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Post by imperfectgolfer on Jun 5, 2021 10:30:17 GMT -5
Here is my analysis of Shawn Clement's golf swing action. Here are capture images of his backswing/downswing action.
Image 1 is at address.
Image 2 is his mid-backswing position (P2.5). Note that he is swinging his arms upwards while he rotates his pelvis/upper torso at the same rotational speed. Note that he is upcocking his lead wrist to get lag but he is not pronating his lead forearm because he has a near-vertical left arm/clubshaft motion that will get his club to lie just behind his head (and over his neck) at P4 (image 3). Note that his right forearm is very supinated at P2.5 and his right elbow ends up below his hands at P4 after he folds his right elbow.
Image 4 is at P5.5. Note that he dropped his hands down to waist level very fast before he has rotated his pelvis to square. If he squared his pelvis by P5 then his right shoulder would have moved far too much outwards (toward the ball-target line) and he would come OTT, and he would be unable to "slot" his club (as seen in image 4) that will allow for an in-to-out clubhead path. Note that when he "slots" his club that there is no rotation of his lead arm/hand - the lead arm simply drops down into the "slot".
Image 4 is at impact. Note that he is nearly square to the ball-target line at impact. Note that he does not have an open pelvis at impact - despite using a very strong lead hand grip. Note that he does not use an on-top delivery action where his trail palm faces the ground at P5.5 - despite the fact that his club comes down a very steep path.
I now believe that adopting a very strong lead hand grip and very strong trail hand grip is highly recommended for golfers who cannot generate torso-pelvic separation.
Jeff.
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Post by dubiousgolfer on Jun 5, 2021 10:58:48 GMT -5
Dr Mann
So how is SC releasing PA#4?
DG
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Post by imperfectgolfer on Jun 5, 2021 12:06:01 GMT -5
Dr Mann So how is SC releasing PA#4? DG SC would claim that his arms drop due to gravity, but gravity is too weak a force. I think that the small degree of movement of his left shoulder socket between P4 => P5.5 causes the release of PA#4 simultaneously combined with the use of his left-and-right shoulder girdle muscles (especially his lats). Jeff.
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Post by dubiousgolfer on Jun 6, 2021 9:19:43 GMT -5
SC is certainly generating a lot of clubhead speed if this video is representative of his driving distance (ie . see 9:32 where the system is showing a driving distance of 307 yds). Even though he is 55 he must be quite strong in the lat area. With his zero hula-hula he seems very flexible in his hip joints to get such a pelvic rotation in the follow-through without spinning his front foot .
DG
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Post by imperfectgolfer on Jun 6, 2021 13:46:24 GMT -5
DG,
SC has a very fluid pelvic and upper torso rotary motion. It is amazing that he can generate clubhead speeds of 120mph with his driver as an end-result of such an effortless swing action.
His daughter, Sav, has a superb pelvic motion during her downswing.
Jeff.
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Post by dubiousgolfer on Jun 9, 2021 9:05:30 GMT -5
I was listening to this video again and noticed the MA reply to Nick Clearwaters question (11:39) about a 'post' measurement at impact.
MA says "they are going to be on the left side" but that is not what Dr Kevin Ball found in his research for reverse foot golfers (see below).
"The main and most important conclusion of this study is two different styles exist in the weight transfer profile in the golf swing. In this study, two major groups were identified by cluster analysis; named as the Front Foot group and the Reverse group. The Front Foot group began the swing from a balanced position, moved the weight towards the back foot in backswing, rapidly forward in early downswing and continued towards the front foot through ball contact. The Reverse group was similar to the Front Foot group in backswing and early downswing swing events. However from early downswing the forward movement of weight stopped and began to move towards the back foot through ball contact. Both groups included professional or elite amateur golfers and no difference existed in Club Velocity at ball contact or Handicap indicating neither technique was a technical error."
I can only assume that the majority (if not all) the golfers that were tested by MA were front foot golfers. Further Dr Sasho MacKenzie says in the below video (from 4:24-5:25) that even though Ball/Best found a correlation between 'peak COP velocity' towards the target and clubhead speed, it did not apply to reverse foot style players like big hitters such as Justin Thomas.
I am assuming that SMK 'indicator for clubhead speed' where golfers must try and maximise vertical ground forces 'as much as possible' at clubshaft vertical in downswing applies to both front and reverse foot golfers.
DG
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Post by imperfectgolfer on Jun 9, 2021 13:26:58 GMT -5
I agree with MA that all pro golfers move their pelvis toward their lead foot between P4 => P7 - irrespective of whether they are rear-post, center-post or front-post golfers at P4. Front-post golfers already have their pelvis forward at P4, but a rear-post golfer has to have a left-lateral pelvic shift movement happening between P4 => P7 in order to get the pelvis more forward (targetward) by impact. Having the pelvis forward at impact does not necessarily correlate with COP measurements at impact, because some pro golfers will have a reverse-foot pattern of COP measurement at impact while other pro golfers will have a front-foot pattern of COP measurement at impact. MA does not care about the actual value of the COP measurement at impact and he is mainly concerned with the Swing Catalyst's horizontal torque, rotary torque and vertical force measurements happening in the early-mid downswing. A rear-post golfer, who uses a "glider" pattern will likely have a high horizontal torque value happening very early in the downswing between P4 => P4.5. A center-post golfer, who uses a "spinner" pattern, will likely have a high rotary torque value peaking at P5. A front-post golfer, who uses a "launcher" pattern, will likely have a high vertical force value peaking between P5.5 => P6. The actual COP measurements at impact are not relevant to MA's classification system. Here is Sasho's graph showing the results of his study of pro golfers, which showed a very high correlation between clubhead speed and a high COP measurement under the lead foot at shaft vertical. Note that he found a high correlation R value of 0.91. Scott Lynn repeated the study on pro golfers and found a very low correlation coefficient value of 0.33 at shaft vertical - see graph below. I trust Scott Lynn's results, and not Sasho's results. If you view Scott Lynn's presentation in session number 5, you can learn a lot. Jeff.
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Post by utahgolfer on Jun 9, 2021 15:07:45 GMT -5
Jeff, Scott’s last name is actually Lynn and yes his presentation is terrific. I have to speak up for those with two first names. His discovery and naming of the kinetic sequence is huge, and the premise that it might be the most consistent trait of all good golfers is potentially one of the greatest discoveries on proper golf swing biomechanics. Essentially, it is that from p4 to p6 all three ground reaction forces should peak, with horizontal forces peaking first, rotational forces peaking second, and vertical forces peaking third.
Cream always rises to the top and Scott Lynn appears to be top-rate cream in the world of biomechanics.
Jim
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Post by imperfectgolfer on Jun 9, 2021 17:51:56 GMT -5
Jeff, Scott’s last name is actually Lynn and yes his presentation is terrific. I have to speak up for those with two first names. His discovery and naming of the kinetic sequence is huge, and the premise that it might be the most consistent trait of all good golfers is potentially one of the greatest discoveries on proper golf swing biomechanics. Essentially, it is that from p4 to p6 all three ground reaction forces should peak, with horizontal forces peaking first, rotational forces peaking second, and vertical forces peaking third. Cream always rises to the top and Scott Lynn appears to be top-rate cream in the world of biomechanics. Jim I corrected Scott Lynn's name. I actually think that the kinetic sequence with respect to ground reaction forces are self-evident. Think of how I described the forces being exerted under the feet when I described a pelvic motion being induced due to a contraction of the right-sided lateral pelvic rotator muscles. I stated that a golfer should increase his pressure-loading of his right foot at P4 so that when he contracted his right-sided lateral pelvic rotator muscles between P4 => P5, a force would be produced under his right foot that would be directed away from the target and back away from the ball-target line. That force would induce the pelvis to rotate counterclockwise and also cause a shift of the pelvis to the left if the pelvis was significantly rightwards-loaded at P4. Then, I stated that a golfer should be pushing down into the ground under his left foot between P5 => P5.5 by starting to contract his left thigh's vastus lateralis muscle and that would produce the vertical force described by Scott Lynn. I still favor my way of thinking because I do not like the way he describes how to generate the pelvic rotary torque phenomenon using horizontal GRM's. He talks about pushing the right forefoot away the ball-target line in order to get the right pelvis to rotate counterclockwise while simultaneously pushing the left forefoot towards from the ball-target line in order to get the left pelvis to rotate counterclockwise. I think that the dual horizontal GRM-generation phenomenon will induce right hip spinning where the right buttocks prematurely leaves the tush line. That doesn't happen in many pro golfers. Here is Jamie Sadlowski's pelvic motion. Note that he keeps his right buttock against the tush line while pulling his left buttock back towards the tush line during the hip-squaring phase between P4 (image 1) => P4.5 (image 2). Here is an image from the TR/MA video sessions. The golfer is holding a bar against his right thigh where there is a rubberised rope attached to the right-sided end of the bar. Mike Adams is instructing the golfer to push the right-side end of the bar against his gloved hand, and that induces the right hip joint to move counterclockwise away from the tush line. That technique is recommended for rear-dominant golfers who seemingly use their rear leg to induce a pelvic rotation, but that would cause the right buttock to prematurely leave the tush line. I wonder which pro golfers use that technique- because it cannot be happening in pro golfers who keep their trail buttock against the tush line while rotating their lead buttock back towards the tush line. It may apply to "front-post" pro golfers who are "launchers" and who use the straightening trail leg to induce their "launch" action.
Jeff.
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Post by dubiousgolfer on Jun 9, 2021 21:13:27 GMT -5
Jeff, Scott’s last name is actually Lynn and yes his presentation is terrific. I have to speak up for those with two first names. His discovery and naming of the kinetic sequence is huge, and the premise that it might be the most consistent trait of all good golfers is potentially one of the greatest discoveries on proper golf swing biomechanics. Essentially, it is that from p4 to p6 all three ground reaction forces should peak, with horizontal forces peaking first, rotational forces peaking second, and vertical forces peaking third. Cream always rises to the top and Scott Lynn appears to be top-rate cream in the world of biomechanics. Jim I actually spent over an hour looking at this you-tube video below which went into a lot of detail describing the ground reaction forces for several pros (including some long drivers) and also provided a demonstration of how he would improve a few sample golfers 'torque' grfs (but it did seem like he was ingraining a right hip spinning action with those elastic resistance bands) Dr Mann's biomechanical explanation about how to perform an optimal pelvis rotation is far more detailed and makes logical sense. DG
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Post by utahgolfer on Jun 9, 2021 22:37:07 GMT -5
Thanks DG, I'll take a look at the video. Thanks Jeff for your input.
To me, all of this blends together. The truth is somewhere in it all, but it depends on the individual player and what works on the practice tee and course. SL has a model that shows the GRFs increase and decrease at specific times. At p4, if the right foot is pushing toward the ball target line and target-ward, and the left foot is pushing away from the target line simultaneously, then this describes what is happening. To say it causes a hip spin is another story. What the data suggest is that good golfers generate GRFs from p4 to p6 in a specific and ordered pattern. It needs to happen and when it happens correctly it increases club head and ball speed. Pretty simple. And, it might be the most consistent swing pattern that all good players do.
It is liberating to focus on the outcome and not on how the swing looks or feels. If I change my GRFs and increase my driver distance by 25 yards, then what else matters. I don't care if my pelvis comes off the tush line if my outcomes are what I want. I don't care if both feet come off the ground if my ball carry is 280 yards.
This is the beauty of the ultimate golf lesson as organized by MA and TR. It is outcome-based without regard for any previous instructional dogma. All that matters is ball speed, accuracy, and scoring. I like their approach.
Jim
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Post by imperfectgolfer on Jun 9, 2021 22:52:55 GMT -5
Thanks DG, I'll take a look at the video. Thanks Jeff for your input.
To me, all of this blends together. The truth is somewhere in it all, but it depends on the individual player and what works on the practice tee and course. SL has a model that shows the GRFs increase and decrease at specific times. At p4, if the right foot is pushing toward the ball target line and target-ward, and the left foot is pushing away from the target line simultaneously, then this describes what is happening. To say it causes a hip spin is another story. What the data suggest is that good golfers generate GRFs from p4 to p6 in a specific and ordered pattern. It needs to happen and when it happens correctly it increases club head and ball speed. Pretty simple. And, it might be the most consistent swing pattern that all good players do.
It is liberating to focus on the outcome and not on how the swing looks or feels. If I change my GRFs and increase my driver distance by 25 yards, then what else matters. I don't care if my pelvis comes off the tush line if my outcomes are what I want. I don't care if both feet come off the ground if my ball carry is 280 yards.
This is the beauty of the ultimate golf lesson as organized by MA and TR. It is outcome-based without regard for any previous instructional dogma. All that matters is ball speed, accuracy, and scoring. I like their approach. Jim
My biomechanical approach to creating pelvic motion in the downswing - using the right-sided lateral pelvic rotator muscles - is more limited in value because it is not suitable for front-post golfers. I actually do like the MA/SL approach based on "real life" measurements of horizontal, rotary and vertical torques. However, although there is a standard kinetic sequence in terms of the sequencing of those 3 forces, the timing and magnitude of each of those 3 forces varies widely in pro golfers. MA/SL showed that some pro golfers have no need for any horizontal force because they mainly depend on their vertical force while other pro golfers have very small vertical forces and they mainly depend on their rotary torque (eg. Gary Woodland). There is also more "art" than "science" when it comes to drills designed to alter the timing and magnitude of those 3 forces. However, I readily concede that their "GRF measurement-based" approach is much more sophisticated than my more simplistic biomechanical approach. Jeff.
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Post by utahgolfer on Jun 10, 2021 7:55:05 GMT -5
It's all about learning and progressing. Everything is a team effort. DG introduced this topic. Jeff and DG dissect every word and principle. We all benefit from trying to come to an understanding of the truth. Our world changes when this happens. I watched this video this morning and I see things differently now. Horizontal, rotational, vertical. Good swings generate these downswing forces early and in order. This 10-year-old makes it look easy!
Jim
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Post by dubiousgolfer on Jun 10, 2021 8:39:23 GMT -5
If 'MA/TR/Dr Lynn/Dr MacKenzie/Dr Cheetham' think that grfs can be used as an 'indicator' to improve the biomechanics of golfers with differing patterns of 'body joint degrees of freedom' and musculature stature, then I can appreciate that opinion. But do they know what the optimal biomechanics of 'golfer body types' are because there isn't enough data to monitor the forces being applied by the hands or how each muscle is firing to provide overwhelming proof.
But I agree that if it works well and there is enough evidence to prove it works , then its another possible way to teach the golf swing.
Personally , I think that grfs are used as constraining forces to :
a. Prevent the body from obstructing its own intended movements b. Restricting body joints in space to facilitate the stretch shorten cycles.
For example (point a) , if you torque your upper torso by contracting your external/internal obliques in the downswing, there will be an equal and opposite torque applied to the pelvis. This is similar to you sitting in a swivel chair , feet not touching the ground , then attempting to rotate your upper torso CCW will cause your pelvis to rotate in the CW direction. Obviously , that is not an optimal type of movement in the golf swing , which is why we need grfs to prevent our body parts getting in the way of our intended swing.
Look at this question raised to SMK on twitter
Question: "Riddle me this:
Large ground reaction forces create high club head speed
OR
High club head speed creates large ground reaction forces
Which is the cause, and which is the effect?" ---------------------
SMK Answer: Consider that when clubhead speed is the highest (impact) GRF is very low. When GRF is very large and increasing (shaft vertical downswing) the golfer is actually in a position where their application of force to the grip (to increase clubhead speed) will be reducing GRF.
--------------------
So it seems that GRF is more an effect of what forces/torques are being applied to the club and for me, personally , I'd rather like to know the detailed biomechanics on what major muscles are being used (by each body type) to create those forces.
DG
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Post by imperfectgolfer on Jun 10, 2021 9:18:13 GMT -5
DG, I think that a GRF can be produced in order to act as a constraining factor. For example, Scott Lynn has measured markedly negative horizontal GRFs in the mid-late downswing as the vertical GRF under the lead foot maximises, and that negative horizontal GRF acts as a "braking" mechanism that prevents the pelvis shifting excessively targetwards in the later downswing and through impact. He postulates that the lead gluteus medius muscle is used to create that negative horizontal GRF. However, in an active downswing pelvic motion in a rear-post golfer, where the pelvis shifts targetwards between P4 => P5, surely the horizontal GRF generated by the rear foot must be positive in order to move the pelvis targetwards. Also, try a simple experiment. Perform your usual golf swing action, but then increase the vertical GRF under your lead foot at ~P5.5 in order to elevate the left shoulder socket more actively. Surely, the increased magnitude of the vertical GRF is used to induce a positive biomechanical motion and it is not used as a constraining force.
Another example - when one contracts the right-sided lateral pelvic rotator muscles between P4 => P5, it produces a horizontal GRF under the right foot that is directed away from the target and away from the ball-target line. That horizontal GRF is used to induce a counterclockwise pelvic rotation and it is not used as a constraining force. Jeff.
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