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Post by imperfectgolfer on Jun 4, 2012 7:35:08 GMT -5
nmg wrote-: "So Mackenzie acknowledges previous research finding the non-planar nature of the golf swing. Then in the next sentence he claims the paper will examine the planar nature of the golf swing! Talk about a contradiction. Why does Mackenzie want to examine that which is acknowledged not to exist? Because the planar problem is easier to solve. BUT ITS WRONG! CONSEQUENTLY THE RESULTS OF THE STUDY ARE MEANINGLESS AND CANNOT BE APPLIED TO A REAL GOLF SWING."
I harbor a totally different opinion. SMK is sufficiently insightful to realize that there is a difference between the left arm plane and the clubshaft plane, and he is also insightful enough to know that there is no constant left arm-hand/clubshaft plane during the downswing. Most golfers are shallowing their plane between P4 and P6 to a varying degree (varying degree between one golfer and the next golfer). However, although the swingplane is not constant in its positional alignment - it is obviously easy to examine the relationship between the clubshaft angle and the left arm/hand angular motion at all time points in the downswing between P4 and P6. I therefore think that his research findings are relevant and not meaningless.
nmg also wrote-: "Jeff needs to prove his assertion that pronation/supination is not modeled by Nesbit. I believe the required d.o.f's to model that motion are indeed there."
I don't need to prove that Nesbit's clubshaft motion modelling is two-dimensional and that he didn't incorporate an additional elelment of freedom in his left arm motion to allow for pronation/supination (release of PA#3) - because Nesbit openly admitted to that fact in the discussion that ensued at BM's AntiSummit II.
Jeff.
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Post by tomdavis76 on Jun 4, 2012 23:01:27 GMT -5
Tom/Jeffy wrote-: "Easy, you don't cup it. Hogan said the cupping was deliberate and only happened when he consciously did it." I disagree. Hogan always had a cupped left wrist at his end-backswing due to having an intact LAFW/GFLW at the end-backswing position. He may at times have cupped the left wrist more by increasing the degree of left wrist dorsiflexion, but then the clubface would not be parallel to the back of his lower left forearm and it would be more open. Tom/Jeffy has not shown any visual evidence that Hogan actually did that in his swing action - even though Hogan claimed to use that "secret" to avoid hooking the ball. I believe that Hogan's cupping was simply due to the adoption of a weak left hand grip, which automatically produces cupping at the end-backswing position when the LAFW is intact. Well, Hogan showed everyone the difference between his "non-cupped" and "cupped" left wrist in the Life magazine article. I consider this more than adequate "visual evidence": Easy to see here (other than for Jeff Mann, of course) that, with the "secret", the clubface is NOT parallel to the left forearm, and is more "open", just as Hogan said it was. Only Jeff Mann would have this definitive evidence in front of him, then deny it exists.
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Post by imperfectgolfer on Jun 5, 2012 8:34:54 GMT -5
Tom-Jeffy wrote-: "Easy to see here (other than for Jeff Mann, of course) that, with the "secret", the clubface is NOT parallel to the left forearm, and is more "open", just as Hogan said it was. Only Jeff Mann would have this definitive evidence in front of him, then deny it exists." Jeffy is correct to state that if Hogan was really dorsiflexing his left wrist to a degree that is more than is biomechanically due to a GFLW, then the clubface would not be parallel to the back of the lower forearm and it would be more open. I am not disputing that Hogan did this on a selective basis - I have only stated that I have never seen it in a capture image from a "real life" swing. In all the images that I have seen involving his "real life" swing, he has his clubface parallel to the back of his lower left forearm - which is compatible with a GFLW and intact LAFW. Jeffy calls that posed photo "definitive evidence". That is not definitive evidence because it doesn't represent a "real life" full swing. I have been aware of Hogan's secret for years - because it was well described in David Leadbetter's book "The Fundamentals of Hogan" which I have quoted in my website's review papers on a number of occasions over the past 5 years. On page 56 of the book, Hogan demonstrates his "secret" in a posed photo and one can clearly see that the toe of the club is pointing straight down towards the ground. Note that in diagram 2, he has a slightly cupped left wrist (GFLW) and an intact LAFW. Note that his finger knuckles are perpendicular to the long axis of his left forearm. In the first posed image, he is dorsiflexing his left wrist more and you can see the change in the alignment of his finger knuckles, which have become more horizontal to the ground. That altered alignment would also cause the palm of his right hand to move over-the-top and become vertically oriented (as can be seen in the Life magazine photo). Here is Jeffy's animated gifs where he claims that Hogan is performing a fade swing and draw swing. i223.photobucket.com/albums/dd102/jeffy10028/FadevDraw.gif [/img] Although the image is blurred and sub-optimal, I cannot see any difference in his degree of cupping in those two comparison animated gifs, or any change in his right palmar alignment at the end-backswing position. Jeffy has not still not explained why he believes that a varying degree of left forearm pronation is biomechanically involved in this "secret move". I am also curious to see anybody explain why a slightly greater degree of cuppping (ala Hogan' secret) will result in a fade ball flight. Under normal circumstances, that "extra degree" of cupping will disappear by P6 unless one deliberately holds onto that "extra degree" of left wrist dorsiflexion. Then, it would require precision timing to convert to an AFLW/arched left wrist by impact with great consistency. Jeff.
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Post by Guest on Jun 5, 2012 13:53:38 GMT -5
I am curious Jeff, how do you know that tomdavis76 is Jeffy? I mean, Jeffy claims he is all knowing about the golf swing and an expert on Hogan's swing for years and he has definitely belittled anyone who hides behind screen names. You're telling us now that he is doing the same thing he abhors?
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Post by imperfectgolfer on Jun 5, 2012 14:37:01 GMT -5
Guest,
It doesn't take long to know when Jeffy is hiding behind false names because of his writing style and pattern of argument/pattern of insults. This is now the 3rd time that he has done this - after he was initially banned under his regular "jeffy" name. He will get banned again if he starts to use 'ad hominem' insults in his posts. I don't at all mind if he disagrees with my point-of-view and if he posts contrary opinions re: golf swing mechanics/biomechanics, but there is an ongoing policy of ZERO tolerance re: unnecessary 'ad hominem' insults in this golf forum.
Jeff.
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Post by tomdavis76 on Jun 5, 2012 22:46:17 GMT -5
Tom-Jeffy wrote-: "Easy to see here (other than for Jeff Mann, of course) that, with the "secret", the clubface is NOT parallel to the left forearm, and is more "open", just as Hogan said it was. Only Jeff Mann would have this definitive evidence in front of him, then deny it exists." Jeffy is correct to state that if Hogan was really dorsiflexing his left wrist to a degree that is more than is biomechanically due to a GFLW, then the clubface would not be parallel to the back of the lower forearm and it would be more open. I am not disputing that Hogan did this on a selective basis - I have only stated that I have never seen it in a capture image from a "real life" swing. In all the images that I have seen involving his "real life" swing, he has his clubface parallel to the back of his lower left forearm - which is compatible with a GFLW and intact LAFW. [/b][/quote] The clubface is not parallel to the left forearm here, from the Life cover, which s a "real life" swing: Another from the same shoot: An interesting comparison of a 1947 pre-"secret" driver swing to a 1948 post-"secret" swing: considerably more toe down post-"secret". Same thing 1947 v. 1954: Another "toe down" swing from 1953: A pre-"secret" top of the swing with the clubface parallel to the left forearm: In the 1964 Shell match, Hogan hit a lot of draws. Not much cup evident here in these two swings: [/b][/quote] Then why did you claim no knowledge of a "secret" a few days ago? Remember the post below??? Tom, I believe that there are no secrets in Hogan's swing, and I think that it's BS to talk of pre-secret and post-secret. Jeff. [/img][/quote] It is hardly a "claim": it is obvious that the shot on the left is a draw and the one on the right is a fade. Look at where Hogan's head turns post-impact. Do you think Hogan looked left on fades and to the right on draws?? Obviously blurry, but it can't be ruled out that there is NOT more cup on the right. That should be obvious, especially in light of your infatuation with an intact "left arm flying wedge". Dorsiflexion of the left wrist by itself would shift the clubhead toward the target line at the top, causing the shaft to "cross the line". Pronating the left forearm, which will "lay off the club" as well as open the clubface, is needed to maintain an intact LAFW. [/b]. Under normal circumstances, that "extra degree" of cupping will disappear by P6 unless one deliberately holds onto that "extra degree" of left wrist dorsiflexion. Then, it would require precision timing to convert to an AFLW/arched left wrist by impact with great consistency. Jeff.[/quote] Obviously, it isn't just the cupping. That's either ignorance or lying. The pronation required to keep the LAFW intact opens the face, as does the right shoulder external rotation we see by Hogan as the backswing ends, as evidenced by the right elbow movement down and towards the ball. Is it really so hard? With the "secret", the face is opened beyond the "normal" amount, and remains open at impact. Without the "secret", the face is less open at the top as well as at impact, and the ball draws. Does Jeff Mann have a better explanation?
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Post by imperfectgolfer on Jun 6, 2012 9:33:31 GMT -5
Jeffy has posted a number of photos showing that Hogan cupped his left wrist more post-secret. I find some of the images less convincing - for example the following image. I think that he has a GFLW (with minimal cupping) and an intact LAFW. Note that the knuckles of his left hand are not as vertically-oriented as they are in the 2nd image of the next Hogan photo comparison. However, I would agree that the following comparison shows a significant difference. I would readily agree that Hogan's left wrist is more cupped in image 2 and that the toe of the club is pointing more downwards - even though the watchface area on the back of Hogan's left lower forearm hasn't rotated more due to a greater degree of left forearm pronation. Consider Jeffy's explanation of the underlying biomechanics. Jeffy stated-: "Dorsiflexion of the left wrist by itself would shift the clubhead toward the target line at the top, causing the shaft to "cross the line". Pronating the left forearm, which will "lay off the club" as well as open the clubface, is needed to maintain an intact LAFW." I disagree! Dorsiflexion of the left wrist would only shift the clubhead across the line if the right hand allowed that movement to occur. In the posed/Life photographs, Hogan doesn't allow that to happen by employing the equivalent of a twistway maneuver to keep the clubshaft from changing its angulation. He is presumably applying a counterclockwise torque with his left and right hand that makes the left palm and right palm become more vertical. These are wrist/finger torquing motions and not forearm motions. Pronating the left forearm will not open the face to the clubhead arc. It will change the clubhead arc by altering the clubshaft angle and any "apparent" opening of the clubface relative to the horizon is due to the changing clubshaft angle, and not due to a wrist torquing motion that changes the clubface orientation relative to the clubhead arc. Jeffy wrote-: "Is it really so hard? With the "secret", the face is opened beyond the "normal" amount, and remains open at impact. Without the "secret", the face is less open at the top as well as at impact, and the ball draws." That Jeffy argues in that simplistic manner doesn't surprise me. First of all, if the face is slightly less open at impact, a fade shot should turn into a straight shot and not necessarily a draw. For the clubface to be more open at impact means that one-of-two possibilities exist - i) Hogan's left forearm doesn't rotate back to neutral by impact or ii) he has more forward shaft lean at impact due to a greater amount of left wrist arching. I cannot easily understand how those biomechanical phenomena have anything to do with the degree of opening of the clubface at the end-backswing position due to the use of a wrist torquing action at the end-backswing position. 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. Jeff.
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Post by imperfectgolfer on Jun 6, 2012 10:15:50 GMT -5
One of the advantages of debating golf swing biomechanics/mechanics online is that it allows me to gain new insights and revise my thinking. I have been thinking more about the biomechanics of Hogan's "secret move". Consider this photo comparison. In image 1, Hogan's clubface is more open and the toe of the club is pointing more downwards - but there is no change in the angulation of the club and the degree of forearm pronation. So, what makes it biomechanically possible? I have previously argued that Tapio's torquing maneuver where the clubface became closed (rather than open) during his video-demonstrated left palmar flexion action was due to the superimposition of a forearm rotary element on a "pure" left palmar flexion motion (which should only change the clubshaft angle without torquing the club about its longitudinal axis). I now believe that I was wrong. I now believe that it is due to a finger torquing action. What Tapio does in his video-demonstrated left palmar flexion action is that he torques the grip end of the club with his fingers by gripping the club more firmly while he palmar flexes the left wrist. I think that Hogan is doing the opposite in his described "secret move". In image 1, note that there is greater "gap" between the grip end of the club and the lower palm (thenar area). I now think that when Hogan dorsiflexes his left wrist more at the end-backswing position, that he is gripping the club less firmly against his lower palm and that allows the clubface to open without there being any change in the clubshaft angulation angle. This explanation also explains why I could never previously identify any difference by looking at capture video images of Hogan's swing. One cannot discern any "difference" in finger torquing strength by simply looking at arm/forearm/wrist motions. Jeff.
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Post by golfpro on Jun 6, 2012 15:35:27 GMT -5
Dorsiflexion of the left wrist by itself would shift the clubhead toward the target line at the top, causing the shaft to "cross the line". Pronating the left forearm, which will "lay off the club" as well as open the clubface, is needed to maintain an intact LAFW. Tom, this is not exactly true IMO. You said it yourself, pronating the left forearm will lay off the club and in a good golf swing the more you cup the left wrist on the backswing the more the left forearm tends to pronate. It would take a very awkward move to cup the wrist and supinate the left forearm on the backswing. You would have to drag the handle a lot in the takeaway and get the club really steep with the right arm & elbow getting high and behind you to do it. It's right arm and hand positioning that mostly contributes to the club getting across the line at the top. Right arm ER, with right forearm pronation & a lack of right wrist flexion will get the shaft across the line.
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Post by tomdavis76 on Jun 6, 2012 20:25:49 GMT -5
Dorsiflexion of the left wrist by itself would shift the clubhead toward the target line at the top, causing the shaft to "cross the line". Pronating the left forearm, which will "lay off the club" as well as open the clubface, is needed to maintain an intact LAFW. Tom, this is not exactly true IMO. You said it yourself, pronating the left forearm will lay off the club and in a good golf swing the more you cup the left wrist on the backswing the more the left forearm tends to pronate. Sorry, I'm not following; what "is not exactly true"? What brings this up? I never mentioned supination in the backswing, although that's how Miller Barber took it back (or maybe he just never internally rotated the left shoulder) while maintaining the cup in his left wrist that was established at address. I'm adopting a similar backswing, BTW. I assume you mean right shoulder IR and lack of right wrist extension, or dorsiflexion (which is functionally no different than extending or dorsiflexing the left wrist). Right shoulder ER and right wrist dorsiflexion would both act to lay off the shaft.
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Post by tomdavis76 on Jun 6, 2012 21:04:45 GMT -5
Consider Jeffy's explanation of the underlying biomechanics. Jeffy stated-: "Dorsiflexion of the left wrist by itself would shift the clubhead toward the target line at the top, causing the shaft to "cross the line". Pronating the left forearm, which will "lay off the club" as well as open the clubface, is needed to maintain an intact LAFW." I disagree! Dorsiflexion of the left wrist would only shift the clubhead across the line if the right hand allowed that movement to occur. In the posed/Life photographs, Hogan doesn't allow that to happen by employing the equivalent of a twistway maneuver to keep the clubshaft from changing its angulation. 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! It is easily seen that, with the "secret", Hogan's right wrist is moving toward palmar flexion, the opposite of a "twistaway", and not remaining bent or cupped. BTW, where is the right hand twistaway maneuver in the photo on the left below???: Of course, Hogan plainly states in the Life article that left forearm pronation accompanies the cupping. But why would anyone pay attention to what Hogan said happened?I have no idea what you are talking about here: the wrist is a joint that either palmar flexes (arches) or dorsiflexes (cups). What the hell are "wrist/finger torquing motions" Of course it will: pronation and supination only influence the z-axis. Uh, no. That is completely wrong. How would pronation/supination, that only influence the z-axis, have an effect on the x-axis, which is what controls the clubshaft angle? And that you argue convoluted make-believe doesn't surprise me either!!! BTW, have you ever heard of Occam's Razor??? Your argument is with Hogan: he said that if he did not use the "secret", he hit a draw. But, of course, what Hogan wrote has no standing with you. Well, you have a lot to learn, then! Both the end-of-backswing left forearm pronation that accompanied the cupping and the strong right shoulder external rotation (which rotates both upper arms clockwise) at the end of the backswing open the clubface. Ah, sounds like early supination to me!!!
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Post by golfpro on Jun 6, 2012 22:07:44 GMT -5
Sorry, I'm not following; what "is not exactly true"? That cupping the left wrist by itself will shift the clubhead towards the target line causing the shaft to cross the line. Correct, I meant to say "lack of right wrist extension."
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Post by tomdavis76 on Jun 6, 2012 23:14:45 GMT -5
Sorry, I'm not following; what "is not exactly true"? That cupping the left wrist by itself will shift the clubhead towards the target line causing the shaft to cross the line. Why not? It has to.
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Post by imperfectgolfer on Jun 7, 2012 0:13:54 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. Jeffy wrote-: "Of course, Hogan plainly states in the Life article that left forearm pronation accompanies the cupping. But why would anyone pay attention to what Hogan said happened? " The answer is simple. There is no difference in the degree of rotation of the left forearm in those two photos and one can clearly discern that one doesn't have to pronate one's left forearm when performing the twistaway action that I described above. Jeffy wrote-: "Uh, no. That is completely wrong. How would pronation/supination, that only influence the z-axis, have an effect on the x-axis, which is what controls the clubshaft angle?" Look at this BM description of rotation about the different axis'. I think that Jeffy is wrong. Pronation and supination of the left forearm (when the clubshaft is lying on the inclined plane) will cause a rotational movement of the clubshaft relative to the beta axis (X axis) with a significant angular motion of the clubshaft. Any rotation about the Z axis in that BM-diagram occurs to a twisting motion of the clubshaft around its longitudinal axis, and where there is significant clubface rotation but no clubshaft angular motion - and it doesn't involve any left forearm rotary motion. Jeffy wrote-: "Well, you have a lot to learn, then! Both the end-of-backswing left forearm pronation that accompanied the cupping and the strong right shoulder external rotation (which rotates both upper arms clockwise) at the end of the backswing open the clubface." It is easy for an independent forum member to see that Jeffy is wrong. Simply adopt a neutral left hand grip and get to an end-backswing position using only your left upper limb and making sure that you have an intact LAFW at the end-backswing position - then simply pronate your left forearm slightly more at that time point. That extra left forearm pronatory motion should rotate the entire LAFW as an unit and the clubshaft angle should become more horizontal (relative to the ground) but the clubface should still remain parallel to the back of the lower left forearm. Jeff.
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Post by golfpro on Jun 7, 2012 1:21:07 GMT -5
That cupping the left wrist by itself will shift the clubhead towards the target line causing the shaft to cross the line. Why not? It has to. Tom, because it doesn't that's why. Why does it have to?
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