Quote By Jeff "However, I cannot understand how COAM can be involved in a system that is actively producing more energy. The concept of COAM only applies to a system where the amount of energy inputted into the system is fixed and the entire system either slows down or speeds up dependent on the distance of the mass of the revolving object from its central axis."
Just a clarification- For anyone studying movement and getting the wrong impression of the above quote.
1) When you consider the concept of Conservation of Angular Momentum as the total angular momentum always staying the same in a closed system and therefore, if you move mass further from the center of rotation then there is a slowing of the rotational speed- then you might agree with Jeff's quote and say " That doesn't exist in a system where you ARE adding energy.
2) When you consider the aspect of Conservation of Angular Momentum - that in ANY rotating system - when you move mass further from the center of rotation- that has a slowing effect on the rotational speed- you'll see that the principle stands true whether you are in a closed system or system where you are adding energy. The only issue is - how much mass has moved, how much slowing is that creating and when, where and how is the added energy affecting the overall result. When you keep that perspective in mind - then Jeff's quote can be very mis-leading, confusing, etc.
In summary, your thoughts on this thread Jeff are definitely worthwhile areas to explore - I just thought I would attempt to clarify this one area that stood out for me. The principle of conservation of angular momentum exists in every rotating system.
__________________
Life Goal- Developing a new theory of movement based on Brain Science
Interests - Dabbling with insanity
Hobbies- Creating Quality
Mike - I generally agree with your position that COAM could theoretically be acting on a rotating system while energy is still being inputted into the system - like that rotating structure in the U-tube demo. However, it would be very difficult to quantify the effect of COAM on the speed of rotation of the entire system while the person is actively spinning the rotating system. Secondly, the principle of COAM applies to the entire rotating unit (how its overall speed of rotation is affected by the distance its mass moves away from its central axis of rotation) and it has nothing to do with the transfer of energy from one moving body part to another body part. In the kinetic link theory expounded on the Xenolink website, there is an evidence-unsupported belief that energy is transferred from the pelvis => shoulders => arms via "a conservation of momentum" principle that involves a braking phenomenon whereby the slowing of rotation of one body part causes another body part to speed up. . Can you understand the physics/biomechanics that could underlie such a "belief". I can understand the kinetic link working in a snapping whip, whereby the sudden braking action of the rope handle of the whip transfers energy down the length of the whip to its peripheral end thereby causing the peripheral end to speed up. However, the whip is a totally inert physical structure that doesn't generate power within itself - it simply responds to the hand movement of the person wielding the whip. During a golf downswing, a golfer is actively contracting a multiplicity of muscles that cause the pelvis and shoulders to independently turn at a certain rotational speed. There is certainly an interaction between the rotating pelvis and the rotating upper torso - in the sense that the movement of the lower torso transmits physical forces to the upper torso via the spine and truncal musculature/ligaments. However, the golfer is also actively rotating the upper torso during the downswing and it would require some very sophisticated experimental testing (using muscle probes in a variety of truncal muscles) to determine how much of the upper torso's rotational speed is due to active torso muscle contracting versus passive physical forces transmitted from the rotating lower torso. I have never heard of any researcher performing that type of experimental testing. Have you?
Regarding your concept of the TGM pivot-stroke swing - do you think that the pelvis/shoulders/arms are rotating at roughly the same speed in the early downswing - before the lead arm reaches the parallel-to-the-ground position; or do you believe in the kinetic link theory where there is a time-sequential transfer of energy that causes the pelvis to move first, the shoulders second, and the arms third with each sequentially moving part maximally rotating at exactly twice the speed of the preceding moving part?
I think that the critical issue is not Welch's proprietary software program that measures the angular velocity of different body parts during the downswing. I think that the critical issue is the underlying physics/biomechanical principles that underlie Welch's thinking when he eventually interprets his measured results. That's what bothers me! It is his underlying ideas regarding "conservation of momentum and summation of speed" due to a braking phenomena that bother me, and his consequent idea that each rotating body part must get sequentially accelerated to exactly twice the speed of its preceding rotating body part via this braking phenomenon.
I think that the critical issue is not Welch's proprietary software program that measures the angular velocity of different body parts during the downswing. I think that the critical issue is the underlying physics/biomechanical principles that underlie Welch's thinking when he eventually interprets his measured results. That's what bothers me! It is his underlying ideas regarding "conservation of momentum and summation of speed" due to a braking phenomena that bother me, and his consequent idea that each rotating body part must get sequentially accelerated to exactly twice the speed of its preceding rotating body part via this braking phenomenon.
Jeff.
I see your arguement Jeff but like I said ..the best bet is to go and check him and his system out and get the information ..then make a "scientific review" of his concepts rather than present a TPI view of possible weaknesses in his system
Regarding your concept of the TGM pivot-stroke swing - do you think that the pelvis/shoulders/arms are rotating at roughly the same speed in the early downswing - before the lead arm reaches the parallel-to-the-ground position; or do you believe in the kinetic link theory where there is a time-sequential transfer of energy that causes the pelvis to move first, the shoulders second, and the arms third with each sequentially moving part maximally rotating at exactly twice the speed of the preceding moving part?
Jeff.[/quote]
The problem i see here is it depends on the definition of when a backswing has finished and a downstroke has started ..Kinetic Link may have a different view on this opposed to TPI..and which player is tested.
For instance ..the hips can have a running start on the shoulders due to the pressure being moved to the reAR foot and the center of mass being in front of the pressure being shifted to the rear foot and this can occur in the backswing..so the shoulders have some catching up and then of course so do the arms due to how Far they have to travel
Pistol - you wrote-: "The problem i see here is it depends on the definition of when a backswing has finished and a downstroke has started ..Kinetic Link may have a different view on this opposed to TPI..and which player is tested."
Your belief about different definitions of the end-backswing may be true, and that's why I believe in standardised definitions. Cheetham, of TPI, has recently accepted what I regard as the only scientifically-supportable definition for the end of the backswing - when the club changes direction. All the latest TPI graphs now use that strict definition for the top/end of the backswing - rather than vague criteria eg. when the shoulders stop turning or when the pelvis reverses direction and starts to move forward (a phenomenon which actually may occur during the backswing in many good golfers).
Rhythm - I think that your questions are partly meaningless, and I don't know what's your real agenda.
When you ask "how do I come to my conclusions" it is like asking a person how he thinks with respect to "cause-and-effect" relationships. I have a certain way of personally solving the issue of "cause-and-effect" relationships by using a multiplicity of scientific principles eg. Humean logic relating to contiguous events in the absence of confounding variables, Popperian experimental testing procedures that rigorously test a theory for its falsifiability quotient, Haackian criteria relating to concordance between different theories in a particular field of science (web of belief ideology).
This is a worthwhile discussion, but it is not housed appropriately in the forum TGM Advanced. Please hasten all posts and participants to an identically-titled forum in The Lab.
Rythm,
Jeff has no qualifications, he claims himself to be interpreter, he pulls stuff off the net and adds his twist, the reason he doesn't understand what chris does is he hasn't no understand or education in biomechanics.
Now Every one I left T.P.I cause their data was wrong and I destroyed golf swings in the process, there data doesn't measure up to be right.
the human body doesn't function the way they are claiming.
They can't measure hitting and swinging, the kinematic graph doesn't replicate what a student is truly doing in their swing,, not at all no comparision.
SO I LEFT , THEY ARE THE WORST BIOMECHANICS RESEARCHERS GOING.
There K-vest is a joke the data is so far out it's beyond a joke.
when you have students over the top the vest is lighting up green
you can't measure the so called T.P.I kinematic sequence.
all you can measure is hips and shoulders.
I have first on experience and worked for K-vest T.P.I ,
I have full understanding inside out of the technology used and was highly trained.
From a hands on experience and screening students the results told the story,
the metrics were terrible. I had to change my metrics on my vest to the original metrics K-vest first use, it was that bad.
T.P.I can't comment on what we do they have not the technology to measure be able to compare.
And this is why jeff can't understand how we do it.
And we aren't going to put it out for the public either, so people can steal the technology
MikeO is right you can measure coam if you have the technology to do so.
T.P.I can't cause they have not the technology, they have a cheap 6 dof system which can't measure antomical time (in space) they are surmating their metrics , guessing another words. using maths
They also measure from vertical position, not as a player stands in golf swing position, this leads to data being further out.
Our difference is we can measure anatomical time we don't use sumating
T.P.I can't measure anatomical time (in space) and they do sumating. (guessing)
of coarse you will get different out comes they are guessing we aren't.
If you ever want to get further from the truth in how a swing works in biomechanics follow T.P.I
Hybrid Mode
