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Post by imperfectgolfer on Jun 7, 2012 7:15:59 GMT -5
I am increasingly convinced that Jeffy doesn't understand what the terms "pronation" and "supination" signify. I wrote-: "One possibility is that Hogan was applying a wrist torque in the opposite direction during his downswing action to reverse the wrist torque that he imposed at his end-backswing position, and that biomechanical wrist torquing action prevented the cluface from becoming square by impact." Jeffy then wrote-: "Ah, sounds like early supination to me!!!" I think that he is misusing the term "supination" to imply left wrist arching due to left wrist dorsiflexion. However, supination is a forearm rotary motion and not a wrist motion - and Jeffy is making the same mistake as Hogan who misused the terms "supination" and "pronation" as being wrist motions. A forearm rotary motion doesn't affect the wrist and the wrist and hand undergo the same degree of rotation when the forearm rotates. See the following glossary for further details. perfectgolfswingreview.net/wrist.htmJeff.
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Post by tomdavis76 on Jun 7, 2012 8:42:50 GMT -5
Tom, because it doesn't that's why. Why does it have to? For the same reason that "lack of right wrist extension" causes the shaft to cross the line! Left wrist extension and right wrist flexion produce the same result.
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Post by tomdavis76 on Jun 7, 2012 9:05:32 GMT -5
Jeffy wrote-: "Obviously the above response is simply make-believe: you have no way of knowing that Hogan is "employing the equivalent of a twistway maneuver" (dorsflexion of the right wrist and pronation of the right forearm) and, even if he did, that would simply remove the cup in the left wrist and supnate the left forearm!" I think that Jeffy is clueless about what I mean by a twistaway action. It has nothing to do with the right forearm/wrist or the left forearm, and it happens solely due to left wrist/finger motion. Here is what I mean by a twistaway action. When Hogan dorsiflexes his left wrist more, he is simultaneously using his fingers which are curled around the grip to rotate the clubshaft about its longitudinal axis - so that the fixed red point on the grip rotates clockwise. It is purely a left wrist/hand motion and it doesn't involve any left forearm motion. Any movement of the right wrist/hand occurs secondary to the motion of the left hand and there is no change in right forearm alignment/motion. It is very simple for any forum member to understand my viewpoint - by simply performing the Hogan "secret move" action at home. Simply adopt a neutral left hand grip and get to an end-backswing position with a GFLW and without the right hand attached to the grip. Then simply dorsiflex your left wrist and simultaneously twist the club about is longitudinal axis using your fingers which are curled around the grip. Note that you are not moving your left arm/forearm during this twisting action. You should be able to see your finger knuckles at the proximal interphalangeal joints move upwards in a rotary manner, and the clubface should rotate to exactly the same degree because you are torquing the club with your fingers which are curled around the club. The clubface should rotate to a more open position and the toe of the club will point more downwards. Then repeat the experiment with your right hand attached in the typical manner - but keep your right forearm/elbow stationary at their end-backswing RFFW positional alignment and allow the right wrist to passively palmar flex in response to the left wrist/hand motion. You have it exactly backwards. Manzella, who coined the term "twistaway", defines it as the opposite set of movements: left wrist palmar flexion/right wrist extension and left forearm supination/right forearm pronation. And the red dot above is moving simply because of the left wrist dorsiflexion, not because the fingers are twisting the shaft longitudinally. I think there is a small difference in left forearm rotation, commensurate with the modest amount of cupping. The Manzella illustration is very misleading if not outright wrong. This is how golf biomechanists define the different movements: jeffygolf.com/showthread.php?166-How-Biomechanists-Define-MovementsWrist extension and flexion control movement around the x-axis, wrist ulnar and radial deviation control movement around the y-axis, and forearm supination and pronation (as well as shoulder internal and external rotation) control movement around the z-axis. Actually, you are simply confused and I am correct. The clubface "opening and closing" relative to the left forearm is controlled by wrist flexion and extension, and influences the loft of the clubface, not the face angle relative to the path. Only forearm supination and pronation and shoulder internal and external rotation influence the face angle relative to the path. So, in your example, since the wrist stays intact, the clubface will not move relative to the forearm even though it has been opened relative to the path.
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Post by tomdavis76 on Jun 7, 2012 9:25:11 GMT -5
I am increasingly convinced that Jeffy doesn't understand what the terms "pronation" and "supination" signify. I wrote-: "One possibility is that Hogan was applying a wrist torque in the opposite direction during his downswing action to reverse the wrist torque that he imposed at his end-backswing position, and that biomechanical wrist torquing action prevented the cluface from becoming square by impact." Jeffy then wrote-: "Ah, sounds like early supination to me!!!" I think that he is misusing the term "supination" to imply left wrist arching due to left wrist dorsiflexion. However, supination is a forearm rotary motion and not a wrist motion - and Jeffy is making the same mistake as Hogan who misused the terms "supination" and "pronation" as being wrist motions. A forearm rotary motion doesn't affect the wrist and the wrist and hand undergo the same degree of rotation when the forearm rotates. See the following glossary for further details. perfectgolfswingreview.net/wrist.htmJeff. Nope, I understand these terms as well as if not better than you do. As far as Hogan "misusing" supination and pronation, that is debatable. It seems clear to me from the illustrations in Five Lessons, as well as the text of the Life article, that Hogan thought of supination/palmar flexion and pronation/extension as going together in a golf swing and didn't bother to go into complete detail. It is also possible that Herbert Warren Wind didn't fully understand this and, as a result, didn't describe the movements 100% correctly. Wind, presumably, was responsible for a few whoppers in Five Lessons and the Life article (which he also ghosted), including mistaking 1946 for 1947 as the year Hogan discovered the "secret", mistaking a 2-iron for the 1-iron that Hogan hit into the 72nd hole at Merion in 1950, and saying that Hogan was left-handed, despite this illustration towards the end of the book!:
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Post by golfpro on Jun 7, 2012 9:52:32 GMT -5
Tom, because it doesn't that's why. Why does it have to? For the same reason that "lack of right wrist extension" causes the shaft to cross the line! Left wrist extension and right wrist flexion produce the same result. You said left wrist dorsiflexion BY ITSELF causes the shaft to cross the line. It doesn't. I already said the right arm/hand have to be involved for the shaft to get across the line.
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Post by imperfectgolfer on Jun 7, 2012 15:56:31 GMT -5
Jeffy,
You wrote-: "You have it exactly backwards. Manzella, who coined the term "twistaway", defines it as the opposite set of movements: left wrist palmar flexion/right wrist extension and left forearm supination/right forearm pronation."
That's factually correct - seeing that BM first used the term "twistaway". You can then label Hogan's "secret move" as a "reverse-twistaway" action, but I believe that it has the same basic feature of a torquing of the club around its longitudinal axis (but simply in the opposite direction).
You wrote-: "And the red dot above is moving simply because of the left wrist dorsiflexion, not because the fingers are twisting the shaft longitudinally."
The pattern/degree of red dot moving will obviously be different if one bends (dorsiflexes) the left wrist thereby causing the club to angulate significantly and cross-the-line - compared to Hogan's "secret move" where he doesn't change the clubshaft angle, but applies a certain amount of torque on the near-stationary grip with his fingers.
You wrote-: "Actually, you are simply confused and I am correct. The clubface "opening and closing" relative to the left forearm is controlled by wrist flexion and extension, and influences the loft of the clubface, not the face angle relative to the path."
I disagree! I think that any left wrist extension/flexion through the impact zone angulates the clubshaft and it changes all the alignments (path and clubface) to a variable degree - depending on the accumulator #3 angle through the impact zone.
Jeff.
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Post by imperfectgolfer on Jun 7, 2012 16:24:51 GMT -5
Jeffy, I looked at this thread that you started. jeffygolf.com/showthread.php?166-How-Biomechanists-Define-Movementsi personally think that defining the movements like Rob Neal has even less utility than BM's descriptions (which I find near-useless). For example, you wrote-: "Flexion and extension of the wrists affect the x-axis and therefore control the loft". That only applies at one point-in-time - when the hands are near/at impact and when the clubshaft is perpendicular to the ball-target line. It doesn't apply at other time points in the backswing, downswing and followthrough. You also wrote-: "Radial and Ulnar deviation occur in both wrists at the same time -- These movements occur in the y-axis and affect the shaft angle or plane when viewed from the target line". I think that's nonsensical because one never performs a golf swing motion - as demonstrated by this photo. It is correct to state that she is both radially deviating her left and right wrist at the same time - and in the same vertical plane. However, that is not a golf swing motion. Here is Martin Hall demonstrating his backswing action with metal hinges attached to his lower arms/hands - and where his left wrist is radially deviating while his right wrist dorsiflexes. perfectgolfswingreview.net/HallMidBackswing.jpg [/img] Only the left wrist is radially deviating, and it is not in a Y-plane. You wrote-: "Supination and Pronation affect the z-axis or the axial rotation of the shaft. As long as there is rotation in the ulna and radial bone, there is going to be either supination or pronation occurring. From the scientific world, these are the only movements that cause axial rotation of the shaft". I believe that supination/pronation only produce a pure axial rotation if one zeroes-out the accumulator #3 angle and if one keeps the clubshaft stationary during the rotary motion. That doesn't happen in most golfers. I think that a "true" axial rotation is more likely to occur when the fingers torque the club about its longitudinal axis in a stationary (or near-stationary) hand eg. at the end-backswing position when Hogan performs his "secret move" maneuver. This is Tapio's photo-demonstration. You wrote-: "While thinking you are demonstrating only left wrist flexion, you are axially rotating the shaft. Therefore there is left forearm supination and right forearm pronation." I can see no evidence of left forearm supination - the watchface area on his lower left forearm has not changed its orientation. The axial rotation of the shaft is due to his finger-torquing action - which happens simultaneously while he actively palmar flexes his left wrist. Jeff.
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Post by golfpro on Jun 7, 2012 17:17:18 GMT -5
Jeff, Using the pic above of Hogan's hands as an example, how do you move the red dot without any wrist movement? Didn't the red dot move in that pic because the left wrist dorsiflexed? I can do it if I let the heel pad and palm of the left hand come off the club and curl the handle up and down in the fingers going from a closed fist to open hand position. If I maintain the closed fist and the heel pad stays on the handle, I have to use wrist extension to get the club to rotate on it's own axis. The pattern/degree of red dot moving will obviously be different if one bends (dorsiflexes) the left wrist thereby causing the club to angulate significantly and cross-the-line Jeff. I also would like to see how left wrist dorsiflexion BY ITSELF without any other influences being applied to the handle will significantly angulate the shaft across the line. Thanks
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Post by tomdavis76 on Jun 7, 2012 21:59:55 GMT -5
Jeffy, I looked at this thread that you started. jeffygolf.com/showthread.php?166-How-Biomechanists-Define-Movementsi personally think that defining the movements like Rob Neal has even less utility than BM's descriptions (which I find near-useless). For example, you wrote-: "Flexion and extension of the wrists affect the x-axis and therefore control the loft". That only applies at one point-in-time - when the hands are near/at impact and when the clubshaft is perpendicular to the ball-target line. It doesn't apply at other time points in the backswing, downswing and followthrough. First point: Kelvin wrote it; I simply posted it for him. Second, I think your opinion is just plain wrong. [/img] Only the left wrist is radially deviating, and it is not in a Y-plane.[/quote] Your quarrel is with the golf biomechanists, not me or Kelvin. In any case, I happen to think you're just blowing hot air. Honestly, believe whatever you want. I think you are just flat out wrong, though. Sure, believe whatever nonsense you want. Here is a similar demonstration that measures the left forearm supination in this instance as being in the range of 30 to 40 degrees: Here is a better angle to view Tapio's left forearm motion and, as you can see, it is rotating a bunch, almost 60 degrees.
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Post by tomdavis76 on Jun 7, 2012 22:01:35 GMT -5
For the same reason that "lack of right wrist extension" causes the shaft to cross the line! Left wrist extension and right wrist flexion produce the same result. You said left wrist dorsiflexion BY ITSELF causes the shaft to cross the line. It doesn't. I already said the right arm/hand have to be involved for the shaft to get across the line. OK, we'll just agree to disagree, then.
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Post by imperfectgolfer on Jun 7, 2012 23:00:07 GMT -5
GolfPro, You asked-: "Using the pic above of Hogan's hands as an example, how do you move the red dot without any wrist movement? Didn't the red dot move in that pic because the left wrist dorsiflexed?" Of course the red dot is moved due to left wrist dorsiflexion. However, the dorsiflexion of the left wrist is significantly due to activation of the finger extensor muscles/tendons. The activation of the finger extensor muscles applies a rotary torque to the club if the fingertips are curled around the grip. That produces a certain pattern of movement of the red dot that is different to what would happen if the fingertips are not curled around the grip and if the fingers are extended. To assess that assertion, get to an end-backswing position with a GFLW/intact LAFW => do the simple experiment of holding the grip against the left palm with the right hand (in order to stabilise the grip against the left palm) but keep the fingers extended. Then dorsiflex the left wrist => you will note that there is less of a rotary motion of the red dot due to the absence of any fingertip curling torque. You asked-: "I also would like to see how left wrist dorsiflexion BY ITSELF without any other influences being applied to the handle will significantly angulate the shaft across the line." It is simple to demonstrate - using a neutral grip, get to an end-backswing position so that you have a GFLW and intact LAFW and make sure that the clubshaft is parallel to the ball-target line. Then remove your right hand from the club => then dorsiflex the left wrist. The absence of the right hand (which normally restrains the movement of the club) will allow the clubshaft to angulate and the angulation will cause the clubhead to cross-the-line (because a greater proportion of the dorsiflexion motion occurs near the scaphoid bone on the radial side of the wrist joint - relative to the ulnar side of the wrist joint). perfectgolfswingreview.net/wristmovement.jpg [/img] The prime area of wrist motion occurs between the distal radius and the scaphoid wrist bone and less between the distal radius and the lunate wrist bone, and far less between the distal ulna and the triquetrium wrist bone. It is that relative disparity-of-motion that causes angulation - in the absence of secondary constraining factors that limit clubshaft motion (eg. position of the right palm). Jeff.
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Post by imperfectgolfer on Jun 7, 2012 23:29:46 GMT -5
Jeffy, You wrote in response to three claims that I made-: "Second, I think your opinion is just plain wrong." --- "Your quarrel is with the golf biomechanists, not me or Kelvin. In any case, I happen to think you're just blowing hot air." ---- "Honestly, believe whatever you want. I think you are just flat out wrong, though." It does not surprise me that you disagree with me and that you think that I am plain wrong. However, I think that the absence of a strong evidence-based counterargument on your part speaks volumes re: the validity of your contrary opinions. In the jeffy-forum, forum members get banned for adopting that type of argumentative approach. Consider the Tapio photo. You wrote regarding the Tapio photo-: "Here is a better angle to view Tapio's left forearm motion and, as you can see, it is rotating a bunch, almost 60 degrees." The red lines are not measuring the change in rotary angulation of the left hand that is solely due to a forearm rotary motion - because there is significant independent wrist motion happening at the same time as the left wrist moves from dorsiflexion to palmar flexion. Most of the 57 degrees of angular change is due to left wrist motion and not left forearm motion. If you truly want to measure the degree of left forearm supination, then the red lines should be drawn at the level of the dorsum of the left lower forearm about 2" above the radiocarpal wrist joint (where one normally situates a watchface). It is visually obvious that there is far less (almost negligible) rotary/supinatory angulation happening at the level of the lower forearm. To better perform the Tapio demonstration, Tapio should grasp his left lower forearm with his right hand in order to prevent any rotary motion of his left lower forearm => then he should perform the same active/forceful left palmar flexor motion. The results will be the same - the clubshaft will not angulate but the clubface will become more closed due to axial rotation of the clubshaft around its longitudinal axis that is not due to any forearm supinatory motion. Any forum member can independently do this experiment at home. Jeff.
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Post by golfpro on Jun 8, 2012 0:16:57 GMT -5
You said left wrist dorsiflexion BY ITSELF causes the shaft to cross the line. It doesn't. I already said the right arm/hand have to be involved for the shaft to get across the line. OK, we'll just agree to disagree, then. Tom, I hate doing that! lol I can hold a club only with my left hand in a top of the backswing position with a FLW and then dorsiflex my left wrist and the club doesn't angulate at all. Zip, zilch, nada. If anything the club wants to fall downward (gravity & weakness) and behind me because as I said before, when you dorsiflex the left wrist the left forearm has a tendency to want to pronate.
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Post by golfpro on Jun 8, 2012 0:55:15 GMT -5
It is simple to demonstrate - using a neutral grip, get to an end-backswing position so that you have a GFLW and intact LAFW and make sure that the clubshaft is parallel to the ball-target line. Then remove your right hand from the club => then dorsiflex the left wrist. The absence of the right hand (which normally restrains the movement of the club) will allow the clubshaft to angulate and the angulation will cause the clubhead to cross-the-line (because a greater proportion of the dorsiflexion motion occurs near the scaphoid bone on the radial side of the wrist joint - relative to the ulnar side of the wrist joint). Jeff, As I said to Tom above, I've done what you suggest here, and when I do it, the club does not angulate forward at all. It actually wants to move in the apposite direction for the reason I mentioned above (tendency of left forearm to pronate when left wrist is dorsiflexed). Your experiment of holding the club against the left palm with extended fingers seems frivolous. If you could hold the club in the left hand with a normal grip and then make the red dot rotate without any wrist movement whatsoever, then I would be impressed.lol Of course the fingers wrapped around the handle play a part in controlling the clubface. Example, exerting different pressures with the fingers tighter or softer can affect varying results.
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Post by tomdavis76 on Jun 8, 2012 7:29:10 GMT -5
Jeffy, You wrote in response to three claims that I made-: "Second, I think your opinion is just plain wrong." --- "Your quarrel is with the golf biomechanists, not me or Kelvin. In any case, I happen to think you're just blowing hot air." ---- "Honestly, believe whatever you want. I think you are just flat out wrong, though." It does not surprise me that you disagree with me and that you think that I am plain wrong. However, I think that the absence of a strong evidence-based counterargument on your part speaks volumes re: the validity of your contrary opinions. In the jeffy-forum, forum members get banned for adopting that type of argumentative approach. If you choose to concoct your own arbitrary interpretations of golf biomechanics, I'm not sure what "evidence" would have any influence on you. I have better uses for my time. Before you said there was "no" forearm rotation in Tapio's demonstration, now you at least admit there is "some" but want to quibble about the amount and how much is from palmar flexion, etc. Again, you are just creating arbitrary interpretations of the available evidence so there is no point to further discussion.
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