The point is: If I throw a ball to you just out of your reach, you move to catch it based on where you hand needs to be. I would doubt that you would shuffle, twist or contort yourself or think about what your body is doing. See ball- catch ball. I am not discussing chains, sequencing, etc.
My job as an instructor is to help people learn and enjoy the game. If I can do that and help them reduce or avoid injury because some other teacher gave them the impression they need 120 degrees of shoulder turn, then that is what I will do.
Dr. Seaman did his research and it's not my job to prove it is credible because someone else doesn't like it. If you or anyone else wants to take the time and refute his findings then knock yourself out.
__________________ Hitting the Ball is the easiest part of the game-hitting it effectively is the most difficult. Why trust instinct when there is a science."1-G.
"agree with shear forces"????? What kind of ridiculous idiocy is that? Its like saying you agree the sky is blue....
Admit it Bio-BSer, you're a technician whose been taught how to perform a measurement, but you're clueless when it comes to interpretation of results.
Its obvious y what you've written (here and elsewhere) that you have no clue what shear force is let alone a dof or COAM. And the fact that you are such fawning sycophant of homer's proves that you are completely unaware how riddled with technical error his work really is.
But what's worst is that think the spine is designed for twisting and or that there is ANY power to be had by torquing the torso. That is down right scary. Mark my words you will be sued for injuries you will cause.
Lasty you may think being an a-hole is all "just fun and games" but where I'm from its just BEING AND A-HOLE.
Originally Posted by biomechanic
No mind golfer,
depends how you take an insult, in australia we call this Sh''t stirring, stirring your mates up and getting a reaction, it's all fun and games.
I never take what you say personally, I laugh at your insults.
If you agree with shear forces , then your admitting your agreeing with conservation of monentum, and coam.
how you think normal and shear forces work, conservation momentum.
Thank you for the kind words Coop. There was a time when that forum was open to all ideas but not anymore. When they went to "rev. 3" or what ever it is, apparently they closed the door to all but the owner's personally espoused beliefs. This I knew (or at least suspected) but I spoke up anyway and for that I take personal responsibility. I try not to let any of this get personal but when the ad homenim starts flowing... I'm human.
Fact is some of these guys (especially those starting the arguments) are simply marketing. They are promoting what ever snake oil it is they think might get them noticed, invited to speak, write for a periodical or perhaps even just con the next client into signing up for lessons (or measurements). To them its "just business" or as one says, "good fun" which is too bad for everyone.
Quote:
"Golfswings are kinetic chains but "kinetic chains" are merely descriptions of types of movement and/or sequencing of movements within a given activity. I don't think "kinetic chains" describe power generation or power enhancement."
Exactly! We're 100% in agreement. Your 4th paragraph below is spot on in my opinion.
Lastly Coop I also think there is much work yet to be done in understanding the bio-mechanics of the golf-swing and it is people like you that will get it done. (You are the author of that highly regarded book are you not... well done!)
Originally Posted by coophitter
Hey NM, I think you are the guy who told someone on another forum not to lie about moving objects on car dashboards to an English major golf pro who was obviously quite confused and leery about the professional advice and information to "use your pivot to snap your Kinetic Chain, and to assist your arms, hands, and club with creating the proper D plane for the selected shot. Everything else is show biz." They deleted all your posts and maybe some other poster's posts as well, so I'm not sure it was you. Thanks for sticking up for me if it was indeed you.
Anyway, my posts to that site haven't been deleted and since the time you were wiped out, I've continued to post there to implore anyone to explain to me in the Queen's English what the hell a "kinetic chain snap" is and how you can use your "pivot" to do it. Well I haven't gotten any good answers except that I am wrong to even cast a doubt in the direction of pivot induced kinetic chain snapping since some PHD clearly posted and explained a diagram of 16 or 8 piece linked chains to show that kinetic chain snapping is not only possible but likely necessary to generate the adequate or "missing?" horsepower that Cochran and Stobbs struggled to substantiate in order for good golfers to hit balls as far as they do..
I have been studying biomechanical research concerning the golfswing for many years and I've yet to uncover solid evidence to support the idea that power in good golf swings is generated by rotational movements of the pelvis and spine. Of course these rotations are necessary to create good backswings, good transitions, and good downswing posturings to strike the ball well, but I've never heard of these rotations (especially hip/pelvic rotations) as being able to generate or store significant power for golf. In fact I'm struggling to find any credible biomechanical literature wherein twisting, or coiling, or winding up, or pivoting of the pelvis and torso are used to describe dominant power generation in any powerful forms of human locomotion.
The credible research that I have studied strongly suggests that the difficult to describe lateral slide and resultant weight pressure shift and slight pivot of the hip girdle toward the target and onto the left leg is responsible for generating the real power for good golf swings. The research always describes this lateral pelvic shift/slight rotation as occurring BEFORE the completion of the backswing, and the research generally claims that this movement serves two critical functions in good golf swings: First, it is opposed by the grounded left foot and this opposition promotes subsequent rotation of the pelvis to the left about and above the left femoral head, which allows the pelvic girdle to rotate and face the target by the end of the swing. Second, it serves to pre-stretch principle upper extremity adductors (primarily pectoralis major and latissimus dorsi) before golfers initiate the downswing by contracting those muscles. More recent research shows that this PRE-DOWNSWING lateral weight pressure shift and slight leftward rotation of the pelvic girdle likely pre-stretches the right external oblique muscle as well, which will subsequently contract and initiate torso rotation to the left side on the downswing. It is the stretching and subsequent contraction of these muscles that enhance or harness the power created by the initial PRE-DOWNSWING lateral shift and slight rotation of the pelvis. I'd like to throw in that I hope most golfers have effectively hinged their right forearm about its elbow and both hands about their wrists, thus pre-stretching the right triceps and both sets of appropriate forearm muscles to contract on the downswing to further and dramatically enhance or harness the power generated by the initial PRE-DOWNSWING lateral shift and slight rotation of the pelvis.
I interpret from your posts that you basically espouse the validity of the research that I have studied. None of this research describes COAM or pivot induced kinetic chain snapping as enhancing, harnessing or "overpowering?" power generation. Golfswings are kinetic chains but "kinetic chains" are merely descriptions of types of movement and/or sequencing of movements within a given activity. I don't think "kinetic chains" describe power generation or power enhancement.
I think a lot of good people have been convinced that the lateral pelvic shift/rotation thing STARTS the downswing instead of PRECEDES it. If measurements are taken of a PRECEDING THE DOWNSWING MOTION as being a START OF THE DOWNSWING motion, then those measurements will likely be compared to a backswing that hasn't ended yet - and huge brain snaps will occur in the wrong direction as a result.
By the way, Tiger is the best at slowing and stopping his pivot and arms after he starts the downswing, especially when he hears a camera click, but alas, the club never hits the ball because it stopped too!
NM, thanks for sticking to your guns. I don't want to write any more posts for a long time. If anyone can be right concerning this subject, I firmly believe that it is you. Don't let it go to your head though!
The point is: If I throw a ball to you just out of your reach, you move to catch it based on where you hand needs to be. I would doubt that you would shuffle, twist or contort yourself or think about what your body is doing. See ball- catch ball. I am not discussing chains, sequencing, etc.
My job as an instructor is to help people learn and enjoy the game. If I can do that and help them reduce or avoid injury because some other teacher gave them the impression they need 120 degrees of shoulder turn, then that is what I will do.
Dr. Seaman did his research and it's not my job to prove it is credible because someone else doesn't like it. If you or anyone else wants to take the time and refute his findings then knock yourself out.
I never disputed seamans research, our biomedic engineer helped him do his research, his information came from the company I'm with.
At the end of the day he put his name on the book, look deeper and you will find where his research came from.
"agree with shear forces"????? What kind of ridiculous idiocy is that? Its like saying you agree the sky is blue....
Admit it Bio-BSer, you're a technician whose been taught how to perform a measurement, but you're clueless when it comes to interpretation of results.
Its obvious y what you've written (here and elsewhere) that you have no clue what shear force is let alone a dof or COAM. And the fact that you are such fawning sycophant of homer's proves that you are completely unaware how riddled with technical error his work really is.
But what's worst is that think the spine is designed for twisting and or that there is ANY power to be had by torquing the torso. That is down right scary. Mark my words you will be sued for injuries you will cause.
Lasty you may think being an a-hole is all "just fun and games" but where I'm from its just BEING AND A-HOLE.
Who mention twisting and torquing the body, sued for teaching people not to over twist and torquing their body be my quest to sue.
People develop the wrong perceptions of body rotations from glossy magazines. what the x factor thats destroyed more swings and injured more people, I agree go sue the x factor boys.
welldone to your letter from your biomechanists friend, he's right, it's called muscular loading, go to see he is on the right path. I sincerely mean this well done to him, he is on the money. I agree with him.
the chain is an indication to what the body is doing in a motion, all it indicates is rotational speeds, show's each segments acceleration and deceleration and if the segment are moving in the right sequence and whether the body segment is efficient and inefficient in their swing.
there is stability as well,muscular loading and club dynamics as well to consider, which we measure.
measuring shear force is also some thing we measure, we can tell you if they apply enough shear force or not enough.
No-mind golfer you may not agree on coam that's ok, but if we were to speak in person you would find we are on the same page on a lot of things.I like the letter you presented and liked what was said.
I would love to explain coam, but to put to paper is to hard to explain.
honestly send me a email and would love to organise a webinar and speak with you further. i would be happy to show you in depth what we do. how this is measured and why would you like to find out?
I thought that this thread was removed from the forum. I didn't realize that is was moved to this section.
Wow! It is good to see nmgolfer's posts again. I thought that he had disappeared from online golf forums. I especially like his sound argument that the logic of a poster's argumentative position depends on its intrinsic logicality (its intellectual coherence and its concordance with objective reality) and not on the "qualifications" of the poster.
I am not surprised that he found Biomechanic's posts of little value, and I am not surprised that Biomechanic thought he was a Jeff-clone.
Going back to the "facts" regarding the kinetic chain - I agree with nmgolfer that the kinetic chain and COAM doesn't apply to torso movements in a golf swing. However, I think that nmgolfer is wrong about two points.
1)I think that COAM does apply to the relationship between the movement of the left arm and the clubshaft.
2) I think that the the left arm slows down prior to impact.
nmgolfer only quoted one source that claims that the arms/hands do not slow down prior to impact - Nesbit's research study. However, there is substantial evidence from many other sources that demonstrate that the left arm/hands do slow down prior to impact.
An explanation of why the hands should be expected to slow down prior to impact comes from an understanding of TGM mechanics. Here is my personal explanation.
In a pivot-driven swinger's action, the pivot supplies swing power that is responsible for the release of PA#4. From then on, the body pivot motion does not affect power production because the PA release sequence is 4:2:3 and PA#2/3 are passive release phenomena. The club is an inert object that doesn't know from where the source of power is derived - it only responds to the pull force at the grip (exerted by the left hand). In that sense, the double pendulum swing model applies. The clubshaft is equivalent to the peripheral arm and only responds to pull forces exerted at the peripheral hinge joint (left hand), and the peripheral hinge joint only moves as fast as the central arm (equivalent to the golfer's left arm).
In a pivot-driven swing, the pivot supplies swing power that causes the release of PA#4. Once PA#4 has been released, then no more energy is imparted to the system of the flying left arm (from the central torque generator = body pivot motion) . In that sense the flying left arm is a motional system containing a "fixed" amount of energy. When PA#2 releases, and the clubshaft becomes more in line with the left arm, then the left arm must slow down. There are two valid explanations for this phenomenon. The one explanation relates to COAM.
Explanation number 1
If the left arm (central arm)/clubshaft (peripheral arm) is a system in motion, and there is a "fixed" amount of energy in the entire motional system, then the central arm must slow down if the peripheral arm speeds up - because energy moves from the center to the periphery.
Explanation number 2
Another way of understanding this COAM phenomenon relates to the distribution of the COG relative to the axis of rotation. If the COG of the entire motional system moves further from the central axis of rotation (which is the central hinge point from which the central arm is suspended in a double pendulum model), then the entire motional system must slow down. That's the explanation evoked by David Tutelman in his explanation.
I now believe that the hands slow down prior to impact (because the left arm slows down prior to impact) in an excellent golfer's swing and it's a good thing - because it allows time for release of PA#3 and the squaring-up of the clubface prior to impact.
Here is a capture image of Tiger Woods swing - videod at 4,000 frames/second. Every white dot joining those red lines represents 10 frames (1/400th second) and one can see that Tiger's left arm slows down just before impact.
There is one other unquantifiable factor that makes my COAM explanation far from full-proof.
The COAM idea is based on the belief that all the energy propelling the clubshaft is only passively derived from the left arm (according to the principle of COAM), and that the left arm derives all its energy via the release of PA#4. However, one needs to consider another factor - the role of left forearm muscles in actively releasing PA#2 and/or PA#3. If the left forearm muscles supply any energy to actively release PA#2 or PA#3, then the left arm may not need to slow down as much as predicted by the COAM theory.
B. J. Hathaway, G.S.E.B., M.C.I.
I sincerely mean this well done to him, he is on the money. I agree with him.
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