COAM only applies to systems that are subject to a "CENTRAL" force. A central force is one which is directed through the axis of rotation. In the youtube Jeff attached, the spinning device is compressed and stretched by force with is acting THROUGH the axis of rotation. That is a central force.
Its would be impossible to argue that the forces generated by a golfer's muscles during the golf swing gestalt act in a direction which is through the "instantanous" center or axis of rotation. Therefore usage of the term COAM when discussing golf is wrong. COAM does not apply to the golfswing contrary to what some authors and their experts would have us believe.
no_mind
Originally Posted by Mike O
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.
COAM only applies to systems that are subject to a "CENTRAL" force. A central force is one which is directed through the axis of rotation. In the youtube Jeff attached, the spinning device is compressed and stretched by force with is acting THROUGH the axis of rotation. That is a central force.
Its would be impossible to argue that the forces generated by a golfer's muscles during the golf swing gestalt act in a direction which is through the "instantanous" center or axis of rotation. Therefore usage of the term COAM when discussing golf is wrong. COAM does not apply to the golfswing contrary to what some authors and their experts would have us believe.
no_mind
nmgolfer what about using certain forces to shift the center of mass forward to create an "instantaneous" axis of rotation for the pelvic region?
Jeff,
T.P.I are selling K-vests now if they were smart wouldn't they realize you can't put 6 degrees of freedom data into 3 degrees of freedom technology. So their information is not applicable anyway so whats the point.
why do you think they can't apply a hand sensor it's six dof data not three dof to be able to do this?
Also you have to be able to measure in space( anatomical time). T.P.I can't measure in space.
now this is comical , I have to laugh here. So if they ever release the hand sensor for k-vest or arm sensor it will be guessing or summating.
So it's useless to us. We don't want guessing we want accurate data.
Jeff do you know what summating is, I know you never use to use this word until I started talking about it and educating people on what the word means. so I'm interested if you know what it really means or you just picked up this word by scanning my threads in other forums.
We still retain 6 dof application in our screenings for starters , how can you compare a 3 dof system to six dof are you serious.
were are talking about applications for the consumer here, T.P.I use 3dof k-vest, we use 6dof data
you can't compare the two nor will the kinetic chains be the same.
I think it is funny for application use T.P.I are trying to fit 6dof data into
3 dof data , this will happen when monkeys talk and pigs fly.
Makes you question the intelligence of T.P.I.
This can not be done unless you fudge the metrics like they did the first time round.
Last edited by biomechanic : 10-27-2008 at 10:45 AM.
I don't mean to be rude are you jeff's twin brother, the way you write and express yourself is very similar characteristics as Jeff's and to come forward like you did back Jeff on your very first post seems very odd to me.
who are you and what is your back ground, I'm interested
are you jeff's twin brother, the way you write and express yourself is very similar characteristics as Jeff's and to come forward like you did back Jeff on your very first post seems very odd to me.
who are you and what is your back ground, I'm interested
No relation. Perhaps that it seems to you we "write and express" ourselves in a similar manner is because we are both men of science albeit different fields of expertise. Academia has a way of homogenizing or standardizing if you will the mores and protocol for engaging in technical discussions.
It would be meaningless for me to tell you my background because background (resume) is not proof of a claim. Besides it really does not matter where or how one comes by their knowledge, only that it be factual. Although I am not an autodidactic (with respect to this subject), I hold nothing against those who are.
If I were to claim my statements are true on the basis of my background it would be an example of: ARGUMENTUM AD VERECUNDIAM or the "Appeals to authority" logical fallacy.
Appeals to authority are always deductively fallacious; even a legitimate authority speaking on his area of expertise can get it wrong. The testimony of any authority is no guarantee that anything is true.
Jeff,
T.P.I are selling K-vests now if they were smart wouldn't they realize you can't put 6 degrees of freedom data into 3 degrees of freedom technology. So they information is not applicable anyway so whats the point.
why do you think they can't apply a hand sensor it's six dof data not three dof to be able to do this?
Also you have to be able to measure in space( anatomical time). T.P.I can't measure in space.
now this is comical , I have to laugh here. So if they ever release the hand sensor for k-vest or arm sensor it will be guessing or summating.
So it's useless to us. We don't want guessing we want accurate data.
Jeff do you know what summating is, I know you never use to use this word until I started talking about it and educating people on what the word means. so I'm interested if you know what it really means or you just picked up this word by scanning my threads in other forums.
We still retain 6 dof application in our screenings for starters , how can you compare a 3 dof system to six dof are you serious.
were are talking about applications for the consumer here, T.P.I use 3dof k-vest, we use 6dof data
you can't compare the two nor will the kinetic chains be the same.
I think it is funny for application use T.P.I are trying to fit 6dof data into
3 dof data , this will happen when monkeys talk and pigs fly.
Makes you question the intelligence of T.P.I.
This can not be done unless you fudge the metrics like they did the first time round.
Well well thats some interesting information to chew on..i guess thats what happens when the propaganda machine wheels are churning out the info with some serious money floating around
Pistol, I'm not sure I understand the question. Let me say this:
At every point in the golf swing the equations of motion apply ( F=ma and M = I alpha) These are of course three dimensional. Im mass in the parts of the system gets redistributed then that changes the moment of interia (I) in the second equation.
F (force) comes from gravity (small contribution minor really) and muscle contraction. When those force act on levers they cause Moments (M) which create rotation.
Muscles and gravity do not create central forces so as it is strictly defined in all physics/mechanics texts, COAM does not apply to the golf swing.
Originally Posted by pistol
nmgolfer what about using certain forces to shift the center of mass forward to create an "instantaneous" axis of rotation for the pelvic region?
Pistol, I'm not sure I understand the question. Let me say this:
At every point in the golf swing the equations of motion apply ( F=ma and M = I alpha) These are of course three dimensional. Im mass in the parts of the system gets redistributed then that changes the moment of interia (I) in the second equation.
F (force) comes from gravity (small contribution minor really) and muscle contraction. When those force act on levers they cause Moments (M) which create rotation.
Muscles and gravity do not create central forces so as it is strictly defined in all physics/mechanics texts, COAM does not apply to the golf swing.
What about shear forces through the feet and ground Nmgolfer?
Nmgolfer whats your opinion of TPI kinmematic Sequence and K-Vest?
What about shear forces through the feet and ground Nmgolfer?
Well there are definitely shear force going on there but they arise as a reaction. Other forces (from muscles) need be reacted to the ground by way of normal and shear forces lest we land on our butt.
Still don't get where your're going with this. A diagram might help.
Originally Posted by pistol
Nmgolfer whats your opinion of TPI kinmematic Sequence and K-Vest?
I'm a bit amused by all of it. If you've read that other forum (before the Manz deleted all of my posts that is) then you already know my answer. Lots of buzz words but from my vantage... very little substance and virtually nothing that's going to help your average golfer.
Frankly its not exactly clear to me what exactly it is they are trying to sell... that is...what problem it is they are trying to solve. If its not just technology for technology sake one thing is clear... they are leaving their potential customers with mistaken impressions with regards to what is and is not happening durning the swing. I assume you are familiar with the term "snap your chain"?
Hybrid Mode
