mandarin » Fri Nov 20, 2009 11:27 am
You are very strong on mentioning, in a variety of ways, that the only thing that counts is the scientific truth, no bullshitting, no ego trips, just the simple truth as dictated by physics since the beginning of time. Hence I am sure that you will appreciate it that I have some questions regarding this truth as exposed in your book - ‘The Hogan Manual of Human Performance’.
I find your opening paragraph interesting, it offers insight into your state of mind when you wrote your post, doesn’t it? What’s your background and what golfing cult do you represent?
What you have written is not a correct interpretation of what I have said, not by a very long stretch of the imagination. I have often stated that the accepted and proven laws of science are indeed immutable and I will use them whenever and wherever possible. I have also used many other areas of science that are not taken from Physics. I have also made it clear to all and sundry, on countless occasions, that I have never been trained formally in any field of science and I have never pretended otherwise. I have seen fit to visit the various sciences involved in my work to seek out truth where there has previously only ever been speculation and theory.
page 15…
a)“As every engineer knows, if you pass energy along a transmission chain, you will lose some of it at every coupling or joint. Now in purely mechanical terms, the joints of the human body are extremely inefficient at transmitting energy. As a result, as much as 90 per cent of any energy you generate by a movement of the legs or hips would be lost by the time it reached the club.”
If muscles are taut in midsection, would you still maintain this figure of 90 per cent?
In the real world one is not allowed to use the hypothetical or the presumed. Stick to the facts.
Go back and read it in the context in which it was written. I invite anyone who reads this post to do the following; go to the top of your backswing and use legs and hips ONLY to accelerate the downswing. No, you cannot swing your arms, straighten your right arm, hit with hands, not even change/ alter the relationship between the arms and the torso, as they were at the top, you MUST create all acceleration with legs and hips only.
Read in context it matters little if muscles are ‘taut in midsection’ or not, does it? Without movement that is independent of legs and hips you cannot even get the clubhead to the ground, can you ?
At the time that this book was written, the most predominant basis of teaching was that legs and hips powered the entire golf swing.
Examine the performances of a good front (direct) wheel drive car and a good rear wheel drive car. Because of the number of couplings and joints needed to get the power from the motor to the rear wheels, the rear wheel drive will proportionally lose far greater energy values into the ground then the front wheel (direct) drive will.
The human skeletal system has many more joints and couplings than a rear wheel drive car has, there are 33 vertebra in the spine alone, the vast majority of which offer some degree of flex/ rotation.
b) “In the golf swing, the angular momentum you generate with your upper torso at the start of the swing is transferred through shoulders, arms and clubshaft to momentum at the clubhead.”
That is absolutely correct, in the context in which it was written. When you write a book, or prepare any form of instructional material, the real art lies in absolute simplicity. The key is to write in such a manner that all who may wish to read it can understand it, on first sight.
A complete description would have started with the toes, working through the feet, the ankles, the knees, the hips, the spine and torso, the arms, the hands and then the clubshaft out to clubhead. I, as the writer, saw no value in that for my purposes, at the time.
Did anyone else interpret it as creating angular momentum in the backswing? No one else has to my knowledge.
c) “Contrary to what most golfers believe, you cannot generate power in the downswing. The downswing merely releases and transmits the power that was stored when you turned your torso in the backswing. Technically, the secret of the golf swing is to lose as little as possible of this power in the transfer from torso to clubhead, which is why I speak of the conservation of angular momentum.“
Again, read it in the context in which it was written and the continuing theme throughout the chapter and the book. In the backswing and at the top of the downswing, the critical need is for the elimination of all slack from the entire system, as far as it is possible to do so. No, you are not winding up any spring like coils and creating recoils because no form of elasticity exists in the human skeletal body.
Nor can you create or use any form of useful, controllable POWER in the downswing other than TORQUE, twisting power. If you use, or attempt to use, any form of acceleration from the top, or during the early downswing, you run into direct conflict with Newton’s Third Law of Motion…To create motion you must apply a force against a resistance that is both equal and opposite. If you accelerate the clubhead by using the shaft as a lever, you MUST decelerate the opposite end of the lever, the butt, which is held in your hands. If the hands decelerate, so too MUST the body, it has no option. I doubt that we need to go into what happens when the body slows and stops long before the clubhead reaches the ball, do we?
There is another reason why you cannot generate POWER in the downswing by any means other than by turning and that’s because the human system of locomotion is leverage. And Leverage comes in three classes. Since the effort (muscular) is located approximate to the joint and the load to be shifted is located at the opposite extremity, this is the wrong Lever Class though which to multiply FORCE. The human system is Class Three, which is a speed multiplier, to generate power one needs the load to be sited approximate to the fulcrum, with the EFFORT applied at the opposite extremity.
That seems to eliminate the creation of any useful, controllable form of POWER in the downswing, other than the twisting force, Torque.
The power generated in a car’s engine arrives at the axle and turns it. If one had tiny little wheels fitted tightly around the ends of the axle that were about six inches in diameter, the car would not be going anywhere, very quickly. However fit some 19” wheels and, if there is enough power produced by the engine, that car will become a flier. Won’t it! Damn Radial Acceleration again!
Same applies in the golf swing. The central turning torso does not have to turn all that fast to create 100mph at the clubhead.
Yes one can assume that b) refers to angular momentum generated during the downswing. That’s hardly Rhodes Scholar levels.
However c) implies that it is generated in the backswing and that it is the secret of golf to lose as little as possible of it in the downswing.
You are presuming, yet again, this time that something is “implied” . Whatever I have written down that you wish to criticize, by all means do so. I’m certainly not in the least interested in what you, personally, might feel it may imply.
Kindly point out where I have said that you generate angular momentum in the backswing. It seems that, in your opinion, it’s implied
but where is it stated.
Accordingly your following paragraph is not worthy of the time that it took to write.
…
d) “The back swing is a purely preparatory movement. Its purpose is to get the club, the arms , the torso and, most important of all, the hands to move into the correct position from which to begin the downswing.”
I see, we are back to c) again and what you presume that it implies. If you are white, male, over 30 and own a white shirt and a murder suspect was described as being white, male, over 30 and wearing a white shirt, does that imply that you are the wanted man? What may be implied is not permissible in court rooms, debates, research findings etc. Thankfully! Nor is it acceptable here.
What you have written in this post might well imply that you have various shortcomings but that doesn’t necessarily mean that you have. Does it?
The backswing is indeed a preparatory movement. Just after this book was published, Chanel Nine, Sydney Australia sent their sports interview team to where I lived to do a Sunday Sports Special, led by Mike Maher. During the course of events on the evening of their arrival, and after the mandatory few beers, Mike kept at me over the critical importance of the backswing until I finally got pissed off enough to state that I would bet him that I could hit a ball 275-280 yards without a backswing. No tricks, no backswing.
Next day after I thought that all audio and filming was finished, he reminded me of the bet and called me on it. And the cameras were still rolling. I addressed a teed ball with my driver. I then looped the clubhead up over the teed ball and placed it in front of it. I then swung the clubhead to the left, looped clubhead and shaft over my head, dropped the club down behind my back and continued on, turning and swinging through the ball. No backswing. The crew measured it, 280 yards. Maher bet me I couldn’t do it again and I did, a bit further. That was on tape and was shown on Chanel Nine Sports Sunday. More than a million people saw that.
That’s how much I think of backswings!
The context of the full meaning in the book was that the backswing prepares for the downswing, not by creating power or storing energy, but by ELIMINATING SLACK from the mechanical system. You get to the top in a manner that allows your to lock and then turn.
To make it easier for you, personally, to understand, allow me to put it this way. Suppose you have a spoked wheel, car wheel, wagon wheel, whatever and, initially, it it is fitted with flexible spokes that are also loose fitted to the rim and the axle. Any chance of that performing at any great heights? Didn’t think so! You then get an identical wheel that is fixed rigidly to axle and rim, and with inflexible spokes (levers) isn’t that what you find on Ferrari and the like?
Then you tell me that something appears to be a contradiction. Is a contradiction or is it not a contradiction, if you don’t know, don’t raise it!
Finally you claim that there is ambiguity because I refer to power and angular momentum as if they are the same thing, but I didn’t. If angular momentum is not the result of a twisting force then what is it? At no time in my life have I ever suggested that angular momentum is or could be a force, but I’m happy with the fact that it is indeed a consequence of an applied force.
You did achieve something though. From the many tens of thousands, more probably, hundreds of thousands, who have bought or borrowed that book, including all manner of professional scientists and those educated in or associated with sciences, YOU are, to my knowledge, the only one ever to criticize any aspect of it, other than one drone who felt that it was too ‘simplistic’.
You may be an extraordinary genius who can see what countless tens of thousands have never seen or commented on.
Alternately, you may well be the only yet who has not been able to see and understand what a vast mass of others have accepted and used. What would that make you?
Cheers
Gerry.
It’s all about training the correct motion - which I am sure you would be proud of, even though it is done in a slightly different way.