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Post by dubiousgolfer on Jan 14, 2020 9:34:23 GMT -5
Dr Mann
In your opinion , is this a good 'Drive-Hold' practice drill?
DG
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Post by imperfectgolfer on Jan 14, 2020 10:54:48 GMT -5
Dr Mann In your opinion , is this a good 'Drive-Hold' practice drill? DG I have no objection to the drill with the cane (which is a very old drill that has been taught for a long time). It is relatively sensitive to clubshaft flipping due to left wrist flipping (left wrist extension), but it is less sensitive to clubshaft flipping due to left forearm supination because if the accumulator #3 angle is small between P7 and P7.4 then it is possible to avoid having the cane hit the left side of the torso during the followthrough despite having a too high clubface ROC through impact due to excessive left forearm supination. Jeff. p.s. I get the impression that Russell has studied my work on the DH-hand release action. He is amazingly productive in terms of generating new golf instructional videos and his 55,000 subscribers must be having a hard time keeping up.
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Post by dubiousgolfer on Jan 14, 2020 18:27:42 GMT -5
Many thanks Dr Mann
I got that impression too that Russell has studied your work and I'm going to put a comment on you-tube asking him that question. Although I don't think he read your article about 'how to optimally rotate the pelvis in the downswing' after seeing this original video below
But then he started to use some information from your article and published a revised video below (not very detailed but definitely 'poached' from your website).
DG
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Post by imperfectgolfer on Jan 14, 2020 19:47:02 GMT -5
DG,
It could well be that Russell uses "stuff" from my golf website, and you used the word "poaching" to describe that phenomenon. I think that the word "poaching" has a negative connotation and I prefer to think that he has simply used some of my "ideas" that he thinks are biomechanically rational. I wish that many more golf instructors would use many of my "ideas" regarding optimum golf swing biomechanics because that will help many more golfers learn how to perform the golf swing better.
By the way, Russell can certainly perform the "correct" biomechanical motions very well when he demonstrates the golf swing action and I wish that I could perform the golf swing as well as him.
Jeff.
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Post by dubiousgolfer on Jan 14, 2020 21:21:37 GMT -5
DG, It could well be that Russell uses "stuff" from my golf website, and you used the word "poaching" to describe that phenomenon. I think that the word "poaching" has a negative connotation and I prefer to think that he has simply used some of my "ideas" that he thinks are biomechanically rational. I wish that many more golf instructors would use many of my "ideas" regarding optimum golf swing biomechanics because that will help many more golfers learn how to perform the golf swing better. By the way, Russell can certainly perform the "correct" biomechanical motions very well when he demonstrates the golf swing action and I wish that I could perform the golf swing as well as him. Jeff. Yes 'poached' is too strong a word. He should have at least mentioned that some of his instruction is based on your articles. DG
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Post by dubiousgolfer on Jan 16, 2020 11:14:04 GMT -5
Dr Mann
Isn't it optimal to achieve a stable clubface (ie. minimal ROC so that the clubface is square to clubhead path) with an intact LAFW (not just intact LFFW) after release of PA#2 but before impact?
I can't imagine that a golfer will be able to time a stable clubface at/during impact (for 4/1000 sec) so that he can then maintain a DRIVE-HOLD condition to P7.2.
How can a golfer 'predict' what the angular velocity of the club will be after impact so that it will match the angular velocity of his whole lead arm? He would have to be able to predict/judge in advance the loss in clubhead angular velocity after impact such that it matched the angular velocity of his lead arm while keeping an intact LAFW.
The below is something that Dave Tutelman emailed to me after I raised questions about club/ball impact and I've underlined a section that interested me.
"There is a lot of violent physics going on in the vicinity of impact. You are looking at forces in the vicinity of 2000 pounds (yes, a TON) and accelerations in the vicinity of 500,000mph/sec (I didn't believe that number either, and checked my math; it checked). Those are not numbers that anatomy can generally deal with, nor are times of less than a millisecond. The golf biomechanics world understands these quantities in terms of physics. The anatomy gets things moving, but in the milliseconds before and after impact, there's nothing anatomy can do to help, if it isn't already doing them."
Doesn't this suggest that the golfer must already be deploying an intact 'LAFW' before impact to achieve Drive-Hold condition during/after impact (up to P7.2)?
DG
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Post by imperfectgolfer on Jan 16, 2020 12:27:28 GMT -5
Dr Mann Isn't it optimal to achieve a stable clubface (ie. minimal ROC so that the clubface is square to clubhead path) with an intact LAFW (not just intact LFFW) after release of PA#2 but before impact? I can't imagine that a golfer will be able to time a stable clubface at/during impact (for 4/1000 sec) so that he can then maintain a DRIVE-HOLD condition to P7.2. How can a golfer 'predict' what the angular velocity of the club will be after impact so that it will match the angular velocity of his whole lead arm? He would have to be able to predict/judge in advance the loss in clubhead angular velocity after impact such that it matched the angular velocity of his lead arm while keeping an intact LAFW. The below is something that Dave Tutelman emailed to me after I raised questions about club/ball impact and I've underlined a section that interested me. "There is a lot of violent physics going on in the vicinity of impact. You are looking at forces in the vicinity of 2000 pounds (yes, a TON) and accelerations in the vicinity of 500,000mph/sec (I didn't believe that number either, and checked my math; it checked). Those are not numbers that anatomy can generally deal with, nor are times of less than a millisecond. The golf biomechanics world understands these quantities in terms of physics. The anatomy gets things moving, but in the milliseconds before and after impact, there's nothing anatomy can do to help, if it isn't already doing them."Doesn't this suggest that the golfer must already be deploying an intact 'LAFW' before impact to achieve Drive-Hold condition during/after impact (up to P7.2)? DG A golfer can have a stable left wrist alignment between P4 and P7 by using an intact LAFW technique where one maintains a GFLW at all times between P4 and P7, but one cannot have a stable clubface that is square to the clubhead arc between P6 and impact because one has to release PA#3 during that time period in order to square the clubface relative to the clubhead arc during that late downswing time period. A skilled golfer can usually get the clubface square a few inches pre-impact as seen in the following capture images of Adam Scott's downswing.
One cannot predict the angular velocity of the clubshaft with perfect precision post-impact, but it is much easier to maintain an intact LAFW post-impact between P7 and P7.2+ if one comes into impact with an intact LAFW (like Adam Scott). Remember that one can have an intact LFFW pre-impact between P6 and P7 if one maintains a GFLW alignment throughout the entire downswing, but one cannot have an intact LAFW alignment because the left forearm is supinating due to the release of PA#3 during that time period. If one perfects the release of PA#3 then the intact LFFW will naturally become an intact LAFW at impact after the successful completion of the release of PA#3. Then, one should be able to maintain an intact LAFW between P7 and P7.2+ if one is swinging rhythmically where one can perfectly match the angular velocity of the left arm relative to the angular velocity of the clubshaft during the early followthrough.
Jeff.
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Post by dubiousgolfer on Jan 16, 2020 21:15:45 GMT -5
Many thanks Dr Mann
DG
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Post by dubiousgolfer on Jan 16, 2020 23:14:40 GMT -5
Dr Mann
I think we've looked at the below video before but if you look closely at 2:34 you will note that Jonas Blixt has lead hand flexion at impact -8.52 degrees. But if you look at 2:26 it shows Jonas as P7.2 and his flexion is -7.87 degrees, his clubshaft has not bypassed his lead arm and he is obviously a 'Drive Holder' where the change in his degree of flexion between impact and P7.2 is 0.65 degrees. So this video provides some extra validation of your Drive-Hold theories.
We've looked at Rickie Fowler's swing before and you commented below:
"DG,
I now believe that I am wrong to imply that Rickie Fowler is using a DH-hand release action (delayed full-roll subtype) in those capture images. He is barely (questionably) maintaining an intact LAFW to P7.2 (image 4) and then the clubshaft clearly bypasses his left arm due to too much left forearm supination after P7.2 - so he is really a borderline DHer, and he actually looks much closer to a non-DHer like Luke Donald.
Jeff."
It looks like you were correct when one sees how large RF's 'Grip Roll' measurement is on Gears at impact compared to Jonas. Also if you look at 2:19 and then 2:26 , you will notice that RF has moved from '-7.67 degrees flexion' at P6.7 to 'extension +7.59' just before P7. Doesn't this means that RF is flipping approaching impact?
DG
PS. I still find the metrics they used for defining 'Clubhead Closure Rate' confusing on Gears even after reviewing it several times and asking Michael Neff (he never replies back to my you-tube comments). I cannot intuitively separate 'Clubhead Closure Rate' from 'Grip Roll' and why its value is so much smaller. I could understand it if the metric was rotation relative to clubhead path per unit of travel (but they just say rotation of club relative to clubhead path).
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Post by imperfectgolfer on Jan 17, 2020 0:05:52 GMT -5
Dr Mann I think we've looked at the below video before but if you look closely at 2:34 you will note that Jonas Blixt has lead hand flexion at impact -8.52 degrees. But if you look at 2:26 it shows Jonas as P7.2 and his flexion is -7.87 degrees, his clubshaft has not bypassed his lead arm and he is obviously a 'Drive Holder' where the change in his degree of flexion between impact and P7.2 is 0.65 degrees. So this video provides some extra validation of your Drive-Hold theories. We've looked at Rickie Fowler's swing before and you commented below: "DG, I now believe that I am wrong to imply that Rickie Fowler is using a DH-hand release action (delayed full-roll subtype) in those capture images. He is barely (questionably) maintaining an intact LAFW to P7.2 (image 4) and then the clubshaft clearly bypasses his left arm due to too much left forearm supination after P7.2 - so he is really a borderline DHer, and he actually looks much closer to a non-DHer like Luke Donald. Jeff." It looks like you were correct when one sees how large RF's 'Grip Roll' measurement is on Gears at impact compared to Jonas. Also if you look at 2:19 and then 2:26 , you will notice that RF has moved from '-7.67 degrees flexion' at P6.7 to 'extension +7.59' just before P7. Doesn't this means that RF is flipping approaching impact? DG PS. I still find the metrics they used for defining 'Clubhead Closure Rate' confusing on Gears even after reviewing it several times and asking Michael Neff (he never replies back to my you-tube comments). I cannot intuitively separate 'Clubhead Closure Rate' from 'Grip Roll' and why its value is so much smaller. I could understand it if the metric was rotation relative to clubhead path per unit of travel (but they just say rotation of club relative to clubhead path). You are correct to infer that RF is flipping just before impact. Look at the following video. Stop the video at the 2:44 minute time point and you will see that RF's left wrist is extending through impact. So, The GEARS figures for RF may be accurate because RF adopts a neutral left hand grip (2 knuckles and borderline 3 knuckles [which is only slightly strong]). However, the GEARS figures for Jonas Blixt are worthless because he adopts an ultra-strong left hand grip and he does not come into impact like the GEARS avatar (which has the back of his left wrist facing the target). The back of JB's left wrist faces the ball-target line at impact, and any left wrist flexion values are roughly happening perpendicular to the ball-target line. Here is the proof!
Here are capture images from that video. Image 1 shows his ultra-strong (4-knuckle) left hand grip at address. Image 2 shows that the back of his left wrist/hand is perpendicular to the ball-target line at P6.5.
Image 3 shows that the back of his left wrist /hand is nearly perpendicular (about ~70 degrees angled) to the ball-target line at impact.
By comparing image 3 to image 2 one can see that he uses very little PA#3 release action in his later downswing, so it is not surprising that he has lower clubface ROC figures during the late downswing and at impact (compared to RF).
One cannot use the small changes in left wrist flexion values between P7 and P7.2 to infer that he is a DHer and would need to use his left wrist ulnar deviation values to show that he does not have significantly more ulnar deviation at P7.2 compared to P7 to infer that he may be a DHer.
Jeff.
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Post by dubiousgolfer on Jan 17, 2020 7:10:20 GMT -5
Many thanks again Dr Mann - another example of GEARS avatars not representing reality.
I can see Jonas's 'wrist cock' angle at 2:18 being '23 degs 45 secs' (P7) and '21 deg 45 secs' at 2:23 (P7.2)
So a change of 2 degrees less wrist cock from P7- P7.2 .
DG
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Post by dubiousgolfer on Jan 17, 2020 7:54:23 GMT -5
Even stranger figures seen on this video for Curtis Thompson.
It looks like he has zero Grip Roll and Clubhead Closure rate through P7 to P7.3 (at 9:10- 9:15). At P7 Grip Roll was 1799.43 deg/s , Closure Rate 529.74 deg/s but then reduces almost instantaneously to zero post impact.
The same happened when he included an Avatar of RF's swing at 8:33 (zero 'Grip Speed/Grip Roll/Closure Rate' at P7). Maybe an error in Gears!
DG
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Post by dubiousgolfer on Jan 20, 2020 20:29:27 GMT -5
More instances of Gears showing zero Clubhead Closure Rate and Grip Roll (see 3:42 and 3:43 for Chris Baker swing)
Just wondering (providing no error in Gears) if this proves that some of these PGA pros are actually square to the clubhead path through impact
DG
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Post by imperfectgolfer on Jan 21, 2020 0:52:09 GMT -5
More instances of Gears showing zero Clubhead Closure Rate and Grip Roll (see 3:42 and 3:43 for Chris Baker swing) Just wondering (providing no error in Gears) if this proves that some of these PGA pros are actually square to the clubhead path through impact DG I personally do not trust that the GEARS system can actually measure the instantaneous grip roll and clubface ROC at impact precisely enough because the GEARS system apparently samples at a sampling rate of ~450Hz, which I think is not fast enough. I suspect that an accurate measurement of instantaeous grip roll/clubface ROC at impact would require a sampling rate in the 5,000 - 10,000 Hz range. Jeff.
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Post by dubiousgolfer on Jan 21, 2020 5:23:46 GMT -5
Many thanks Dr Mann - I should have remembered that Gears also had sampling rate issues to measure rate of forearm rotation which obviously has relevance to 'Grip Roll' and 'Clubface Closure Rate' metrics too. Just seen another Russell Heritage video below regarding 'Twistaway' and find it baffling. DG PS. Does he really mean using "early left forearm supination + left wrist palmar flexion" rather than 'Twistaway' (clenching/torqueing the fingers around the grip)? I think he is implying it is required to be a DHer (including a right pitch elbow although he fails to include right shoulder shoulder downplane and right lateral flexion). I think RH may be using KM's articles below kelvinmiyahiragolf-articles.com/index.php/articles/articles-2/2013-articles/30-2013-12-essentials-of-the-drive-hold-swingRH promoting supination of right forearm while also supination of left forearm which I think is impossible (if keeping a secure grip). To suggest that tour golfers regrip is not something I have seen too often, although I've seen VJ Singh and PM loosen their rear hand grip (run out of right arm?).
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