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Thread: How Biomechanists Define Movements

  1. #31
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    Quote Originally Posted by birlyshirly View Post
    Something's missing here. It could well be on my side.

    If I UD so that my ulna and radius are vertically aligned, and forearm and shaft are flat on the table top (difficult physically to do perfectly!) - then I can see flexion and extension moving the club back and forth, but the clubhead leading edge remains vertical. No axial rotation there.

    But with the wrist in RD - doesn't the same flexion and extension THEN result in axial rotation?

    Going back to my original example. With wrist in RD and clubshaft vertical - surely pronation and supination lay the clubshaft over but WITHOUT any rotation about the shaft?

    I have always worked off the understanding that the effect on the club (open/closed or lofted/delofted) depends on the combination of the 3 wrist movements we're discussing. So forearm pronation has different effects on the club depending on whether the wrist is UD or RD.

    Can you expand on why the popular definitions of open and closed face at the top of the BS are wrong? To be honest, I thought that was the point of Kelvin's video on Hogan closing the clubface through his transition.
    Sorry, I've told you pretty much all I know, which I only fully understood today after reading Kelvin's piece in the thread starter!

    As far as I know, it doesn't matter whether the wrists are in radial or ulnar deviation: flexion and extension only change the loft angle. Therefore, a cupped left wrist at the top doesn't, by itself, open the face. However, it is entirely possible that, as with Hogan, a cupped left wrist typically accompanies an extremely pronated left forearm (which, of course, opens the face). Similarly, a bowed wrist may typically accompany a less pronated left forearm (which would result in a less open face). So, the "conventional wisdom" may be a case of guilt by association.

    As far as the Hogan video on transition, the discussion centered around whether or not Hogan supinated the left forearm in transition as well as flattened the left wrist a bit.


    Jeff

  2. #32
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    Quote Originally Posted by Jeff Mann View Post
    Footwedge,

    You wrote-: "I see a rotation of the shaft in those pics of Tapio, if it was pure P.F. the shaft would lay back without rotation.

    The shaft cannot lay back because of the presence of the RFFW right palm which abuts the aft side of the grip. They prevent the club from being angularly displaced - and the club gets torqued by the fingers if he palmar flexes his left wrist when his left wrist is maximally radially deviated.

    Jeff.
    Oh, one other thing. English is the official language of "jeffy golf". No use of acronyms or a specific method's jargon unless accompanied by definitions.



    Jeff

  3. #33
    Jeff Mann Guest
    BirlyShirly wrote-:

    "If I UD so that my ulna and radius are vertically aligned, and forearm and shaft are flat on the table top (difficult physically to do perfectly!) - then I can see flexion and extension moving the club back and forth, but the clubhead leading edge remains vertical. No axial rotation there.

    But with the wrist in RD - doesn't the same flexion and extension THEN result in axial rotation?

    Going back to my original example. With wrist in RD and clubshaft vertical - surely pronation and supination lay the clubshaft over but WITHOUT any rotation about the shaft?"

    I agree with his observations.

    Jeff.

  4. #34
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    Quote Originally Posted by Jeff Mann View Post
    http://jeffygolf.com/attachment.php?...1&d=1330467081

    In this photo, Jeffy is displacing the clubshaft and disrupting his left arm flying wedge - and that is because he is allowing his right wrist to dorsiflex more. If one allows the clubshaft to become angularly displaced when palmar flexing the left wrist, then one will not end up torquing the club with one's fingers (like Tapio).

    Jeff.
    First, you used jargon and other terminology without a definition. You have been told NOT to do that.

    Second, I did NOT torque the club with my fingers and you have no way of knowing whether I did or not. You cannot make assertions like that and expect to post here.



    Jeff

  5. #35
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    Quote Originally Posted by Jeff Mann View Post
    Jeffy wrote-: "As far as I know, it doesn't matter whether the wrists are in radial or ulnar deviation: flexion and extension only change the loft angle. Therefore, a cupped left wrist at the top doesn't, by itself, open the face. However, it is entirely possible that, as with Hogan, a cupped left wrist typically accompanies an extremely pronated left forearm (which, of course, opens the face). Similarly, a bowed wrist may typically accompany a less pronated left forearm (which would result in a less open face)."

    I disagree with his conclusions. I think that the degree of left pronation that occurs in the backswing is primarily dependent on the angle of the left arm (relative to the ground) at the end-backswing position. A golfer who mimics Hogan's end-backswing left arm angle is going to need more left forearm pronation than Steve Marino who has a very steep left arm angle at his end-backswing postion.

    Presuming one gets to a particular end-backswing position with a particular left arm angle (relative to the ground) - consider what would then happen if the golfer then arches (palmar flexes) or cups (dorsiflexes) his left wrist. It will make the clubface more closed (or more open) to the clubhead arc as a result of that wrist motion.

    Jeff.
    Unsubstantiated opinion, with no evidence whatsoever. Read our rule.


    Jeff

  6. #36
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    Quote Originally Posted by Jeff Mann View Post
    I never stated/implied that you torqued the club with your fingers. I only stated that you palmar flexed your left wrist and angularly displaced the club. I think that Tapio is torquing the club with his fingers in his video demonstration.

    Jeff.
    How can you know what Tapio is doing with his fingers?

    Get with the program here or get lost.


    Jeff

  7. #37
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    Quote Originally Posted by Jeff Mann View Post
    BirlyShirly wrote-:

    "If I UD so that my ulna and radius are vertically aligned, and forearm and shaft are flat on the table top (difficult physically to do perfectly!) - then I can see flexion and extension moving the club back and forth, but the clubhead leading edge remains vertical. No axial rotation there.

    But with the wrist in RD - doesn't the same flexion and extension THEN result in axial rotation?

    Going back to my original example. With wrist in RD and clubshaft vertical - surely pronation and supination lay the clubshaft over but WITHOUT any rotation about the shaft?"

    I agree with his observations.

    Jeff.
    birly made only one observation, and posed two questions. Your post that you agree with his "observations" makes no sense. Try again.


    Jeff

  8. #38
    Jeff Mann Guest
    Quote Originally Posted by Jeff Martin View Post
    birly made only one observation, and posed two questions. Your post that you agree with his "observations" makes no sense. Try again.


    Jeff
    I interpret BirlyShirly's post as being reflective of his personal experience and I presume that he is basically asking whether other forum members have the same experience. He can "correct" me if I have misinterpreted his post.

    Jeff.

  9. #39
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    Quote Originally Posted by Jeff Mann View Post
    Jeffy,

    If you want to ban me - go ahead. You are have the arbitrary power as administrator of this website.

    However, don't pretend that you are being neutral.

    My personal opinion can be tested by any golfer - by simply going through the motions.

    BirlyShirly described his personal findings in post #29, and you have not threatened him with expulsion because he expressed his personal opinion on what happens when one performs certain biomechanical motions. He didn't present "evidence" and he only made an assertion.

    Jeff.
    Wrong. birly described verbally his evidence, expressed his opinion based on that evidence, then posed questions seeking confirmation or correction.

    If I need to explain the difference between how he posts and you post, then this forum is not for you.


    Jeff

  10. #40
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    Quote Originally Posted by Jeff Mann View Post
    Then, using that same logic, this forum is also not for you - because you post like me, and not like BirlyShirly did in that particular post.

    Jeff.

    Unsubstantiated opinion, no evidence.


    Jeff

  11. #41
    TeeAce Guest
    Quote Originally Posted by footwedge View Post
    @ Tapio, In the video when you showed supination you were actually doing it with your wrist in extension.
    Footwedge, that was pure supination and real supination without any other action. As well the first one in video was 100% pure palmar flexion. I think something is still confusing you in those terms, because PF would never lay back by PF at that position, no way for that. In PF fingers rotate of course and that rolls the shaft. That's pure geometry that it has to happen and that's why it closes the face.

  12. #42
    TeeAce Guest
    Quote Originally Posted by Jeff Martin View Post
    How can you know what Tapio is doing with his fingers?

    Get with the program here or get lost.


    Jeff
    I know exactly that I did nothing with my fingers, and it's not even possible. They move of course when wrist bends that way and when the hand is perpendicular to the shaft, it rotates shaft 1=1. If the shaft would be parallel to the fingers / hand, it wouldn't rotate. That angle in connection makes PF closing the face and it's much more geometry than biomechanics at that point.

  13. #43
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    Quote Originally Posted by TeeAce View Post
    Footwedge, that was pure supination and real supination without any other action. As well the first one in video was 100% pure palmar flexion. I think something is still confusing you in those terms, because PF would never lay back by PF at that position, no way for that. In PF fingers rotate of course and that rolls the shaft. That's pure geometry that it has to happen and that's why it closes the face.
    I have to disagree, if you do pure flexion from an extension position the club has to go back it has no choice. Also I can do it without rolling the face closed.

  14. #44
    TeeAce Guest
    Quote Originally Posted by footwedge View Post
    I have to disagree, if you do pure flexion from an extension position the club has to go back it has no choice. Also I can do it without rolling the face closed.
    In that case you don't do pure PF. Think about at what position the axle is in the wrist for PF. and look at my video the moment I show pure PF without club and keep also your forearm and back of your left hand on same line like I do.

    Or do one simple test: Lift your left arm to front of you and parallel to the ground left palm facing away from target and close your fingers. Your thumb should be now pointing away from you and perpendicular to the target line. Now if you do pure PF, the thumb will turn so that it's pointing right away from the target and it has rotated about 90 degrees, as we your fingers has rotated that way. Now if you put shaft inside of your hand and pointing up it will be perpendicular to your fingers and if you check what happens to the shaft with that movement, it rotates 90 degrees as your fingers and thumb.

    In Jeffs pictures there is much more happening than PF at the same time, so that would make different result.

  15. #45
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    @ Tee The way you are doing it the face is unuseable to play a golf shot you would hit yourself in the right shin. You can P.F. without making the face roll closed, that's the way to do it, because if you think you have no supination while you are doing your version of P.F. and the face is already ROLLING to a closing position WTF is going to happen if you also supinate later? YOU WOULD HOOK IT OFF THE PLANET! Why is the face rolling to a closed position if you are just pure P.F' in?

    What happens to the face when you do pure supination just before impact, does it close, does p.f'ing at that same time change anything or is the face still ridiculously closed just from the supination alone and then also delofted by the P.F'ing?

    I'm not confused about any of it!
    Last edited by footwedge; February 29th, 2012 at 01:14 AM.

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