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Post by imperfectgolfer on Dec 29, 2013 22:19:48 GMT -5
Jeffy, You posted this image You then stated-: " There are a lot of other things going on between address and the impact zone, but this comparison should be illuminating. Below, by comparing the first frame to the second, we can see how PF opens the clubface relative to the target line, as well as moves the clubhead behind the hands on an arc. In the third frame, we can see how the clubface stays square to the path as it travels along the arc from the second frame, and is square to both the arc and the target line at impact.I agree that there is lot of things going on between P1 and P6.5, and that's why I don't think that it is valid to compare images from P6.5 to P1 to make a point. You claim that the clubface is open in image 2 due to PF. However, I think that it is open because the left forearm is still in the process of completing its counterclockwise rotation (that constitutes the PA#3 release action) - note how the left forearm is still significantly pronated in image 2. I also don't think that the clubhead is well behind the hands due to PF. I think that it is due to the fact that the PA#2 release action (club releasing phenomenon) is still incomplete and that the clubhead has not yet caught up to the hands. I also don't know why you believe that the clubface is square to the path between image 2 and image 3. I think that the PA#3 release action still has to be completed between image 2 and image 3 - note how much more the FLW is rotated counterclockwise in image 3 compared to image 2. In providing an explanation, I think that you should only refer to what is happening between P6.5 and P7. I think that you confuse things by comparing P6.5 images to images at P1 or P5.5/6 because there are many biomechanical elements that have changed in that interim time period. I am particularly interested in knowing why you don't believe that left wrist bending will close the clubface to the CH arc. If you believe that changes in the plane of the clubshaft due to left wrist bending affects the degree of clubface closure, then please explain precisely how it affects it - while only referring to what is happening between P6.5 and P7. Thanks, Jeff.
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Post by imperfectgolfer on Dec 30, 2013 0:18:53 GMT -5
In this post, I am going to explain why I believe that left wrist bending closes the clubface while left wrist bowing opens the clubface if it happens between P6.5 and P7. The explanation is complex and one needs to understand how Homer Kelley's TGM machine works. Here is a diagram showing the TGM model. Note that it consists of a single arm lever that moves along the surface of the inclined plane. It is shaped like an ice hockey stick at the end, and that offset section represents the clubhead. Note that there are two hinges at the top. The one hinge can be arranged to move the single arm lever along the surface of the inclined plane in an arced manner, and it can also be arranged to allow the lever to rotate while it is moving along that arc if the hinge is set in the dual-horizontal arrangement. The second hinge adjusts the angle of the lever so that it can be kept flush to the surface of the inclined plane. Now, watch this you-tube video to understand how it all works. You only need to understand how the hinges work, and how it functions when set to the dual-horizontal hinge arrangement that allows the lever to rotate about its longitudinal axis (gamma rotation) while it is moving in an angular manner along the surface of the inclined plane. Here is an image showing how the lever moves along the surface of the inclined plane. The red curved arrow represents the angular motion of the lever that can create a CH path. It is important to understand that the lever is continuously rotating counterclockwise between P6 and P7 - similar to the rotation of Kellie Oride's left arm/forearm and clubshaft in my previous post. Now, I am going to introduce a personal modification of that TGM model (where the single lever represents both the left arm and the clubshaft) by creating a hinge joint in the middle of the lever that will represent the left wrist joint. The red dot in the middle of the lever is the point where I insert a very sophisticated servomotor-controlled hinge - hinge C. That hinge C joint breaks the single TGM lever into two levers - central lever (representing the left arm) and peripheral lever (representing the clubshaft). Hinge C is designed to only allow the hinge joint to bend in a horizontal fashion (representing left wrist bending and left wrist bowing). Now imagine the lever moving along the surface of the inclined plane board with hinge C being able to vary the degree of bend at hinge C in a perfectly controllable manner to i) controllable varying degrees of magnitude and at ii) controllable varying rates between P6 and P7. In other words, imagine a highly sophisticated computer that can control hinge C so that one can vary the degree of bend (in a bowing or bending manner) at hinge C at all time points between P6 and P7 to an amazing degree of exactitude. Now, if hinge C bends (= left wrist bends) it could move the peripheral lever below hinge C (which represents the clubshaft) off-plane. So, imagine that I insert a very sophisticated servomotor-controlled hinge at hinge B that can instantaneously correct for any off-plane motions due to bending (or bowing) at hinge C - thereby keeping the clubshaft always on-plane between P6 and P6. That eliminates the effect of off-plane clubshaft motions due to left wrist bending/bowing. ( Addendum added later: I could also change the functioning of hinge C so that it is capable of also moving in a radial-ulnar direction that is perpendicular to the surface of the inclined plane board so that is can assist in always keeping the clubshaft on-plane whenever the left wrist bends-or-bows). Now, let's consider what happens when the left wrist bends (or bows) between P6 and P7. Scenario 1 represents the situation where the left wrist remains constantly flat between P6 and P7 - similar to Kellie Oride's swing action between P6 and P7. The clubface will then rotate from open to square between P6 and P7 as shown in the next diagram. Now imagine, that we controllably cause hinge C (= left wrist) to bend to a perfectly-controllable degree between P6 and P7 - scenario 2 of this next diagram. Note that any bending action of hinge C causes the clubshaft to move slightly forward relative to the left arm (and that is equivalent to a left wrist flipping action) and that will close the clubface more than the FLW scenario. Scenario 3 shows the effect of left wrist bowing - and it causes the clubshaft to be slightly back (away from the target) relative to the left arm and that will cause opening of the clubface. Now, you may ask what biomechanical actions represent the computer-controlled action of hinge B that allows the clubshaft to remain on-plane during a left wrist bending/bowing motion between P6.5 and P7. The answer is the combination of i) the degree of left arm angulation outwards away from the torso and ii) the ability of the left wrist joint to either radially-or-ulnarly deviate and thereby vary the accumulator #3 angle, and that combination allows a golfer to keep his clubshaft on-plane during any left wrist bending-or-bowing action that happens between P6.5 and P7. In other words, a real life" skilled golfer subconsciously varies those elements of his downswing action if he has acquired the skill to keep the clubshaft on-plane between P6 and P7. My "hinge C and hinge B computer-controlled arrangement" explanation eliminates off-plane motions of the clubshaft due to left wrist bending/bowing actions that may happen between P6 and P7, and it shows the "pure" effect of left wrist bending/bowing on the rate of clubface closure between P6 and P7. I think that it shows that any left wrist bending action between P6.5 and P7 must increase the rate of clubface closure that is naturally happening due to a PA#3 release action (= clubface closing effect) while any left wrist bowing action between P6.5 and P7 must decrease the the rate of clubface closure that is naturally happening due to a PA#3 release action (= clubface opening effect). Jeff.
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Post by tomdavis76 on Dec 30, 2013 0:52:39 GMT -5
Guess I have to dumb it down even more. Address a ball with a club, with the hands in front of the center of the body and the shaft vertical with a slight bend in the left wrist. Palmar flex the left wrist while keeping the hands in the same position relative to the body. The clubhead will swing back on an arc inside of the target line, the clubface will open relative to the target line and the clubface will stay square to the arc the clubhead traveled on.
To confirm that the clubface has stayed square to the arc, rotate your body counter-clockwise, without moving any other body part, until the clubhead is back to the ball. The hands will be further away from the target line and forward from where they were at address, and the clubface will be delofted and square to the target line.
Now, let's see how bending the left wrist does not close the face relative to the path. Again, address a ball as described above. Rotate the body clockwise until the clubhead is two or three feet from the ball, while keeping the hands in the same position relative to the body. Bend the left wrist, then rotate the body clockwise until the clubhead is back to the ball. The hands will be behind the ball and further away from the target line than they were at address, and the clubface will be more lofted and square to the target line.
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Post by imperfectgolfer on Dec 30, 2013 1:30:09 GMT -5
Jeffy,
You wrote-: "Guess I have to dumb it down even more. Address a ball with a club, with the hands in front of the center of the body and the shaft vertical with a slight bend in the left wrist. Palmar flex the left wrist while keeping the hands in the same position relative to the body. The clubhead will swing back on an arc inside of the target line, the clubface will open relative to the target line and the clubface will stay square to the arc the clubhead traveled on.
To confirm that the clubface has stayed square to the arc, rotate your body counter-clockwise, without moving any other body part, until the clubhead is back to the ball. The hands will be further away from the target line and forward from where they were at address, and the clubface will be delofted and square to the target line.
I have no problem understanding your explanation - particularly the bold-highlighted parts. The clubface will remain square to the CH arc in your described scenario because you have kept the left hand stationary from a rotational perspective. However, that's my point - your described scenario is "artificial" and not relevant to a "real life" golf swing where the hands are continuously rotating counterclockwise between P6.5 and P7 thereby continuously rotating the clubface counterclockwise as the clubhead moves along the CH arc. Therefore, in a "real life" golf swing any clubface-opening effect due to left wrist bowing is superimposed on a continuously closing clubface and it only modulates its rate of closing - decreasing the rate of closing, which means that left wrist bowing has a clubface-opening influence.
The same phenomenon applies to the effect of left wrist bending - but in reverse. Left wrist bending increases the rate of clubface closing that is happening continuously due to the release of PA#3. In your described model, you only have two motions - body motions and left wrist hinging motions in a horizontal plane - and you have ignored the counterclockwise rotational motions of the left forearm that is happening naturally between P6.5-P7.
Jeff.
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Post by tomdavis76 on Dec 30, 2013 1:58:36 GMT -5
Jeffy, You wrote-: " Guess I have to dumb it down even more. Address a ball with a club, with the hands in front of the center of the body and the shaft vertical with a slight bend in the left wrist. Palmar flex the left wrist while keeping the hands in the same position relative to the body. The clubhead will swing back on an arc inside of the target line, the clubface will open relative to the target line and the clubface will stay square to the arc the clubhead traveled on.
To confirm that the clubface has stayed square to the arc, rotate your body counter-clockwise, without moving any other body part, until the clubhead is back to the ball. The hands will be further away from the target line and forward from where they were at address, and the clubface will be delofted and square to the target line.I have no problem understanding your explanation - particularly the bold-highlighted parts. The clubface will remain square to the CH arc in your described scenario because you have kept the left hand stationary from a rotational perspective. However, that's my point - your described scenario is "artificial" and not relevant to a "real life" golf swing where the hands are continuously rotating counterclockwise between P6.5 and P7 thereby continuously rotating the clubface counterclockwise as the clubhead moves along the CH arc. Therefore, in a "real life" golf swing any clubface-opening effect due to left wrist bowing is superimposed on a continuously closing clubface and it only modulates its rate of closing - decreasing the rate of closing, which means that left wrist bowing has a clubface-opening influence.[/size] The same phenomenon applies to the effect of left wrist bending - but in reverse. Left wrist bending increases the rate of clubface closing that is happening continuously due to the release of PA#3. In your described model, you only have two motions - body motions and left wrist hinging motions in a horizontal plane - and you have ignored the counterclockwise rotational motions of the left forearm that is happening naturally between P6.5-P7. Jeff.[/quote] Utter nonsense. If the club has zero rotation around the shaft, or is rotating at 10,000 degrees per second, palmar flexion or extension will not change the rate of rotation. It can't because flexion or extension exerts no rotational torque along the shaft. As we have discussed before, if the left wrist is palmar flexing through impact, that will send the path to the right. If a player wants to play a draw and has a slightly closed face to the path, this path shift will start the ball to the right and the ball will draw back to the target line. That's why drawers palmar flex through impact. Similarly, with a player that wants to hit a fade, extending through impact will send the path to the left and start the ball to the left of the target line. If the face is open to the path, the ball will drift back towards the target. That's why faders extend through impact. If palmar flexion opened the face, players that palmar flexed would be slicers and hookers would use palmar flexion to cure a hook. Obviously, neither is the case.
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Post by imperfectgolfer on Dec 30, 2013 11:33:07 GMT -5
Jeffy, You wrote-: " Utter nonsense. If the club has zero rotation around the shaft, or is rotating at 10,000 degrees per second, palmar flexion or extension will not change the rate of rotation. It can't because flexion or extension exerts no rotational torque along the shaft." Who stated that palmar flexion/extension affects the rate of rotation of the shaft around its longitudinal axis? I didn't. I simply stated that it affected the rate of closing of the clubface that is due to a PA#3 release action. A PA#3 release action (due to left forearm supination) doesn't rotate the clubshaft about its longitudinal axis and it happens over a clubhead travel distance of 18-24". Consider AL's PA#3 action. Look at how little the clubface is closing (relative to the CH arc) between image 2 and image 3 and it is roughly proportional to the amount the left forearm/GFLW is rotating in those images. In other words, the clubface's counterclockwise rotation occurs incrementally over a distance of 18-24" between P6.5 and P7. Left wrist flexion/extension (which often also occurs over a CH travel distance of 18-24") only affects the degree of rotation by minutely changing the clubface orientation angle by moving the clubshaft minutely forward (or backward) of its position - compared to a situation where a golfer maintains a stable FLW (like Kellie Oride). If the clubface is moved slightly forward (due to left wrist extension) then it is increasing the degree of closing that would otherwise have existed at that time point due to a PA#3 release action - because the clubface closes to the arc when the left wrist extends. It is not due to any direct alteration of the clubface rotation, that is biomechanically due to counterclockwise rotation of the left forearm. You also wrote-: " As we have discussed before, if the left wrist is palmar flexing through impact, that will send the path to the right. If a player wants to play a draw and has a slightly closed face to the path, this path shift will start the ball to the right and the ball will draw back to the target line. That's why drawers palmar flex through impact." I definitely don't agree with that assertion. I don't believe that left wrist palmar flexion sends the CH path to the right because any palmar flexion occurs over a very long distance of CH travel between P6.5 -P7, or much longer if the golfer has a palmar flexed left wrist at P4 (like Dustin Johnson). I think that the "fact" that Dustin Johnson has a palme flexed left wrist doesn't alter his CH path at all and I believe that golfers who want to be push-drawers deliberately generate an in-to-out CH path through impact by other biomechanical actions. I think that only gross hackers would try to palmar flex their left wrist over a few inches of hand travel through impact, and that would cause both the CH path and clubface orientation angle to be directed rightwards. The same applies to left wrist extension. You wrote-: " Similarly, with a player that wants to hit a fade, extending through impact will send the path to the left and start the ball to the left of the target line. If the face is open to the path, the ball will drift back towards the target. That's why faders extend through impact." I believe that's science fiction. I have never seen a skilled golfer extend his left wrist through impact in order to hit a fade. If he actually extended his left wrist through impact, the clubface would be closed and not open to the ball-target line (because as you previously stated in reply #107 the clubface remains square to any altered path with any intervening left wrist extension action). How would a golfer get the face to be open to the path when left wrist flip-bending through impact? Jeff.
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Post by tomdavis76 on Dec 30, 2013 12:09:00 GMT -5
Jeffy, You wrote-: " Utter nonsense. If the club has zero rotation around the shaft, or is rotating at 10,000 degrees per second, palmar flexion or extension will not change the rate of rotation. It can't because flexion or extension exerts no rotational torque along the shaft." Who stated that palmar flexion/extension affects the rate of rotation of the shaft around its longitudinal axis? I didn't. I simply stated that it affected the rate of closing of the clubface that is due to a PA#3 release action. A PA#3 release action (due to left forearm supination) doesn't rotate the clubshaft about its longitudinal axis and it happens over a clubhead travel distance of 18-24".[/size][/quote] Of course forearm rotation, as well as humeris rotation, rotates the club around its longitudinal axis: that's how the clubface is opened and closed in a golf swing. As I said earlier, you are hopelessly ignorant of what influences the clubhead relative to the path. [/size][/quote] That opening and closing is relative to the target line, by changes in the path, not by changes in the clubface orientation relative to the path. [/size] I think that only gross hackers would try to palmar flex their left wrist over a few inches of hand travel through impact, and that would cause both the CH path and clubface orientation angle to be directed rightwards.[/quote] You need to think about it some more. It is easy to demonstrate that palmar flexing at address, while keeping the hands stationary, will move the club inside relative to the target line, creating an in-to-out path to the ball. As palmar flexion is increased, the path will become even more in-to-out, or more oriented towards the right of the target. Just look at Aiko below: her path is far more in-to-out at P6, when the left wrist is palmar flexed, than at P2, when the left wrist is bent: [/size] That's why faders extend through impact.[/i]" I believe that's science fiction. I have never seen a skilled golfer extend his left wrist through impact in order to hit a fade. If he actually extended his left wrist through impact, the clubface would be closed and not open to the ball-target line (because as you previously stated in reply #107 the clubface remains square to any altered path with any intervening left wrist extension action). How would a golfer get the face to be open to the path when left wrist flip-bending through impact?[/size][/quote] Any number of ways. I did not say that bending the left wrist would open the face to the path; I said "if the face is open to the path".
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Post by tomdavis76 on Dec 30, 2013 12:26:04 GMT -5
BTW, any golfer that "releases" palmar flexion through impact, allowing the left wrist to become less bowed, is extending through impact and countless golfers do that without hooking.
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Post by imperfectgolfer on Dec 30, 2013 12:57:37 GMT -5
Jeffy,
You wrote-: "That opening and closing is relative to the target line, by changes in the path, not by changes in the clubface orientation relative to the path."
I disagree!
I believe that AL's uses a PA#3 release action which means that the clubface must be closing relative to the CH arc and not only the ball-target line.
You wrote-: "Youneed to think about it some more. It is easy to demonstrate that palmar flexing at address, while keeping the hands stationary, will move the club inside relative to the target line, creating an in-to-out path to the ball. As palmar flexion is increased, the path will become even more in-to-out, or more oriented towards the right of the target. "
I disagree that it will happen in that described manner in a golf swing because your described scenario is artificial and you are keeping the hands stationary, which means that the CH arc is produced solely by the left wrist palm flexor maneuver. I believe that palmar flexion that happens during a golf swing does not necessarily alter the path, especially if it is produced when the clubshaft is not in motion (eg. at P4) or if palmar flexion happens during the backswing action. If it happens during the backswing (as occurs in Dustin Johnson's swing), it cannot possibly be directly responsible for creating an in-to-out CH path.
By the way, I don't see that the path is more in-to-out in ALs' P6 image compared to her P2 image - I can only see that the clubshaft is angled more back at the P6 location. That angled-back position is simply due to the fact that comes down from P4 to P6 with her clubshaft underplane, but having an underplane clubshaft position at P6 doesn't mean that the CH path at the moment of impact is going to be in-to-out.
You also wrote-: "Any number of ways. I did not say that bending the left wrist would open the face to the path; I said "if the face is open to the path".
Please describe all those ways which explains how the clubface could be maintained open through impact if a golfer flip-bends the left wrist through impact.
Jeff.
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Post by tomdavis76 on Dec 30, 2013 13:21:16 GMT -5
Jeffy, You wrote-: " That opening and closing is relative to the target line, by changes in the path, not by changes in the clubface orientation relative to the path." I disagree! I believe that AL's uses a PA#3 release action which means that the clubface must be closing relative to the CH arc and not only the ball-target line.[/size][/quote] That goes without saying: at P6 her clubface is about ten degrees open to the path and she'll need close the clubface through counter-clockwise rotation of either the forearms or humeris. [/size][/quote] Of course not: if at impact the clubhead is at the apex of its arc, the path will be straight at that instant. But, prior to that point, the path will be more in-to-out with a palmar flexed left wrist than a bent one. It's obvious from the pictures of Aiko. [/size] Jeff.[/quote] There is just one way that describes why the clubface doesn't close relative to the arc when the left wrist bend: it doesn', because flexing and bending does not apply any rotational force or torque along the shaftt. Opening and closing the clubface to the arc is controlled by the grip and the rotation of the humeris and forearm, not by bending or flexing the wrist.
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Post by imperfectgolfer on Dec 30, 2013 13:31:53 GMT -5
Jeffy,
I think that we have not reached any agreement on this topic, but we have certainly had an opportunity to express our contrary opinions, so I think that it would be reasonable to agree-to-disagree at this point, and move to the next topic in my long list.
Jeff.
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Post by imperfectgolfer on Jan 9, 2014 12:22:55 GMT -5
I am going to re-address some comments made by jeffy in order to clarify my position on this topic of clubface opening/closing due to left wrist bowing/bending. Jeffy wrote-: " Everyone knows that flattening the left wrist or PFing at the top of the swing "shuts" the face relative to the forearm (you posted as much earlier in the thread), although in reality the face is simply delofting and the clubhead shifted to a flatter plane. Why would it be any different at any other point in the swing, including the takeaway?" Consider the bold-highlighted statement where Jeffy claims that the clubface is simply delofting when a golfer bows his left wrist at the P4 position. That's obviously not true - because "pure" delofting only occurs when the movement of the clubface only happens within the plane of the clubhead arc (like a ferris-wheel) - and that will happen if the clubshaft is perpendicular to the CH arc (VSP is 90 degrees) and the clubface is moving parallel to the circumference of the CH arc. However, at P4 the clubshaft is roughly parallel to the CH arc and any bowing of the left wrist moves the clubface along an arc that is roughly perpendicular to the CH arc - see diagram below. perfectgolfswingreview.net/ClubfaceP4Diagram.jpg [/img] The blue curved path represents the CH arc. The green line represents the left arm and the red line represents the clubshaft while the violet line represents the clubface. When the clubface closes due to a left wrist bowing action, the clubface closes in the direction of the black-arrowed path - which is roughly perpendicular to the CH arc path. Delofting happens in a plane that is parallel to the circumference of the CH arc when the clubhsft is perpendicular to the CH arc (VSP is 90 degrees) and when the clubface motion is like a ferris wheel motion. Jeffy asks-: " why should it be different at any other point in the swing?" The answer is obvious! It is because the left arm and clubshaft are oriented differently at other time points in the swing relative to the CH arc. At P7, both the clubshaft and left arm are roughly perpendicular to the CH arc, the back of the left wrist is facing the target and moving roughly parallel to the CH arc. If the left wrist bows, the back of the left wrist moves away from the target and it moves the clubshaft and clubface away from the target in a plane that is roughly parallel-aligned to the circumference of the CH arc, and not in a plane that is roughly perpendicular to the CH arc as happens at P4 (black-arrowed path in the above diagram). This diagram shows the effect of left wrist bowing/bending at P7 if the ball is placed at low point - when the left arm and clubshaft are in a straight line relationship, and when the clubshaft and clubface is roughly perpendicular to the CH arc. Under those conditions, left wrist bowing will move the clubface away from its vertical (square) position to a position further back - and the clubface will be become more open (and not more closed) relative to the CH arc. Therefore, the effect of left wrist bowing on the clubface at P7 is very different to its effect at P4. I also previously made the following statement-: "T herefore, in a "real life" golf swing any clubface-opening effect due to left wrist bowing is superimposed on a continuously closing clubface and it only modulates its rate of closing - decreasing the rate of closing, which means that left wrist bowing has a clubface-opening influence." Jeffy then replied as follows-: " Utter nonsense. If the club has zero rotation around the shaft, or is rotating at 10,000 degrees per second, palmar flexion or extension will not change the rate of rotation. It can't because flexion or extension exerts no rotational torque along the shaft." It is obvious that left wrist bowing doesn't change the rate of clubface rotation (gamma rotation) due to any left forearm counterclockwise rotation that happens between P6 and P7. When I state that it modulates the rate of closing, I don't mean that it alters the degree of rotation of the clubface due to a left forearm rotary motion - and what it actually does is only fractionally change the position of the clubface by moving the clubshaft fractionally back. If the clubshaft angles back by a few degrees, thereby causing the clubhead to move back ~1cm, then the position of the clubface along the CH arc is changed by ~1cm. If the rate of closing of the clubface (due to a PA#3 release action) remains unchanged between P6 and P7, then the degree of clubface opening at the same measured time points along the CH arc between P6 and P7 is marginally changed as result of the left wrist bowing and it is changed in the direction of clubface opening, and not in the direction of clubface closing. I demonstrated that "fact" with the TGM model. The top hinge (hinge A) is vertically-oriented and it is perpendicular to the ground. However, it is not perpendicular to the inclined plane on which the clubshaft travels. It is angled relative to that inclined plane and the degree of angulation is roughly proportional to a golfer's accumulator #3 angle. When hinge A rotates clockwise in the backswing, it causes the clubshaft, and therefore clubface, to become more open relative to the inclined plane, and during the downswing the opposite effect effect is seen - the clubface is constantly closing (relative to the inclined plane) due to the counterclockwise rotation of hinge A. The rate of clubface closing is constant - because it is dependent on the "fixed" rotary motion of hinge A. At low point (nadir of the CH arc), hinge A is square to the target and therefore the clubface must be square to the target if the lever assembly (representing the combined left arm-clubshaft unit) is perfectly straight. However, if there is change in the bend of the lever assembly due to a bend in hinge C (that is functionally equivalent to left wrist bowing) then the clubface will be fractionally open at low point because the clubshaft will be fractionally angled back. The fact that the clubface is open at low point doesn't mean that left wrist bowing (bending of hinge C in a bowing direction) altered the rate of clubface closing due to the rotation of hinge A - and it only fractionally alters the position of the clubhead as it moves along the CH arc. If the clubhead moves back along the CH path then it has a clubface-opening effect (for a given degree of rotation of hinge A) and if the clubhead moves forward along the CH path then it has a clubface-closing effect (for a given degree of rotation of hinge A). Jeffy wrote-: " You need to think about it some more. It is easy to demonstrate that palmar flexing at address, while keeping the hands stationary, will move the club inside relative to the target line, creating an in-to-out path to the ball. As palmar flexion is increased, the path will become even more in-to-out, or more oriented towards the right of the target." I think that Jeffy's argument has zero merit because he is keeping the hands stationary at a ~P7 position, and simply observing what effect isolated left wrist bowing will have on the CH path and clubface angle when the hands are at that position. Left wrist bowing will obviously move the CH path inside (relative to the ball-target line) if the hands are at a P7 location. However, it will have a very different effect if the hands are located at the P4 position, and if the clubshaft is angled 90 degrees relative to the left arm - see the diagram below. Left wrist bowing will move the clubshaft somewhat downwards (groundwards) and it will cause the clubface to become more horizontal (relative to the ground) - see Dustin Johnson's P4 image below. Look at DJ at P4 - image 1. His clubshaft has moved groundwards (due to his left wrist bowing action) and his clubface has become more horizontal. Now, consider what "effect" that left wrist bowing deformity has on his clubface orientation angle at P7 - if he maintains the same degree of left wrist bowing deformity from P4 to P7. It will not affect his CH path and make it inside-out, and it will only cause his clubshaft to be more angled back at P7 if nothing else is changed in his swing action. That would produce an open clubface alignment at P7 if the degree of left forearm rotation during the downswing remained unchanged and if the degree of counterclockwise rotation of his left forearm was the same between P4 and P7 as the degree of clockwise rotation of his left forearm between P1 and P4. However, it is not exactly the same, and DJ has to fractionally increase his degree of left forearm rotation during his downswing action to counter the clubface-opening effect of having a left wrist bowing deformity at P4 and at P7 - if he wants to have a square clubface at impact. Compare DJ's address and P7 left forearm alignments. Jeff.
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Post by imperfectgolfer on Jan 9, 2014 23:17:30 GMT -5
I can imagine that many golfers will find it counter-intuitive to believe that if Dustin Johnson closes his clubface during his late backswing and has a closed clubface at P4, that he will have to rotate his left forearm more than "expected" during his downswing to obtain a square clubface by impact. However, that "fact" can be verified by carefully examining his swing videos. Here are capture views from the video. Note how his left forearm is slightly pronated at address - image 1 - due to the fact that he adopts a slightly strong left hand grip. Image 2 shows that he has significantly bowed left wrist at P6.5 that causes his clubshaft to be angled more back and that causes the clubface to appear open (and not closed). Image 3 shows him about 12" from impact - note that the clubface is still open (and not closed) to the ball-target line. Image 4 shows him at P7 with a square clubface and it required a small degree of counterclockwise rotation of the left forearm to go from image 3 to image 4. One can note that his left forearm is more rotated counterclockwise at P7 compared to P1. The same phenomenon can be seen from a front view. Here are capture images from the P1 and P7 positions. At address (image 1), the back of his left lower forearm (watchface area) is rotated clockwise (= slightly pronated) due to the fact that he adopts a slightly strong left hand grip at address. Image 2 shows him at impact - and one can see that the back of his left lower forearm faces the target, which means that it is more rotated counterclockwise. Here is another useful comparison image - showing the difference between his P1.5 and P6.5 clubface positions/orientation. Image 1 is at P1.5 - note that his clubface is slightly closed relative to the back of his left forearm - which is expected in a golfer who adopts a slightly strong heft hand grip. Image 2 is at P6.5 - note how his clubshaft is angled more backwards due his bowed left wrist. Also, note how much more the clubface is open to the ball-target line (compared to image 1). Jeff.
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