clubhead speed by up to 5% (presuming an unchanged smash factor). He did not imply that "it would be applicable to speeding the release of the club if the hands were able to abruptly and briskly change direction" because the hands cannot abruptly change direction as they approach impact.
Jeff.
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Post by utahgolfer on Oct 21, 2019 1:34:55 GMT -5
Jeff, I had an interesting discussion regarding MM's no rotation video with my teaching professional friend, Joel Grose. As I shared your insights and we watched the video together we were in complete agreement that MM is incorrect throughout this video. But, Joel provided a rationale for why MM is incorrect, as also highlighted by Homer Kelley and Lynn Blake, and that is that MM is teaching what he FEELS, not what is actually happening or occurring at specific times during his swing.
For example, MM feels like he doesn't rotate his hips or body, so he puts that "feel" into words, but in reality we know and see he is rotating. MM said that Jack FELT like the weight of the club carried him through his downswing and he didn't think once about his hips, but we know in reality that Jack had a very aggressive hip rotation. MM said that he feels acceleration through the impact zone as his left leg straightens and his left hip moves behind him, but as you stated this is due to swing biomechanics that occur from p4 to p5.5, not what is happening through the impact zone. MM does the same with many of his wrongheaded teaching tips.
The problem is compounded when his students apply MM feels to their own swings, based on how it feels to them. Many times the student may have a similar feel as MM, so they have validation, even though it is all based on feel that most often is not correct based on actual biomechanics. Thus, the teacher and student are all wrapped up in the same misinformed mindset.
MM, like most golf instructors, teach what they feel and put those feels into words. This is a major problem, as illustrated in MM instructional videos, because it hides the truth.
UG
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Post by dubiousgolfer on Oct 21, 2019 6:38:17 GMT -5
Dr Mann Ref: MM Gas Pedal Isn't MM using Dr Kwons theory about vertical GRFs to help rotate the pelvis and a secondary rotation of the upper torso and left shoulder socket (depending on the golfers pelvic/torso hula hula separation) to help create the release of PA#4 ? I've looked at this Dr Kwon diagram again and it doesn't make any sense to me . If you look at that diagram on the right , the COM of the body will tend to rotate towards the tail end of that F force . Imho , this will just cause the right side of the pelvis to move 'down and out' if the COM is instantaneously positioned close to the right side of the pelvis. The nearest fulcrum the COM can rotate around is the left hip joint (close to that F force vector). If that F is very large compared to the limited movement of the left hip up and back , I can only assume this could cause more right hip movement 'down and out' compared to the left hip movement 'up and back' which might cause a 'butt tuck' type of movement . It would be interesting to see the comparative movement of the right hip vs left hip in Dr Kwon's research and how they vary with that F force. DG
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Post by syllogist on Oct 21, 2019 6:55:45 GMT -5
Hi Dr. Mann,
Miura stated in his research paper that the "inward pull" would have to occur during the "impact stage" (release) of the swing and that velocity of the pull and not the magnitude of the pull would increase clubhead speed where, during this stage, there would be no other means to increase clubhead speed. Further, the inward pull would have to be opposite the direction of centripetal force. Thus, in his simulator, the direction of force of the activator is vertical from a face-on view.
Around the impact stage, the grip moves downward, levels off, and then rises. So presumably, during this phenomenon, one would have to pull "upward" with meaningful velocity to achieve any gains beyond what "naturally" occurs during this phase. The 6% to 7% speed gain from his simulator was based on force applied perfectly in the opposite direction of centripetal force during the impact stage. I doubt that this can happen in any meaningful way in a real swing.
S
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Post by dubiousgolfer on Oct 21, 2019 7:37:43 GMT -5
Hi S I think the only increase in clubhead speed (especially if there is forward shaft bend happening from P6-P7) is caused by a force across the COM of the club as shown in the diagram below. Imho , the same physics that creates the release of PA#2 is the same for 'Parametric Acceleration' (which seems to be reserved as a definition from P6.5-P7 for some reason). DG
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Post by imperfectgolfer on Oct 21, 2019 9:30:30 GMT -5
Jeff, I had an interesting discussion regarding MM's no rotation video with my teaching professional friend, Joel Grose. As I shared your insights and we watched the video together we were in complete agreement that MM is incorrect throughout this video. But, Joel provided a rationale for why MM is incorrect, as also highlighted by Homer Kelley and Lynn Blake, and that is that MM is teaching what he FEELS, not what is actually happening or occurring at specific times during his swing. For example, MM feels like he doesn't rotate his hips or body, so he puts that "feel" into words, but in reality we know and see he is rotating. MM said that Jack FELT like the weight of the club carried him through his downswing and he didn't think once about his hips, but we know in reality that Jack had a very aggressive hip rotation. MM said that he feels acceleration through the impact zone as his left leg straightens and his left hip moves behind him, but as you stated this is due to swing biomechanics that occur from p4 to p5.5, not what is happening through the impact zone. MM does the same with many of his wrongheaded teaching tips. The problem is compounded when his students apply MM feels to their own swings, based on how it feels to them. Many times the student may have a similar feel as MM, so they have validation, even though it is all based on feel that most often is not correct based on actual biomechanics. Thus, the teacher and student are all wrapped up in the same misinformed mindset. MM, like most golf instructors, teach what they feel and put those feels into words. This is a major problem, as illustrated in MM instructional videos, because it hides the truth. UG I can agree that MM's golf instructional teaching is based on personal "feel" rather than based on a sound knowledge of TGM mechanics and golf biomechanics - and that is a major flaw in his golf instructional teaching approach. Jeff.
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Post by imperfectgolfer on Oct 21, 2019 9:40:05 GMT -5
Dr Mann Ref: MM Gas Pedal Isn't MM using Dr Kwons theory about vertical GRFs to help rotate the pelvis and a secondary rotation of the upper torso and left shoulder socket (depending on the golfers pelvic/torso hula hula separation) to help create the release of PA#4 ? I've looked at this Dr Kwon diagram again and it doesn't make any sense to me . If you look at that diagram on the right , the COM of the body will tend to rotate towards the tail end of that F force . Imho , this will just cause the right side of the pelvis to move 'down and out' if the COM is instantaneously positioned close to the right side of the pelvis. The nearest fulcrum the COM can rotate around is the left hip joint (close to that F force vector). If that F is very large compared to the limited movement of the left hip up and back , I can only assume this could cause more right hip movement 'down and out' compared to the left hip movement 'up and back' which might cause a 'butt tuck' type of movement . It would be interesting to see the comparative movement of the right hip vs left hip in Dr Kwon's research and how they vary with that F force. DG That diagram refers to the vertical GRMs operating in the frontal plane and it causes a tilt of the entire trunk (pelvis and upper torso) in a counterclockwise direction around an imaginary COM of the body (and not around any particular leg/hip joint). It is therefore difficult for me to understand how it will specifically affect motion at the level of each hip joint. Dr. Kwon also referred to horizontal GRMs which primarily cause a counterclockwise rotation of the pelvis.
Jeff.
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Post by imperfectgolfer on Oct 21, 2019 9:43:55 GMT -5
Hi Dr. Mann, Miura stated in his research paper that the "inward pull" would have to occur during the "impact stage" (release) of the swing and that velocity of the pull and not the magnitude of the pull would increase clubhead speed where, during this stage, there would be no other means to increase clubhead speed. Further, the inward pull would have to be opposite the direction of centripetal force. Thus, in his simulator, the direction of force of the activator is vertical from a face-on view. Around the impact stage, the grip moves downward, levels off, and then rises. So presumably, during this phenomenon, one would have to pull "upward" with meaningful velocity to achieve any gains beyond what "naturally" occurs during this phase. The 6% to 7% speed gain from his simulator was based on force applied perfectly in the opposite direction of centripetal force during the impact stage. I doubt that this can happen in any meaningful way in a real swing. S Regarding your bold-highlighted statement, I cannot understand how the inward pull can be opposite the direction of the centripetal force. I tend to think of it acting in the same direction as the CP-force, thereby increasing the magnitude of the normal force in his diagrammatic model. Jeff.
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Post by imperfectgolfer on Oct 21, 2019 9:50:58 GMT -5
Hi S I think the only increase in clubhead speed (especially if there is forward shaft bend happening from P6-P7) is caused by a force across the COM of the club as shown in the diagram below. Imho , the same physics that creates the release of PA#2 is the same for 'Parametric Acceleration' (which seems to be reserved as a definition from P6.5-P7 for some reason). DG I cannot understand your images. You have drawn a red arrow that is directed in the same direction as the longitudinal axis of the left arm (towards the left shoulder socket). Are you implying that the "force" being exerted on the club handle by the left hand as always being directed in that same direction between P6 and impact? I personally think of the "force" being exerted on the club handle by the left hand as always being directed in the direction of the hand arc path - as seen in the following Miura diagram. Jeff.
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Post by syllogist on Oct 21, 2019 10:30:36 GMT -5
"Regarding your bold-highlighted statement, I cannot understand how the inward pull can be opposite the direction of the centripetal force. I tend to think of it acting in the same direction as the CP-force, thereby increasing the magnitude of the normal force in his diagrammatic model. "
Dr. Mann,
There really can't be an additional force in the same direction as centripetal force in the impact stage that would increase clubhead speed. Also, my summarization of Miura's opening remarks stated such.
Although not in the impact stage and without any prior centripetal force, consider an experiment where the golfer with full wristcock holds stationary a club vertical to the ground. The golfer then moves his hands targetward. Such force will act on the clubhead and cause it to accelerate downward. The faster the golfer moves his hands targetward, the greater the acceleration of the clubhead. This is a simple example of Miura's notion of parametric acceleration - a force acting perpendicular to the clubhead - except that Miura modeled such while the clubhead experiences centripetal force.
Miura's concept along with potential gains in speed have been widely misunderstood by the golfing community.
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Post by imperfectgolfer on Oct 21, 2019 11:38:43 GMT -5
"Regarding your bold-highlighted statement, I cannot understand how the inward pull can be opposite the direction of the centripetal force. I tend to think of it acting in the same direction as the CP-force, thereby increasing the magnitude of the normal force in his diagrammatic model. " Dr. Mann, There really can't be an additional force in the same direction as centripetal force in the impact stage that would increase clubhead speed. Also, my summarization of Miura's opening remarks stated such. Although not in the impact stage and without any prior centripetal force, consider an experiment where the golfer with full wristcock holds stationary a club vertical to the ground. The golfer then moves his hands targetward. Such force will act on the clubhead and cause it to accelerate downward. The faster the golfer moves his hands targetward, the greater the acceleration of the clubhead. This is a simple example of Miura's notion of parametric acceleration - a force acting perpendicular to the clubhead - except that Miura modeled such while the clubhead experiences centripetal force. Miura's concept along with potential gains in speed have been widely misunderstood by the golfing community. I have no idea what you are describing. We seem to be operating in different mental universes when it comes to understanding Miura's concept of "parametric acceleration". Jeff.
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Post by dubiousgolfer on Oct 21, 2019 17:16:07 GMT -5
Hi S I think the only increase in clubhead speed (especially if there is forward shaft bend happening from P6-P7) is caused by a force across the COM of the club as shown in the diagram below. Imho , the same physics that creates the release of PA#2 is the same for 'Parametric Acceleration' (which seems to be reserved as a definition from P6.5-P7 for some reason). DG I cannot understand your images. You have drawn a red arrow that is directed in the same direction as the longitudinal axis of the left arm (towards the left shoulder socket). Are you implying that the "force" being exerted on the club handle by the left hand as always being directed in that same direction between P6 and impact? I personally think of the "force" being exerted on the club handle by the left hand as always being directed in the direction of the hand arc path - as seen in the following Miura diagram. Jeff. Dr Mann That Miura diagram above doesn't make any sense to me . It looks like the tangential force he is showing is in line with the clubshaft but I cannot see how that force will increase the 'angular velocity' of the club. Does it make any sense to you how a force applied by the hands (on the club handle) along the hand path will increase the angular velocity of the club? It might increase the linear speed of the clubhead as the 'handle/whole club' gets pulled in a targetwards direction from P6-P7 but that's going to be small compared to its peak clubhead speed (caused by an increase in its angular velocity). Actually Mandarin (I know you may have doubts regarding his opinions) has produced some graphs showing all the forces and torques created at 2nd pivot of a double pendulum (which can represent the wrists in a golfer). If you look at graph 31b below you can see that radial force along the lead arm is responsible for producing a wrist torque from P5.5-P7. This is not a muscular wrist torque but is caused by an increased 'pull force tension' in the lead arm across handle of club (like my Sadlowski diagram above) that causes a 'Moment of Force' on the COM of the club (which in turn causes a torque on the wrists) that increases the clubs angular velocity. Forces in line with the clubshaft, gravity, and forces along the hand path seem to produce negligible torque at the 'wrists' (see graphs below , although there is a positive bracing torque caused at wrist level from P4-P5). Unfortunately , the maths and physics to explain the double-pendulum (or a driven double-pendulum) is very complicated and I have no way of checking the accuracy of the maths (way beyond my capabilities). DG PS. Hand speed (and Clubhead speed ) along its 'less curvilinear path' (from P4-P5.5 -ie. Release) is still important to maximise because 'clubhead speed' just gets added to when 'Release' occurs. Double pendulumExternal forces applied: torques τ1, τ2, respectively at center joint and hinge joint and gravity forces M1 g, M2 g. Torque τ1 is constant and the torque τ2 at the hinge is modeled to form a 90 degrees dead stop, preventing back knifing. Scrutiny of the governing differential equations (2) and (3) of the double pendulum show clearly that there is, even for such a simple two body system, already a complex non linear interaction taking place between the two segments, resulting in various inertial forces and torques. To more conveniently grasp the relative importance of the forces / torques acting on the 'wrist' joints, I have derived their magnitude / direction and presented these force vectors and associated torques in graphical form. Figs 28a...33a show the six forces acting at the wrist joints. Four inertial forces due to angular and radial acceleration of the two segments in addition due to gravity and wrist torque. Whereas Figs 28b...33b show the corresponding torques resulting form these various forces acting at the wrist joints. The Newton-Euler equation for the rotation of the outer segment, considered as a free body, is given by : "RELEASE_MYTH_REAL_1_38.gif" ∑ (external torques + inertial torques) The 'b' graphs express this equation graphically : M2 "RELEASE_MYTH_REAL_1_39.gif" q2''[t] is given by the first graph, Fig 28b, and the 5 remaining ones, Figs 29b to 33b, are the various torques acting on the hinge joint. Hence the first is the sum of the five remaining. The forces and torques are shown using the same scale to allow comparison. Notice that the joint force associated with the radial (centripetal) acceleration of the club, see Fig29a, is much larger than the other joint forces, and yet producing zero torque contributing to the release action. This large force is usually and erroneously being taken as the centrifugal force acting outward on the clubhead. The beauty of the graphical presentation of forces and torques is that it gives a clear instantaneous picture of the relative importance of the various joint forces during all of the down swing. It can be seen immediately that the release torque is generated almost exclusively by the radial (centripetal) acceleration of the arm, Figs 31a/b. Some interesting conclusions can be drawn immediately. 1) release torque is generated primarily by the radial acceleration of the arms. 2) therefore, path of hands is important as radial acceleration is due to a curvilinear path, a circle in our analysis. 3) furthermore, speed of hands is important as radial acceleration is proportional to hand speed squared. The surprising fact for many will be probably that the very large centripetal acceleration of the club has no bearing on release. Usually and erroneously one takes this large force to be a centrifugal force acting out from the clubhead. Even admitting, for a brief moment, this to be true it still could not contribute to release as it is a vector aligned with the club shaft during release, and hence can't produce any release torque.
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