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Post by imperfectgolfer on May 19, 2012 9:26:48 GMT -5
Consider this BM-diagram. It demonstrates that BM doesn't understand left wrist motion through the impact zone. Note that he is drawing violet-colored lines to demonstrate the degree of left wrist bend through the impact zone. The lines are correctly drawn pre-impact - because they represent the degree of left wrist bend in the plane of left wrist flexion-extension (palmar flexion - dorsiflexion). However, he has drawn the post-impact lines in the plane of ulnar-radial deviation and that represents the degree of cocking of the left wrist, and not the degree of left wrist bend (dorsiflexion). The reality is that Hogan's (and most PGA tour golfers) left wrist is flat betweeen P7 and P7.5, and there is no bending in the plane of flexion-extension. I have no idea why he believes that there is gamma torque on the shaft in Hogan's swing action. Where have you ever seen a professional golfer's club twisting about its longitudinal axis as it goes through impact - if they do not use an AJ Bonar type of hand-crossover release action. AJ Bonar hand crossover release action. I would also like to see any forum member explain when a golf club is being torqued off-plane (beta torque) during the downswing. Jeff.
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Post by gmbtempe on May 21, 2012 10:02:24 GMT -5
Jeff,
Was getting a bit worried when you disappeared, glad your still around posting.
Will review your posts tonight.
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Post by imperfectgolfer on May 21, 2012 19:40:54 GMT -5
Greg,
I am still around, but I have very little incentive to post anymore. There are very few broad-minded golfers (like you), who are genuinely interested in different ideas re: golf swing mechanics/biomechanics, and who are still participating in golf forums. Most of the active golf forum members (eg. in Jeffy's/BM's golf forums) have very polarised viewpoints and some forum members (like Footwedge in the "Jeff Mann" subsection of the Goltham Golf forum) are only capable of very vulgar ad hominem attacks. I am flabbergasted at the vulgarity of his ad hominem attacks on Tapio and his tendency to use expletives in vulgar ad hominem attacks. There are many others like him, who make golf forum participation a futile exercise in gross vulgarity - and their posts are also simultaneously devoid of any serious intellectual content.
I now only only plan to post infrequently - in order to occasionally point out the intellectual weaknesses of posts by Jeffy/KM and BM/BM groupies.
Jeff.
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Post by imperfectgolfer on May 22, 2012 20:46:27 GMT -5
Here is a photo from BM"s forum. In image 1, note how BM is palmar flexing his left wrist. Normally that will angulate the clubshaft backwards, but BM is preventing that from happening by pushing with his RFFW/right hand to get the club to become straight-aligned with the left arm. That biomechanical phenomenon can only happen if he simultaneously supinates his left forearm and twists the club in his left hand. That "maneuver" causes the watch-area on the back of the lower left forearm to move away from the body, while he is applying a gamma torque to the club. Note that the golfer in image 2 has a neutral left wrist (FLW) and an intact LAFW. That causes the toe of his club to point straight upwards as the clubface is parallel to the back of his FLW, and the clubface is not closed to the clubhead arc due to the application of a twisting (gamma) torque. From that P6 position, the club will continue to release within the plane of the LAFW, and he will square the club later in the downswing (between P6.7 and P7) via the release of PA#3 - and during this PA#3 release action, he will not have to apply a gamma twisting torque to close the clubface to the clubhead arc so that the clubface can become square by impact. The clubface will simply rotate to square as the FLW rotates to square. Jeff.
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Post by imperfectgolfer on May 25, 2012 9:24:25 GMT -5
BM wrote today in his forum-: "The big ramp up of z axis rotation starts between left arm level and shaft level on the downswing." BM is talking about between P5 and P6. Look at this photo-diagram produced by BM. How could a golfer produce that gamma torque between P5 and P6 and cause the clubshaft to twist about its longitudinal axis so that the clubface becomes closed to the clubhead arc - without affecting the clubshaft angle. It would require Tapio's maneuver (what BM calls a twistaway maneuver) - which is biomechanically due to a "forced" left wrist palmar flexion action. That is not happening in Hogan's swing. He has a GFLW between P5 and P6 and there is no left wrist palmar flexion happening during the mid-downswing. perfectgolfswingreview.net/HoganPowerPackageSlotting.jpg [/img] I also don't think that a golfer should apply a beta torque at that time in order to rotate the clubshaft counterclockwise. If a golfer supinated his left forearm between P5 and P6, then the clubshaft would steepen. That doesn't happen in Hogan's swing. Image 3 of the Hogan sequence represents P5 and image 5 is when he is approaching P6. Note that the back of his GFLW remains parallel to the mid-downswing clubshaft plane and there is no rotation of his GFLW due to a left forearm rotary motion - note that the clubshaft doesn't steepen between P5 and P6. Jeff.
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Post by imperfectgolfer on May 25, 2012 9:48:46 GMT -5
See this BM-thread. www.brianmanzella.com/golfing-discussions/17245-understanding-xyz-axes-what-contributes-most-clubhead-speed.htmlKevin wrote-: "How can beta not have an effect on clubhead speed? The force across the shaft out of the hand plane would make the clubhead fly to the ball." He believes that a beta torque is due to a "force-across-the-shaft" that is out-of-the-hand plane. Wow! Since when did BM refer to a hand plane as a reference point? Also, when have you seen the clubshaft change planes between P5.5 and P7 in a good golfer? Drew wrote in that same thread-: "I think that "fast closure rates contribute to y-axis rotation" is equivalent to saying that "fast closure rates" i.e. greater twisting of the grip along the axis of the shaft (gamma) accelerates the rotation about the coupling point, i.e. bottom of grip passing top grip or, in Enso speak, y-axis acceleration. To me it is intuitive that twisting the grip on the way down will accelerate the y-axis velocity. So let's grab a club. Let the arms drop from the top with no twisting. Now let the arms drop with twisting. Feel acceleration?" Crazy! How can one believe that one can accelerate the release of PA#2 due to the application of a rotary twisting force that causes the clubshaft to twist about its longitudinal axis. An active "rotation-about-the-coupling point" action normally operates in the plane of left wrist uncocking - the plane of what BM now calls the Y axis. Jeff.
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Post by imperfectgolfer on May 25, 2012 10:02:29 GMT -5
BM wrote-: "a. Clubface on a table top, clubface vertical to the table at "address," body straight up and down, normal stading attitude.. 20 inch scrape backswing, 40 inch forward swing. Score lines of the FACE stay 90 degrees to the table. ZERO z axis/GAMMA rotation.
b. Clubface on a table top, clubface vertical to the table at "address," body straight up and down, normal standing attitude. On the 20 inch scrape backswing face opens 30 degrees. On the 40 inch forward swing the face closes 60 degrees and finishes 30 degrees closed to the table. There is OBVIOUS z axis/GAMMA rotation. We will call the amount (which is dependent on the speed) XXX amount.
c. Clubface on a table top, clubface vertical to the table at "address," body straight up and down, normal standing attitude. On the 20 inch scrape backswing face opens 30 degrees. On the 40 inch forward swing the face rotates the EXACT same amount that caused the face to rotate 60 degrees to the table and finished 30 degrees closed to the table. THE SAME EXACT XXX z axis/GAMMA rotation. But....the golfer slides the tailbone a hair forward, open the hips a bunch, the shoulders a decent amount, adds right side bend, moves toward back extention......The face does not rotate as much to the table. "
In example c, how does body motion affect the degree of clubface rotation if it measures the same - relative to the reference point of the table top?
BM doesn't seem to understand that any Z-axis rotation between P6.5 and P7 doesn't have to happen uniformly throughout that range. I think that a good golfer (who uses a DH release) doesn't have any gamma axis rotation between P6.9 and P7.1.
Jeff.
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Post by imperfectgolfer on May 26, 2012 9:18:13 GMT -5
Consider this BM video. vimeo.com/42840983In this video, BM claims that Hogan was twisting the shaft about its longitudinal axis between P5 and P6, and he also stated that this application of a twisting torque increases clubhead speed. He has presented ZERO evidence to support those beliefs. How could any application of a gamma torque between P5 and P6 increase clubhead speed? The second question becomes - did Hogan actually twist-torque the club in his downswing, and when did he perform that action (between P5 and P6 or between P6 and P6.5)? Jeffy posted this comparison photo. Jeffy wrote-: "See any early "twist" pre-secret, on the left? Plenty post-secret, on the right." What is Jeffy seeing differently in those two animated gifs? Where is there visual evidence that Hogan is twist-torquing the club (and applying gamma torque) in the second animated gif image and not the first animated gif image? Jeffy has also previously posted this animated gif of Hogan's swing. i223.photobucket.com/albums/dd102/jeffy10028/Supinate-PFGIF.gif [/img] In this sequence one can see that the clubface is more closed to the clubhead arc at P6-6.5 than it was at P5.5. So, one can accept that Hogan was applying a gamma torque in this swing sequence. However, does that represent his routine practice? It could well be that Hogan was palmar flexing his left wrist earlier than usual in that particular swing. Where is there additional visual evidence that this was Hogan's routine pattern - considering that he never mentioned this maneuver in his Five Lessons book? In his book, he described (using the diagram in the first post of this thread) that he moved from a GFLW (lsightly cupped left wrist) to an anatomically flat left wrist between P5.5 and P6.5 and that he moved from a flat left wrist to an arched left wrist between P6.5 and P7. Jeff.
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Post by imperfectgolfer on May 26, 2012 16:38:20 GMT -5
Greg,
You wrote the following in BM's forum-: "I think this is the key move in a good golf swing, one I had previously thought could not be taught but I was wrong."
What is the key move? Why is it a key move?
Jeff.
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Post by tomdavis76 on May 28, 2012 21:15:10 GMT -5
Here is 1966 Hogan v. pre-secret 1947 Hogan. Early PF and supination is pretty obvious post-secret. TD
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Post by imperfectgolfer on May 28, 2012 21:32:52 GMT -5
Consider this BM video. vimeo.com/42840983BM states that a golfer is applying gamma torque to the club between P5 and P6 (via a twistaway maneuver) and that the twistaway action will close the clubface to the clubhead arc. He also claims that the twistaway action will increase clubhead speed at impact - although he provides no evidence to support his claim. In his video, he states that he consulted Sasho MacKenzie, but he doesn't state exactly what SMK stated. Here is SMK's research paper on the subject. people.stfx.ca/smackenz/Publications/MacKenzie%202012%20Club%20position%20relative%20to%20the%20golfer%27s%20swing%20plane%20meaningfully%20affects%20swing%20dynamics.pdfIn this research paper, SMK states that active left forearm supination (via the application of a left forearm rotary torque) will increase clubhead speed at impact by 22%. However, when you read the paper you will note that the active left forearm torque in his forward dynamics computer model is applied at 0.16 seconds into the downswing. Here is the graph from the paper. Note that the left forearm supinatory torque is applied between 0.16 seconds and 0.25 seconds, and that represents the release of PA#3 that occurs in the late downswing (between P6 and P7). Note that left wrist ulnar deviation (representing the release of PA#2) occurs before the release of PA#3. Note that no gamma (left forearm supinatory torque) is applied between P5 and P6. If the left forearm supinatory (gamma) torque is started when the club bypasses P6, when does the clubshaft actually undergo a rotary (gamma) motion? It happens between P6.5 and P7 (impact). Consider David Toms' swing. Image 1 shows DT at address - note that he has a strong left hand grip due to i) internal rotation of his left humerus (which causes his antecubital fossa to face away from the target) and ii) left forearm pronation. To have a square clubface at impact (image 4), he must have the same anatomical alignments - i) internal rotation of his left humerus (which causes his antecubital fossa to face away from the target) and ii) left forearm pronation. Note how much you can see of the glove logo on the back of his left hand in image 1 and image 4. Note that the back of his left hand is parallel to the ball-target line in image 2 - when he is roughly at P6.5. Note that the clubface is open to the ball-target line. In other words, he hasn't released PA#3 at P6.5. Image 3 shows him at P6.7. Note that his glove logo and clubface are becoming more closed - and this is due to the release of PA#3. One can see the same biomechanical/mechanical phenomena in a DTL view of DT's swing. Image 1 shows him at P5 - note that his clubface is slightly closed relative to the back of his left hand and that is due to his strong grip. Image 2 shows him at P5.5. Note that the clubface is not more closed to the back of his FLW. Note that his FLW is parallel to his mid-downswing's inclined plane. Image 3 shows him at P6. Note that the toe of the club is pointing upwards. Note that there is no closing of the clubface (compared to image 2) because he is not applying a twistaway gamma torque to the club. Note that the back of his FLW is still parallel to his mid-downswing's inclined plane. Image 4 shows him at ~P6.5. Note how he is releasing PA#2, and that the club is releasing on-plane - note that the back of his FLW is roughly parallel to the ball-target line. Image 5 shows him at ~P6.7. Note that he has nearly fully released PA#2, but the back of his FLW is still roughly parallel to the ball-target line, which means that he hasn't yet released PA#3 (which is biomechanically due to a left forearm supinatory motion). Image 6 shows him at impact (P7) - note that he has released PA#3 and the back of his FLW is now rotated more towards the target. His FLW will not face the target at impact - because he has a strong left hand grip. Any gamma torque being applied in DT's swing mainly occurs between P6.5 and P7, and it is due to a left forearm supinatory motion, and that represents the release of PA#3. There is no evidence of any gamma (left forearm supinatory torque) occurring between P5 and P6 - as BM claims in his video. Jeff.
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Post by imperfectgolfer on May 28, 2012 23:14:26 GMT -5
TD wrote-: "Early PF and supination is pretty obvious post-secret."
I disagree! The clubface is open to the clubhead arc and the toe of the club is pointing upwards in the second animated gif image. The clubface is parallel to the back of his FLW and it is not closed relative to the back of his FLW. Hogan's clubface is not more closed than David Tom's clubface in image 4 of his DTL sequence.
One cannot see the clubface in the first animated gif image, and the clubshaft is positioned between P5.5 and P6, and not at P6.3 (as in the second animated gif image)
Jeff.
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Post by tomdavis76 on May 29, 2012 20:14:48 GMT -5
TD wrote-: "Early PF and supination is pretty obvious post-secret." I disagree! The clubface is open to the clubhead arc and the toe of the club is pointing upwards in the second animated gif image. The clubface is parallel to the back of his FLW and it is not closed relative to the back of his FLW. Hogan's clubface is not more closed than David Tom's clubface in image 4 of his DTL sequence. One cannot see the clubface in the first animated gif image, and the clubshaft is positioned between P5.5 and P6, and not at P6.3 (as in the second animated gif image) Jeff. A lot of changing the subject going on. What does David Toms have to do with this topic? Your question was whether or not the early PF and supination visible in the 1954 driver sequence was a "one off" or something Hogan did consistently. There aren't many sequences of Hogan that are clear enough to tell, but the 1966 iron at Olympic clearly shows the same left wrist/left forearm action.
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Post by imperfectgolfer on May 29, 2012 21:21:00 GMT -5
TD,
You can believe whatever you want to believe, but I don't think that there is any difference in Hogan's left wrist action between his earlier career and later career. I think that he transitioned from a GFLW => AFLW => arched left wrist as he described in his "Five Lessons" book. Your first animated gif was captured too early - prior to P6. As Hogan described in his book's diagram, the transition from a GFLW to an AFLW happens after P6. I also don't see any unusual clubface closing in the second animated gif due to a twistaway maneuver. The toe of his club is pointing relatively upwards and the clubface is not unusually closed to the clubhead arc in that second animated gif.
Jeff.
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Post by tomdavis76 on May 29, 2012 22:02:53 GMT -5
TD, You can believe whatever you want to believe, but I don't think that there is any difference in Hogan's left wrist action between his earlier career and later career. I think that he transitioned from a GFLW => AFLW => arched left wrist as he described in his "Five Lessons" book. Your first animated gif was captured too early - prior to P6. As Hogan described in his book's diagram, the transition from a GFLW to an AFLW happens after P6. I also don't see any unusual clubface closing in the second animated gif due to a twistaway maneuver. The toe of his club is pointing relatively upwards and the clubface is not unusually closed to the clubhead arc in that second animated gif. Jeff. Show me some pictures pre-secret where he arches the left wrist. Good luck.
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