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Post by dubiousgolfer on Apr 20, 2023 12:33:16 GMT -5
Dr Mann
So at what position in the downswing is RF releasing PA#2 compared to Rory? If you look at the time spacing between the point of release and impact, it seems that RF has released PA#2 earlier.
DG
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Post by imperfectgolfer on Apr 20, 2023 12:43:41 GMT -5
Dr Mann So at what position in the downswing is RF releasing PA#2 compared to Rory? If you look at the time spacing between the point of release and impact, it seems that RF has released PA#2 earlier. DG I agree that Rickie is releasing PA#2 earlier in the mid-downswing, but he still has ~100 degrees of lead wrist angle at the same time point that Rory starts his PA#2 release, because Rory has already given up ~10 degrees of his lead wrist angle as a result of casting before he starts to release PA#2. Jeff.
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Post by dubiousgolfer on Apr 20, 2023 18:19:26 GMT -5
Dr Mann I've listened to some of that SMK podcast and the interesting part was around -1:06:25 to -1:01:00 regarding a study by Chu on 308 amateur golfers. Apparently the wrist hinge angle (ie. angle between lead arm and shaft) at 40 msecs before impact (P6) showed the best association with clubhead speed than any other variable they measured at all the different points in the golf swings. The average wrist hinge angle was 145 degrees at p6 which gave a 140 mph ball speed and for every 10 degrees less angle between shaft and arm (ie. more lag), the ball speed would increase by 5mph. At -26:26 to -22:40 SMK says in the Chu study there was a wide range of wrist angles at P6 and ball speeds, but if you did that study on PGA pros (SMK has a database of 130) , you don't see much correlation. Just listening now to the question at -24:11 to -13:00 regarding how hand speed contributes to clubhead speed. Apparently hand speed should peak halfway between shaft vertical and shaft parallel on the downswing about 60 degrees from parallel. But increasing the peak hand speed might not necessarily have a correlation with clubhead speed (some paradox regarding Newtons 3rd Law of motion). Also there is no correlation between hand speed at impact and clubhead speed. DG I've listened to that podcast again: Apparently there is a 0.7 correlation between peak hand speed and clubhead speed for Tour Pros but it is not necessarily a cause and effect. Therefore, if you advise a golfer to try and increase their peak hand speed early in the golf swing , there is no guarantee it will increase clubhead speed. SMK gave an example that one could pull faster on the club than tour pros but end up with too much lag and not be able to fully release the club before impact. DG
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Post by dubiousgolfer on Apr 21, 2023 9:09:26 GMT -5
Dr Mann So at what position in the downswing is RF releasing PA#2 compared to Rory? If you look at the time spacing between the point of release and impact, it seems that RF has released PA#2 earlier. DG I agree that Rickie is releasing PA#2 earlier in the mid-downswing, but he still has ~100 degrees of lead wrist angle at the same time point that Rory starts his PA#2 release, because Rory has already given up ~10 degrees of his lead wrist angle as a result of casting before he starts to release PA#2. Jeff. Dr Mann Here is the grip speed of Rory at various P positions: Rory McIlroy (max grip speed at ~P5.5 of 25mph) Position Clubhead speed (mph) Grip Speed (mph) P6.5 116 21.5 P7 121 20.3 Here is the grip speed of Rickie Fowler for those similar positions using Gears 3D video below: Max Grip Speed 22.56 mph at ~P5.5 Position Clubhead speed (mph) Grip Speed (mph) P6.5 108.83 18.10 P7.0 113.10 15.07 Rory and RF have similar PA2 angles at the position point of Rory's PA#2 release, but Rory's grip/hand speed is obviously superior. I don't have the tools to identify their hand paths from P5.5-P7 but if they are similar , then that might explain the greater clubhead speed for Rory. If the hand paths are similar but Rory 'turning the corner' at a quicker speed, then won't that create greater angular acceleration of the club from P5.5-P7? DG
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Post by imperfectgolfer on Apr 21, 2023 10:08:15 GMT -5
I agree that Rickie is releasing PA#2 earlier in the mid-downswing, but he still has ~100 degrees of lead wrist angle at the same time point that Rory starts his PA#2 release, because Rory has already given up ~10 degrees of his lead wrist angle as a result of casting before he starts to release PA#2. Jeff. Dr Mann Here is the grip speed of Rory at various P positions: Rory McIlroy (max grip speed at ~P5.5 of 25mph) Position Clubhead speed (mph) Grip Speed (mph) P6.5 116 21.5 P7 121 20.3 Here is the grip speed of Rickie Fowler for those similar positions using Gears 3D video below: Max Grip Speed 22.56 mph at ~P5.5 Position Clubhead speed (mph) Grip Speed (mph) P6.5 108.83 18.10 P7.0 113.10 15.07 Rory and RF have similar PA2 angles at the position point of Rory's PA#2 release, but Rory's grip/hand speed is obviously superior. I don't have the tools to identify their hand paths from P5.5-P7 but if they are similar , then that might explain the greater clubhead speed for Rory. If the hand paths are similar but Rory 'turning the corner' at a quicker speed, then won't that create greater angular acceleration of the club from P5.5-P7? DG Your posted measurements comparing Rory and Rickie show how complex it is to decide which factors are causally responsible for a pro golfer's swing power. I have argued, using empirical reasoning, that to get the maximum clubhead speed at impact with a driver, that one needs to maximise the speed of release of PA#4 in order to get the maximum lead hand speed at ~P5.5. It is interesting that there is only a~2.4 mph difference in their hand speed at P5.5, which suggests that they release PA#4 with equal efficiency. It would seem that Rory releases PA#2 slightly more efficiently than Rickie allowing him to get a 8mph difference in clubhead speed at impact. Whether that gain is due to the small difference in hand speed as they "turn the corner" between P5.5 => P6.2, or whether it is due to how efficiently they generate a large centripetal MoF due to lead shoulder elevation, or whether it is due to other unknown factors is not knowable due to the lack of scientific research data. I still cannot really understand why certain pro golfers can release PA#2 more efficiently than their peers, and I do not understand whether slowing down the hand speed between P5.5 => P7 to a comparatively larger degree is advantageous or disadvantageous. For example, Dustin Johnson can apparently maintain a very high hand speed between P5.5 => P7 (compared to the "average" pro golfer).
The following clubshaft angular acceleration differences between Rory McIlroy and JB Holmes and Jordan Spieth and Zach Johnson still stupefies me.
L column is ~P4 => P5, M column is P5 => P6 and N column is P6 => impact.
Zach accelerates his clubshaft the fastest between P4 => P5, but he then slows down in the mid-late downswing.
The most amazing measurement is JB Holmes 247 measurement between P6 => P7! Note how he can maintain a much faster clubshaft acceleration profile compared to Rory McIlroy with little slowing down compared to the peak values which happen between P5 => P6 (in all those golfers). I don't know what he is doing to make it possible.
I would very much like to see Phil Cheetham publish the hand speed profiles and clubshaft acceleration profiles of the >100 pro golfers in his data base for the P4 => P5.5 and the P5.5 => P7 time periods - so that we can see if there is any "direct correlation" pattern. I suspect that DHers are more likely to have higher lead hand speeds between P6 => P7 and also between P7 => P7.2 - compared to non-DHers. However, I would love to examine the "real life" data to determine whether my suspicions are correct/incorrect.
Jeff.
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Post by imperfectgolfer on Apr 21, 2023 10:31:56 GMT -5
Dr Mann The angle between the yellow lines on Milo's image is basically the PA3 angle post impact. If Milo was retaining an intact GFLW/LFFW in his downswing and through impact , wouldn't there still be an angle in the 'wedge' between lead forearm and shaft? There would have to be unless the lead forearm and club shaft were swinging instantaneously on the same plane and a line drawn from the forearm extended through the shaft. Are you saying in image 2 for Domenic Mazza, image 4 for Fitzpatrick, image 4 for Berger , that their lead arm and club shaft are perfectly in line? That a longitudinal axis through their lead forearm would pass through the longitudinal axis of the shaft? If yes , then the lead wrist angle would be 180 degrees, but if not, then the angle would be less than 180 degrees. DG DG - I missed seeing this post before, so I am sorry for my delayed reply. Milo Lines uses a very strong lead hand grip so he does not use the intact LFFW/GFLW swing technique. His lead wrist angle (clubhead lag angle) is always near-parallel to the swingplane, so it must be measured in that plane. The accumulator #3 angle at impact is measured at right angles to the swingplane, and it has no connection with his "lead wrist angle" and it is reflective of how much he extends his lead arm outwards in the direction of the ball-target line and how much he extends (or flexes) his lead wrist in the plane of lead wrist hinging. I am asserting that Milo Lines, Domenic Mazza, Matthew Fitzpatrick and Daniel Berger all get a lead wrist angle of 180 degrees post-impact due to a greater degree of ulnar deviation of their lead wrist that happens soon after impact, and that causes the clubshaft to be temporarily straight-line-aligned with their lead forearm (as viewed relative to the swingplane). Jeff.
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Post by dubiousgolfer on Apr 21, 2023 11:59:23 GMT -5
Dr Mann Have you read this article? golf.com/instruction/sasho-speed-test-golf-swing/The article says: ------------------------- This was something Sasho dived pretty deep on in his research, and he found that golfers who tend to rotate and release the club more with their hands transfer more speed to their driver than golfers who use their body to drive their hands through impact with higher speed. Or, put more simply: The more you release the hands, the more speed you’ll probably have with your driver. “They’re really putting the brakes on your hands to get speed out to the club…that scales to the driver” he says. “The only caveat is that maybe this negatively influences your accuracy. ------------------------------- So if I have interpreted this correctly ,if golfers whose 7 iron swing biomechanics involves stalling their grip speed (I don't know from which P position) replicate that same technique in their driver swings , they can achieve a greater scaling up of driver clubhead speed than those golfers who try and retain their grip speed using their body pivot. SMK goes into a little more detail on his twitter account: He has also created a full video but I'm afraid there is a charge for viewing it. vimeo.com/ondemand/7ironvsdriverDG
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Post by dubiousgolfer on Apr 21, 2023 19:36:35 GMT -5
Dr Mann
You said about JB Holmes: "The most amazing measurement is JB Holmes 247 measurement between P6 => P7! Note how he can maintain a much faster clubshaft acceleration profile compared to Rory McIlroy with little slowing down compared to the peak values which happen between P5 => P6 (in all those golfers). I don't know what he is doing to make it possible."
Here is a video below where at 8:22, JB states that he jumps up off the ground.
Doesn't that imply that he may be creating a greater centripetal MOF force to retain the angular acceleration of the club from P6-P7?
DG
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Post by imperfectgolfer on Apr 21, 2023 22:13:41 GMT -5
Dr Mann You said about JB Holmes: "The most amazing measurement is JB Holmes 247 measurement between P6 => P7! Note how he can maintain a much faster clubshaft acceleration profile compared to Rory McIlroy with little slowing down compared to the peak values which happen between P5 => P6 (in all those golfers). I don't know what he is doing to make it possible." Here is a video below where at 8:22, JB states that he jumps up off the ground. Doesn't that imply that he may be creating a greater centripetal MOF force to retain the angular acceleration of the club from P6-P7? DG That's a possible explanation. What we really need is to examine the i) clubshaft acceleration profile, ii) the lead hand speed profile and the iii) the degree of parametric acceleration secondary to lead shoulder elevation (which can increase the centripetal MoF) that happens between P5.5 => P7 in about 100+ pro golfers to determine if there is any likely correlation between these elements. Jeff.
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