In a previous post being somewhat quick on the gun, I slipped into a habit I have since several years to refer often to kinetic energy and angular momentum together. It was not appropriate for this particular post and have edited accordingly. To avoid ambiguity I have reposted the edited post just below.
In answer to my post above biomechanic came back with his post just below. He does a bit of mud slinging for reasons which are uniquely his own. Such as suggesting that I really don’t know anything, should leave it to the experts like him, plucked from Wikipedia, etc… It is to fastidious to go into all of the details and correct him. I will do much better and show that he is wrong about angular momentum and let mathematics do the talking. My post above was basically a quick intuitive assessment of the matter of conservation of angular momentum. Just go to the bottom and you will find a clearcut mathematical substantiation. Just a note for biomechanic – don’t look again for any website, you won’t find it anywhere. I do my own thing, usually from scratch.
Biomechanic, so you believe that angular momentum is conserved. You make it clear that it is all very complicated and that one should leave it to you, since only biomechanical experts can unravel all the subtle and complex intricacies of it all. Well perhaps it might come as a surprise to you, but in a very short time I came up with a model, developed the mathematical formulation, and used it to analyze the issue of angular momentum in the golf swing. Now we have the very funny situation that I am telling you, and even proving it, using mathematics, that you, the expert, got it all totally wrong. Have fun, enter here.
PS: I did it all rather quickly so will be happy to explain any obscure point or text in the linked annex.
I readily accept your apologies. With regard to this forum. Indeed rather unique set of favorable conditions. It is up indeed to the members to use this tool with care so not to let it go into ego wrestling which happens so frequently. But a bit of sporty wrestling is like a little pepper and salt on food. It keeps you alert and alive
[i]biomechanic[/i] Why do you do this? Are you not aware that intelligence is judged far more on the questions that you ask than it is on the answers that may later be arrived at? The vast majority of answers that have ever been found have been found by those who asked the right questions. I suggest that you go back and read carefully what you have submitted (above) in a public forum. You have done yourself no favours.
What you are also offering here is the dictate that no student can ever exceed the performance of his/ her master. What an extraordinary dollop of horse shit!
You act rather like a duck on the opening day of the hunting season wandering around, looking down gun barrels, while holding a sign "I'm a duck".
You leave yourself open to instant rejoinders, one of which goes like this; [i]biomechanic[/i] if you are going to write in the public forum and criticize everyone else who does not submit to your obsessions, why don't you at least try to use some format that resembles the English language? After all, adequate use of the language involved could be deemed as fundamental to any public critic. I would suggest that it would be far more fundamental than having to qualify as a researcher/ teacher/ writer by having first have played to a scratch golf handicap.
In point of fact; I have met very few PGA teachers who could play off scratch!
You brought me to task, publicly, because I didn't ever play off a scratch handicap, which I didn't. Nor did I ever claim to, it is utterly irrelevant.
There were reasons why I didn't get there but I'm not going to bleat and bitch about how tough life can be. Shit happens! Get on with it and make the best uses you can out of whatever it is that you have left.
mandrin…
Just to clear up a small matter between you and I.
I’m an ex Police Officer who believed profoundly in what I did, more importantly, why I did it. In reality, I was retired, Injured on Duty, on a lifetime pension via Superannuation. All of which only means this;
I know, with an utter certainty, that not once in my 16 year career did I ever cause to be imprisoned, or otherwise penalized at Law, one individual that was not guilty.
I had a particular dislike for, contempt for, innuendo, the ‘implied’, changing the playing field to suit the needs of the investigator/ observer. Had I been otherwise I may well have ‘put away’ people who were not guilty. My particular hatred of the 'implied’ also relates back to the eternal public observation that, because a few Police are found to be guilty of corruption or the like, all of them must be. The sins of the very few, in nearly all walks of life, are far too readily taken as the corruption of all.
Your approach to me touched on that nerve and I reacted accordingly. Had you asked straight questions I would have responded quite differently.
In your last post directed towards me, your comment about mandrin and mandarin, with your attached barb, left you wide open to retort, in like kind, which you got.
A golden rule in life is; never presume anything!
Let’s leave it at that.
Cheers
Gerry
I don’t mind a bit of hustling. Got the impression you are somewhat similar. So it is all matched evenly. I have my style, you have yours. It is a matter of getting used to it. No harm done.
Funny thing this remark about madarin/mandrin. I am used to people doing all they can to belittle me as to the value of the bit of science I bring to forums. One of the more subtle ways it was done was to systematically use mandarin instead of mandrin and crack jokes related to it. So like you I came from a background with a ‘preprogrammed neuronal reaction pattern’ ready to spring into action. Very similar to a golf swing muscle firing sequence stored in the brains. One trigger and it is on automatic pilot.
This Aussie has been enjoying this forum, especially enjoying Gerry’s posts, but I have been constantly disappointed with the attacks and very poor grammar so typical of Bio’s efforts. I frequently backtrack and review some of Gerry’s posts, because they are usually helpful and insightful .
Perhaps Gerry didn’t even bother to maintain a handicap. That’s not important to me. I’ve read many golf books, seen many golf videos, and had my share of lessons and training aids. But I never actually understood my golf swing until I read “The Hogan manual Of Human Performance”. Now my golf swing is much simpler and much more effective, and my mind is now clear enough to allow me to focus on enjoying our great game .
Lads… As I remember it Bio has said a good few times that he had an accident that made him have to learn to walk, talk, read, and write again- looks like he’s doing a pretty good job if that’s the case. Lets stick to the golf, I’m sure if an English scholar came on here he’d be able to tear our ‘correctly written’’ posts to shreds. It’s starting to feel like Ramsey Street around here- I’m waiting for Madge Bishop and Mrs. Mangel to pop their heads around the corner
A golfer from the ground up is going from bigger parts to smaller parts – from hips/trunk/shoulders, arms to club and finally clubhead.
It is this feature which makes possible the peripheral velocity multiplication as is happening in a kinetic chain. Gerry is strong on this.
In science one often uses an equivalent simplified model to analyze the essential features of a more complex system.
Its does not have to be physically equivalent as long as it mathematically equivalent to the system one wants to analyze.
So I have taken a few coupled disks rotating on a common axis which are not quite a golfer but reflect nevertheless both physically and mathematically a golfer by going from heavy to lighter parts.
We are not after any precise conclusion only to establish a clear understanding of how valid is this general believe that angular momentum is conserved in a golf swing.
The systems of coupled disks is translated into a set of coupled differential equations which I can now solve for all kind of conditions which I might choose. Very flexible and very useful.
Hence, the mathematics reflects completely the physical reality of the disks, a true one to one relation. However mathematics is very easily manipulated but not so physical disks.
I imposed , in the mathematical model, the condition of one internal torque to act between any two adjacent disks and derived how the disks rotated and how the angular momenta of the disks and their total sum behaved.
From doing systematically these experiments it is readily derived that -
Angular momentum is not a constant in a golf swing as is universally accepted in golf kingdom.
Angular momentum is zero at the start of the down swing and steadily increasing.
Angular momentum is mainly first generated in the bigger parts and later on redistributed between the lighter parts, leading to velocity multiplication…
Angular momentum is not a cause for release as universally taught but an effect.
On the last point. If I heat up air with a flame, the increasing temperature is not cause but effect. Similarly when torques acting on mechanical systems causing rotation, angular momentum, like temperature, is effect not cause. Cause in a golf swing are the various torques. Kinetic energy and angular momentum, like temperature, are simply reflecting the values of certain defined parameters describing the state of a system.
If things still are clear as mud, just keep asking questions. I will do my best to answer.
The TGM position is that you need a flat left wrist (FLW) at impact. The terminology ‘Frozen Right Wrist’ is also used. Lots of other positions - teachers have advocated lashing the wrists through the ball etc. - are out there too.
I wonder if the TGM position encourages a bad mental attitude to golf - and suggest that while it may superficially fit the geometry, it does not help with good physics (power transmission along the chain).
If we are in the business of transmitting power, surely any attempt to ‘freeze’ or ‘maintain’ a flat left wrist can surely only result in power leakage?
Speaking of clearly written posts I don’t know how edit them or if you can so I’m going to ‘quote myself’
Mandrin,
Can you go into this statement a little more, it’s kind of vague and I’m trying to figure out if your equations are based on it being true. I’m not sold on the idea that movement starts from the ground, I think the ground receives movement through the feet and then multiplies it. On a very basic level the arms leave the body which has nothing to do with the ground yet their actions will affect the speed of the clubhead. Your model kind of makes sense if you were just assessing body rotational speed, and how to max that out, but even then a single axis of rotation is inaccurate imo. Then there are the subtle timing issues of when and where to accelerate in order to coordinate the opposing journeys of the body and arms/hands/club. I sometimes think that proving these ideas are games within games, kind of like fantasy football. They’re fun and can definitely be useful, but the more precisely they try to nail it all down and define it, the further they get from the truth of it all. But then again, I’m not a scientist!
B
Interesting question, Beez. I do agree that thoughts like ‘frozen’ contribute to the motion issues with TGM. I was trying to get some thoughts on this type of thing when asking about research into grip pressure changes through the swing but nobody took any bites. My thoughts would be that the FLW and BRW are the last links in the chain if internal to external acceleration and trying to form them in space prior to their moments robs you of that last crack of the whip. I don’t think their angles are ever constant.
B
Understanding the hands is understanding the difference between hitting and swinging.
Passive hands acting as hinges
or
Active hands working as vicious motors.
Hinges swing… motors hit.
Golf theorist will argue till the end of time about these two methodologies, until they clearly understand both protocols. Both have merit.
Either way, keeping the arms from moving too much laterally is beneficial.
I don’t like the TGM definition of hitting vs swinging being defined by right arm participation, passive or active. The big throw out to right field is a questionable method. It’s simply not consistent with the action of many great ball strikers… such as Ben Hogan.
Releasing the hands actively from P3 into impact has it’s complexities… and I focus a lot on this with my students.
Some like to argue that the hands can’t fire or be active, and this is true if you are swinging… you don’t want active hands… but hitting with active hands is a reality.
I can certainly hit a chip shot without moving my arms at all or my body. Hands would of course be active. If I fully cock my wrists to P3, with no lateral arm movement, I can actively rotate my forearms and uncock my wrists with muscular force and strike the ball. This could be done without any building of angular momentum from the top of the backswing.
Now I can add to that by taking a backswing, like a jump start… deliver that “set” triangle to P3 and fire actively… and hit…
but on the other hand, I could crank a bunch of speed from the top driven by a quick rotation of the torso with passive hands and guide a higher speed delivery into P3, then forget the hands being motors, and let them act passively as hinges, and let all the physics of angular momentum and CF do their thing, and strike the ball that way.
In my study of the swing, whether it be reading from books or listening to various instructors, or talking to good players, or from my own experimenting, application and personal sensations and visual results, golfers seem to fall either left or right on either side of the hit- swing fence.
To me, there is zero confusion. Clear as a blue sky on warm summer day. When someone starts talking swing theory, I can tell pretty fast which side of the tracks they are laying their bed.
Problems occur when you start confusing the two methods. If you are on the track, get off it, and run either way to safety… before you get run over by the train of confusion.
After reading Gerry’s book, have to say I’m feeling it the second (CF) way BIG TIME at the moment. Hit some shots I never knew I had in me with it - working best from 7i down to start with but the shots with these clubs: WOW - amazing feel, and amazing natural distance control. Gerry’s advice that the clubhead should be treated as the slowest thing in the swing (something like that - say it better for me Gerry!?) is an awesome revelation for an over-accelerator like me.
Admittedly, I am occasionally very steep with long clubs so a bit inconsistent with these but some great shots. Working on discipline…
It beats good driving + the fats (all that wrongheaded right arm driving)!
It felt like I’d never hit a top class wedge/7i etc again so I’m pretty delighted. Putting distance control also much improved with the above ideas. Scoring clubs…
Unfortunately, the weather in Ireland is putting a hold on proper practice or playing (entire country flooded, incredibly windy, worst weather in about 15 years. Seriously.) so I’ve only had nine ‘fun’ holes to practice my new skills so far…c’mon the sunshine.
‘A golfer from the ground up is going from bigger parts to smaller parts – from hips/trunk/shoulders, arms to club and finally clubhead.’
“Mandrin. Can you go into this statement a little more, it’s kind of vague and I’m trying to figure out if your equations are based on it being true.”
BomGolf, I will give it a try. But I like to emphasize that I am not modeling a golf swing. The issue was explaining how angular momentum behaves in a golf swing.
The statement is simply saying that any golfer consists of heavy proximal parts and lighter distal parts. It does not refer to the golf swing. If you swing from the bottom up than the angular momentum passes from the heavier to the lighter parts on its way to the clubhead. The latter process is referred to as kinetic chain action. For some it has become like the holy gospel. I don’t feel that way. It is just one typical approach. An arms swing with the body used as stable platform is another approach.
" I’m not sold on the idea that movement starts from the ground, I think the ground receives movement through the feet and then multiplies it."
When you start bottom-up you will feel the forces acting through your feet. If however going top down, an arm/hands swinger, you likely feel it less, but ground forces are definitely equally present.
The ground action forces exerted by the golfer are exactly duplicated by the ground reaction forces. Newton’s third law. There is hence no multiplication effect.
Even if you think to swing primarily with the arms you would not go anywhere with your swing without adequate ground reaction forces to keep you solidly anchored to the ground.
" On a very basic level the arms leave the body which has nothing to do with the ground yet their actions will affect the speed of the clubhead."
You are mistaken that arm movement has nothing to do with the ground. Whenever any part of the body has a linear/angular acceleration it will generate an associated linear/ rotational ground force. We are perhaps not much very aware of this happening but if you were floating in space you would definitely know.
“Your model kind of makes sense if you were just assessing body rotational speed, and how to max that out, but even then a single axis of rotation is inaccurate imo.”
My post is mainly an effort to clean up the existing generalized confusion with regard to angular momentum. It is in no way an effort to model the golf swing.
" Then there are the subtle timing issues of when and where to accelerate in order to coordinate the opposing journeys of the body and arms/hands/club. I sometimes think that proving these ideas are games within games, kind of like fantasy football. They’re fun and can definitely be useful, but the more precisely they try to nail it all down and define it, the further they get from the truth of it all. But then again, I’m not a scientist!
A golf swing is indeed not some intricate scientific operation needing a science education. Our brains are so much more superior to any computer. It is, when some basics are adhered to, imo primarily a matter of feel. And it is fun that way. Let’s hope it will never be anything else.
Thanks for the thoughts, Mandrin, It’s definitely interesting stuff- and fair point that your post was originally about angular momentum. Though I would add that it’s application to the golf swing is the ultimate point here, so how, if, when, or why it occurs is important. And if the model doesn’t accurately represent the golf swing then how can it’s conclusions be applied to it? That was one of the points I was getting at in my post, and specifically re: the single axis of rotation, and the arms moving off the body.
I’ll just go with some thoughts as I’m no good at doing all the quoting stuff. It’s important to be exact, I think, when it comes to these things and I don’t mean to be picky I just dig into my thoughts on the swing in great detail in my own way. Saying that momentum moves from the heavier parts to lighter parts isn’t precise imo. Our feet are smaller than our backs, our calves are smaller than our hamstrings. The big parts are in the middle, not on the ground, this is an important point. If we move from the ground up we don’t just go from heavier to lighter, we go from light to heavy to light. This is important when we’re trying to find the actual origin of movement. We’re not at rest when standing up. Regardless of how balanced we feel we’re not resting until we’re lying down with our centre of gravity as close to the ground as it can be. With that as a basis of thought, it’s reasonable to argue that one of the main goals while in motion is to protect the centre of gravity- so maybe moving the COG causes propulsion in whatever form? Once we move, it will be altered and our body adjusts to protect it. The legs and feet will move to stay under it, it’s not a natural act to undermine the COG. I didn’t say that the ground forces weren’t present, my point was how they are arrived at. I think the feet may be receiving the motion and then using their grip on the ground to multiply it back up and out. So it doesn’t ‘start’ from the ground. I didn’t say that arm power had nothing to do with the ground in the golf swing, I was referring to arm motion- your arms can move without the ground, and if they do the will alter the bigger picture and must be taken into account. It may have been Gerry that said it, I can’t remember but it was a good description: if we were falling from an airplane we could have a fist fight and the blows would hurt.
It’s interesting stuff and I appreciate your input. A lot of the scientific aspects are new ground to me, so it makes for good thinking…
Cheers,
B
You are raising quickly several points all not directly related to conservation of angular momentum. You are like a cowboy shooting quickly form the hips in several directions at once.
Your point about cog, for instance, is closely related to the central theme in gravity golf. The very strong innate mechanism of our brains do everything it can to remain balanced.
If you are not aware of gravity golf I would suggest that you get David Lee’s book as it seems close to your preoccupations about the basic motivation for locomotion in the swing.
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Oh no!! I never thought I’d see that face again… great stuff… someone should have Mrs Magel as their avatar… it’s only right