the COAM myth

Re: the COAM myth

Postby lagpressure » Sat Dec 19, 2009 9:43 pm

Those are great pics Two..
thanks for sharing..

Sure, the hands to slow in their tangential travel, but what we don't see is the pick up speed of their uncock and rotation, or what we do in our module #1 work. The hands can actually become more active in a rotational way, even though they do slow down in the tangential arc of their travel..

Nothing wrong with understanding this stuff...
User avatar
lagpressure
Site Admin
 
Posts: 8191
Joined: Thu Jun 04, 2009 12:50 pm

Re: the COAM myth

Postby mandrin » Sat Dec 19, 2009 10:29 pm

twomasters wrote:Here's 2 classic multiflash photos of the golf swing-- is this in tune with your diagram Mandrin?

This is from a book I dug out that I have. It is called The Four Magic Moves To Winning Golf by Joe Dante published in 1963. It has an entire chapter on COAM and is an interesting read. i will try and type it all in when i get around to it- but wanted to post the pics for now. Thought it was way ahead of it's time for being an almost 50 year old book...
by the spacing of the hand and sleeves- you can see hand/arm slowdown approaching impact and then hand/arm speedup again--- obviously this is only one golfer but the chapter spells out more which i will add later

I'm not an expert by no means on it-- just thought it intriguing to rip this book from my shelf to look at and there it was with an entire chapter about COAM which i had never heard of before until the last day or so reading this part of the forum


twomasters,

Indeed, Joe Dante's book, – 'FOUR MAGIC MOVES To Winning Golf' - is way ahead of its time, with a serious effort to try introduce science into golf instruction. However the explanations of the down swing given in chapter 7 using COAM are erroneous for the reasons spelled out in the opening post.

It has become with time normal in golf instruction books /articles to state that COAM rules the down swing without any second thought. It is certainly a good thing to try to explain golf using science, but science is not some flexible matter pliable in any direction. It has its rules and definitions which are rather strict.

The correct scientific approach to explaining the possible slowing down of the hands resides in the consideration of the interaction of linked masses, the kinetic chain action - a typical multibody dynamics problem. Even considering the very simple double pendulum swing, such as is the case for an Iron Byron, it is way more complex than most would suspect.

However, not easy, but by properly applying a torque, starting somewhat modestly and peaking sharply close to and through impact one does not necessarily have this slowing down of the hands during impact, even creating possibly some positive acceleration. COAM adepts would be completely mystified with such a swing, not knowing where to go with their theory. ;)
User avatar
mandrin
 
Posts: 196
Joined: Mon Oct 19, 2009 8:21 pm

Re: the COAM myth

Postby eagle » Sun Dec 20, 2009 3:16 am

lagpressure wrote:Those are great pics Two..
thanks for sharing..

Sure, the hands to slow in their tangential travel, but what we don't see is the pick up speed of their uncock and rotation, or what we do in our module #1 work.
Nothing wrong with understanding this stuff...


That was a lightbulb...."but what we don't see is the pick up speed of their uncock and rotation"....

Once again, I've been looking at these pictures for years and never saw /considered what you said here. Thanks!

I have never seen Iron Byron, in person. Does where "his" lever attaches to the club rotate and uncock like the wrists?.....if not, is this not a serious fallacy or drawback in using him as a model of the golf swing?....aren't there several other problems....Might be a good thread..."Iron Byron's deficiencies as a model"

Iron Byron is getting pretty old...looks like someone with engineering and fabrication skills could create something that jives more with reality.
User avatar
eagle
 
Posts: 1156
Joined: Thu Oct 15, 2009 7:34 am

Re: the COAM myth

Postby Styles » Sun Dec 20, 2009 12:16 pm

lecoeurdevie wrote:But then again what's money anyway, the only reason I turned pro was for the free shoes..


what size feet you got?

I have 10.5 UKs that would love a set of (slightly) used FJ Classics :D
Styles
 
Posts: 598
Joined: Wed Jun 17, 2009 6:29 am

Re: the COAM myth

Postby mandrin » Sun Dec 20, 2009 4:14 pm

twomasters,

COAM - conservation of angular momentum.

Read above slowly and carefully – what does it say?

It does refer to angular momentum being conserved.

What does that mean?

It means having a certain amount of angular momentum to start with and keeping it constant thereafter.

A golfer however is not conserving but instead generating angular momentum.

A golfer starts without any angular momentum whatsoever and is very busy generating angular momentum in the down swing.

Conclusion: COAM does not apply to a golf swing.

The usual examples taken to justify COAM in golf, such as rotating chairs, figure skaters, divers, etc., are indeed all subject to COAM - but a golfer, however, is not !!

To be able to use COAM requires two conditions to be satisfied:

    1) a closed system - no external forces.

    2) a certain amount of angular momentum to be conserved.

A golfer does not satisfy neither of these two conditions.

One can twist things any way one chooses it does not change these very simple basic facts.



There is another frequent misuse of COAM. It is usually taken as being at cause for the release. It is not. Forces/torques are at cause not angular momentum.

If I make a fire the close by air molecules start moving frantically around. This is reflected in a higher temperature. It is the fire being cause for the increased molecular motion not the temperature.

Similarly, torques/forces lead to motion which is reflected in an increasing angular momentum. Hence forces/torques are at cause, not the angular momentum, being at effect.

Angular momentum in effect depicts a particular characteristic state of a system, i.e., the motion and the mass distribution of a particular system.


I like to emphasize that 'conservation of angular momentum' is one of the most fundamental laws in physics, even more so than Newton's laws, as it extends equally to, and is valid in, atomic and nuclear physics. It is a scientific law not a golf rule and not flexible in its application.
User avatar
mandrin
 
Posts: 196
Joined: Mon Oct 19, 2009 8:21 pm

Re: the COAM myth

Postby Steb » Sun Dec 20, 2009 6:10 pm

mandrin wrote:twomasters,
To be able to use COAM requires two conditions to be satisfied:

    1) a closed system - no external forces.

    2) a certain amount of angular momentum to be conserved.

A golfer does not satisfy neither of these two conditions.


Whereas the golf swing from start to finish is not a closed system, analyzing the motion muscle fibre by muscle fibre in isolation would indeed show miniature closed systems. A muscle generating motion in some way, momentum carrying that motion through after the muscle has relaxed. Another muscle fibre might be working concurrently or taking over, but COAM does apply to that mini system viewed in isolation. As you say, it's a fundamental law of physics--it must apply to everything. COAM is existent in the golf swing.

But just the not the way it's usually tossed around. The example of throwaway in the golf swing leading to poor clubhead speed does have COAM at work on the existing momentum of a member after power has been cut from it, but as we're adding more power in during our downswing plus the external force of gravity is always present, the biggest principle at play is simple leverage.
Steb
 
Posts: 797
Joined: Tue Sep 29, 2009 5:42 am

Re: the COAM myth

Postby mandrin » Sun Dec 20, 2009 7:26 pm

Steb wrote:
mandrin wrote:twomasters,
To be able to use COAM requires two conditions to be satisfied:

    1) a closed system - no external forces.

    2) a certain amount of angular momentum to be conserved.

A golfer does not satisfy neither of these two conditions.


Whereas the golf swing from start to finish is not a closed system, analyzing the motion muscle fibre by muscle fibre in isolation would indeed show miniature closed systems. A muscle generating motion in some way, momentum carrying that motion through after the muscle has relaxed. Another muscle fibre might be working concurrently or taking over, but COAM does apply to that mini system viewed in isolation. As you say, it's a fundamental law of physics--it must apply to everything. COAM is existent in the golf swing.

But just the not the way it's usually tossed around. The example of throwaway in the golf swing leading to poor clubhead speed does have COAM at work on the existing momentum of a member after power has been cut from it, but as we're adding more power in during our downswing plus the external force of gravity is always present, the biggest principle at play is simple leverage.

Steb,

Let's imagine that I have you suspended in a harness above the ground. I leave you play as long as you wish with your muscle fibres and miniature closed systems. How does it feel hitting the ball this way with all the COAM at your disposal which you feel is acting from fibre to fibre? ;)

You might also have a look at a previous post on the same subject - Analysis of conservation of angular momentum using model including ground reaction force
User avatar
mandrin
 
Posts: 196
Joined: Mon Oct 19, 2009 8:21 pm

Re: the COAM myth

Postby Steb » Sun Dec 20, 2009 10:18 pm

I neither said or implied COAM acted fibre to fibre, for that makes zero sense, nor did I say or imply COAM powers the swing, an equally ridiculous concept. Angular momentum does not pass from one 'thing' to another, COAM is an inherent principle within the 'thing' itself. I know you know this.

Every object in this world that has an angular momentum will obey the principle. If someone wishes to introduce an external force to the object, then that is an additional, associative effect layered on top. The external force will change the angular momentum so overall angular momentum of course will not be conserved, but COAM is still having a component effect on the object's initial condition momentum.

Is COAM of any relevance to the golf swing? No. Does it exist in the golf swing? yes - it's exists in anything moving with angular momentum.
Steb
 
Posts: 797
Joined: Tue Sep 29, 2009 5:42 am

Re: the COAM myth

Postby mandrin » Mon Dec 21, 2009 10:32 am

Steb wrote:I neither said or implied COAM acted fibre to fibre, for that makes zero sense, nor did I say or imply COAM powers the swing, an equally ridiculous concept. Angular momentum does not pass from one 'thing' to another, COAM is an inherent principle within the 'thing' itself. I know you know this.

Every object in this world that has an angular momentum will obey the principle. If someone wishes to introduce an external force to the object, then that is an additional, associative effect layered on top. The external force will change the angular momentum so overall angular momentum of course will not be conserved, but COAM is still having a component effect on the object's initial condition momentum.

Is COAM of any relevance to the golf swing? No. Does it exist in the golf swing? yes - it's exists in anything moving with angular momentum.


Steb,

I might have interpreted what you are saying perhaps not quite the way you intended it. But normally one does not analyze a golf swing thinking in terms of individual muscles fibres. One step further and we are going to be working on a molecular scale. ;)

Hence in your words to avoid any misinterpretation:

“ ....nor did I say or imply COAM powers the swing, an equally ridiculous concept. “

“ Is COAM of any relevance to the golf swing? No.”


It seems therefore that we are in total agreement. COAM is neither causal nor relevant in a golf swing.

Hence you therefore also totally disagree with instructors misusing COAM, such as for instance Joe Dante, who considers COAM to be the essence of the golf swing in ' FOUR MAGIC MOVES To Winning Golf ', since you are convinced that :

1) it is ridiculous to consider that COAM powers the golf swing, and

2) COAM has no relevance to the golf swing.

Glad too see someone in total agreement. Very few are going to agree with either you or me.

It is so difficult to let go of this believe in COAM as it seems so natural as explanation and having being repeated so often over the years by so many people.
User avatar
mandrin
 
Posts: 196
Joined: Mon Oct 19, 2009 8:21 pm

Re: the COAM myth

Postby biomechanic » Tue Dec 22, 2009 2:37 am

Mandrin,
What is your point and what has this accomplished... Is this thread really going to help golfers get better...
Who said coam powers the golf swing and who are you referring too...
There are two speeds linear speed and angular speed of the club.... If you have deceleration of angular speed you will have poor ball compression...
Not sure who your referring to, who believes coam powers the swing....
One minute you say there is no coam in the golf swing what so ever and then you say there is some coam and has no effect on the golf swing...

What is your point and who really cares.... how is this helping people play better golf....
Do you think golfers give a dam about coam .... all they care about is what ever works for them so they can play better golf...
How about focusing on something positive for a change and look at how can golfers swing the club move effectively and become more consistent...
Why waste time and energy on this for... what will this achieve ... absolutely nothing...
biomechanic
 
Posts: 75
Joined: Thu Oct 15, 2009 5:29 am

PreviousNext

Return to Top Threads (2000 Club)

Who is online

Users browsing this forum: No registered users and 2 guests

cron