Weight shift

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Ben Hogan's idea of a full golf swing being analogous to a side-throw ball throwing action and an optimum model for understanding weight shift in a full golf swing fits the school of thinking where the power is thought to be a mainly a matter of trail side action. However at one time it was thought to be exclusively a lead side affair like, for example Prof Jorgensen, and it was advised to forget the trail side almost as being a nuisance. ;)

Mandrin, you may have already stated this but which of these two ideas above do you feel works best?
 

JeffM

New member
Mandrin - you stated "Ben Hogan's idea of a full golf swing being analogous to a side-throw ball throwing action and an optimum model for understanding weight shift in a full golf swing fits the school of thinking where the power is thought to be a mainly a matter of trail side action."

What do you mean when you state that Ben Hogan's model implies that power is due to trail side action?

Are you implying that Hogan's model is a push-model rather than a pull-model?

I don't think of the golf swing in that way.

I think that a simplistic way of thinking of a full golf swing is the double pendulum swing action model.

See - http://www.tutelman.com/golfclubs/DesignNotes/swing1.php?ref=golfcoast

Power is generated at the central hinge point via the central torque generator. Jorgensen states that no active forearm/wrist power is needed to activate the peripheral hinge point, and that active wrist unhinging doesn't significantly increase clubhead speed in his experiments.

The double pendulum swing action model is simplistic because it doesn't discuss how the central torque generator operates at the central hinge point. For example, we know that the central hinge point is moving lateerally towards the target in the early downswing and that this must help increase swing power. I also think that the muscles responsible for torque generation at the central hinge point are the large muscles of the body (mainly thighs, lower/mid torso muscles) and that they cause the torso to shift-rotate towards the target at the start of the downswing. This shift-rotation in the early downswing can be easily seen in this photo of Ben Hogan's early downswing action.

See - http://perfectgolfswingreview.net/Hogan-DScomposite.jpg

Looking at the photograph, one can infer which body actions are probably generating the power.

It is mainly the lower body (thighs and lower torso) which causes the right hip to rotate forward into a squaring-position while the entire pelvis is shifting to the left. There is presumably an active uncoiling action operating through the central torso (abdominal oblique muscles and chest cage intercostal muscles and shoulder girdle muscles) and they cause the shoulders to turn in the earliest phase of the downwsing. While the lower/central torso is shift-rotating to the left and producing a torsional force at the central hinge point, the right upper arm is simultaneously being pulled rapidly towards the torso which causes the right elbow to drop rapidly towards the right hip area. I don't believe that this upper body action (operating through the shoulder girdle muscles on the right upper arm) increases swing power via the torque forces operating at the central hinge point. I think that the upper body action is needed to keep the right side of the body moving in synchronised unity with the rest of the body, so that the entire torso works as a single cohesive unit.

I see the shift-rotation movement of the lower torso, and the active uncoiling action of the central torso, being a "pulling action" , which is responsible for torque generation at the central hinge point, and that the "pulling action" is complex because it it involves a shift of the torso as well as a rotation of the torso while the spinal axis is tilted to the right (torso is swivelling is space around a rightwards tilted axis while the central torque generator is operant). When thinking of this model, I don't think of the model as having a lead side action and a trailing side action. The model implies that the lead and trail side operate as a single cohesive unit.

Jeff.
 
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Ben Hogan's idea of a full golf swing being analogous to a side-throw ball throwing action and an optimum model for understanding weight shift in a full golf swing fits the school of thinking where the power is thought to be a mainly a matter of trail side action. However at one time it was thought to be exclusively a lead side affair like, for example Prof Jorgensen, and it was advised to forget the trail side almost as being a nuisance. ;)

Mandrin, you may have already stated this but which of these two ideas above do you feel works best?
Sonic_Doom

At one time left side dominance was the general accepted wisdom with only a few exceptions, e.g., Tommy Armour. Presently there is more frequently reference to right side actions such as skipping a stone or making a sidearm underhand throw and less to left shoulder pull, as by Jorgensen, or throwing action of a frisbee. I don’t know which is better from a scientific point of view. There is perhaps a very general argument I can see in favor of lead side action and that is that pulling in front leads more readily to a stable repeatable motion at the periphery (clubhead) than a pushing effort from behind.

Let me just add a few more general observations inspired by your question.

People for ever want to use the logic of yes and no, black and white, separating things, cataloging concepts. Once something has gotten a distinct label it almost takes on a life of itself and becomes often source for vigorous debate. Golf has lots of this labeling - swinging vs hitting, pulling vs pushing, body vs arms, right vs left side, quick vs heavy hit, mind vs matter, etc..

Is there something as ONE scientifically optimum swing for all? Definitely for a robot golfer but quite likely not for a real golfer where scientific principles play a role but many more variables are introduced into the equation based on the golfer himself. However I believe that a small number of clearly defined concepts are important. Several such concepts as plane, centrifugal force, kinetic chain, 'power' accumulators, etc., constitute a healthy foundation on which a more individual stroke pattern can be built, but I don’t see one optimum model.

One has to be careful even with the opinions of scientists, when discussing golf. :D Well known and very respected scientists such as Cochran et al, and Jorgensen derived that the energy of the swing, from a power viewpoint, comes in great measure from muscles other than those of the arms and shoulders, i.e., hence rather from legs, thighs and back. However their reasoning leading to this conclusion is wrong. It is based on the power produced only by the muscles and it ignored the considerable power generated by the inertial joint forces. Both Cochran and Jorgensen seemingly were unaware of this very significant contribution. Their conclusion has been accepted without questioning by many, such as, for instance, David Tutelman on his interesting website.

Both Jorgensen and Cochran et al were convinced that a powerful golf swing to be mainly a lower body powered affair. This probably stimulated and polarized the long standing debate between those who feel that power comes form the body rather than from the arms or vice versa. The golf swing still might be mainly an affair of the lower body muscles but the scientific arguments used by Jorgensen and Cochran to support this view are not as conclusive anymore. Therefore those who believe that the arms play a major role producing power in the golf swing have a little more leeway for there arguments and hence to keep the debate alive. ;)
 

JeffM

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Mandrin

A simple question. Mentally picture a 180 lbs golfer who has considerable mid-torso weight eg. Ken Perry. How can the idea that the "left arm pulls the swing" be biomechanically plausible? Which muscles in the left arm and left shoulder girdle have the muscle power to pull the golfer's weight across from the right side to the left side while at the same time producing clubhead speeds of >100mph? If one argues that the torso muscle react in such a way that the torso responds to the "pulling action of the left arm" and the torso simultaneously moves in perfect harmony with the left side of the body, then it is equivalent to stating that the TOTAL body powers the golf swing (which is my position). I previously described how Hogan's downswing concept gives one an idea as to how the swing is powered (lower body shift-rotates laterally first + torsional rotation of the mid-upper torso). However, I also believe that the left side must pulling at exactly the same time, so that the the golfer's "swing form" is biomechanically coherent and biomechanically maximally efficient.

Jeff.
 
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Brian Manzella

Administrator
GEEZ!!!

Back in the early 80's they stuck needles in all the top PGA TOUR players and EVERYONE was within 4% of 50-50 in muscle activity!!!!!!!!!!!!!

sigh.:eek:
 
Mandrin

A simple question. Mentally picture a 180 lbs golfer who has considerable mid-torso weight eg. Ken Perry. How can the idea that the "left arm pulls the swing" be biomechanically plausible? Which muscles in the left arm and left shoulder girdle have the muscle power to pull the golfer's weight across from the right side to the left side while at the same time producing clubhead speeds of >100mph? If one argues that the torso muscle react in such a way that the torso responds to the "pulling action of the left arm" and the torso simultaneously moves in perfect harmony with the left side of the body, then it is equivalent to stating that the TOTAL body powers the golf swing (which is my position). I previously described how Hogan's downswing concept gives one an idea as to how the swing is powered (lower body shift-rotates laterally first + torsional rotation of the mid-upper torso). However, I also believe that the left side must pulling at exactly the same time, so that the the golfer's "swing form" is biomechanically coherent and biomechanically maximally efficient.

Jeff.
Jeff,

You ask Brian when he demonstrates throwing his frisbee with his left arm how he gets his impressive power. ;) Don’t strangle yourself trying to find out which muscle does what, there are quite a few and by thinking too much about them you might occur paralyze by analysis. :D

sw_hit.jpg


The basic unit in the golf swing is the triangle which one folding member, the trail arm, shown above. This triangle has a pivot point which can move a bit 3D but is rather stationary in space. Moreover the triangle has a very useful Checkrein effect. We assume for simplicity that the central pivot is stable since its potential effect on the swing speed is only in the order of magnitude of about 5 %. We also assume for simplicity that the shoulders form one solid segment. Everything from the feet up to the shoulders contributes in its own particular way to the central torque acting through the shoulders and indicated by the torque around B. There can be a torque at each shoulder joint A and C. The straightening action of the trail arm is equivalent to a torque around the central pivot and a torque acting directly on the shaft.

shoulders.jpg


If the mind is focussed on the lead side there is a more a feeling of pulling. If the focus is more on the trail side lead, especially when there is active pistoning, one feels like pushing. It might feel very different but the Checkrein action is equalizing things. Pushing and pushing in a mathematical model are very similar, there is however a huge feel difference for us human golfers.

Hitters and swingers, pullers and pushers, they have no choice but to use the same muscles between feet and shoulders. The main difference is in the focus of our mind. I found it interesting some time ago on another forum not to be mentioned here where the leader posted video of himself demonstrating swinging and hitting. A very lengthy discussion ensued since it was seemingly very difficult to detect any difference. :D

I am quite convinced that in a full fledged golf swing swinging and hitting have very similar action with regard to the the various muscles contributing to the golf swing. In addition the Checkein effect makes pushing and pulling actions to be acting like inseparable twins, therefore swingers and hitters are also very close family. :p
 
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Great insights, Mandrin. The Tutelman site is pretty cool. That Trebuchet animation is an awesome visual!
 
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JeffM

New member
Mandrin

I don't understand your model.

In terms of powering the golf swing, I am thinking of torque forces operant centrally at B. I can understand a golfer having a "feeling" of pushing in the trail arm and a "feeling" of pulling in the lead arm, but I don't understand what those "feelings" mean in terms of swing power. In the double pendulum swing action model, the two arms are treated as a single unitary structure, which is passive, like a mechanical lever, and that responds to centrifugal forces set into play by torque forces operant at the central hinge point B. I don't understand what your model is designed to show.

Jeff.
 
Mac says that there is no such thing as hitting

I take it that Mac isn't the only one.....and I think I agree man....

I was thinking....

Even if you're Thrusting with the right arm thru Impact......

Your torso invariably it IS going to be unwinding at the same time (no matter who the heck you are)............

So if we can say that every golfer is unwinding (even the so-called "Hitters" and anyone who Pushes at all with the right arm)........how is this not Pulling/Swinging?

The only thing I can really think of to shut myself down is that YOU (actively) stop pivoting at some point.....I think it continues thru Impact tho no?
 
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I take it that Mac isn't the only one.....and I think I agree man....

I was thinking....

Even if you're Thrusting with the right arm thru Impact......

Your torso invariably it IS going to be unwinding at the same time (no matter who the heck you are)............

So if we can say that every golfer is unwinding (even the so-called "Hitters" and anyone who Pushes at all with the right arm)........how is this not Pulling/Swinging?

The only thing I can really think of to shut myself down is that YOU (actively) stop pivoting at some point.....I think it continues thru Impact tho no?

right arm participation determines hitting/swining....not pivot. The pivot is always 'pulling'.
 

Brian Manzella

Administrator
Nobody is saying that the right arm isn't:

FEELING SOMETHING DIFFERENT.

IN DIFFERENT ALIGNMENTS.

But, just like RFT, Hitting is sold as something "revolutionary."

I teach different RIGHT ARM FEEL and RIGHT ARM ALIGNMENTS to everyone that needs 'em.

But, Leo (and others) words are important. And the word HITTING doesn't work for many.

Also, PURE HITTING is something that is discussed, but in many people's opinion, never done at a Tour level.
 

Brian Manzella

Administrator
PURE.

Aaron Zick did that Math.

Pure swinging would result in about 85% of your clubhead speed potential.

Most TOUR players use way more than 85%, so that are all MIXERS!
 
right arm participation determines hitting/swining....not pivot. The pivot is always 'pulling'.

You are right Leo.

But if Swinging is pulling.....and Hitting is pushing.........

.....and the Pivot is always pulling......

....when people call a person a "Hitter" (flat-out)......

Does that make sense?

4B man.

....

And as for "pure" anything....I'd take "pure Swinging" over "pure Hitting" (if it's actually possible NOT to pull at all in a golf stroke) that's for sure.
 
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Mac says that there is no such thing as hitting and more than 4 power accumulaters and more then 4 pressure ponts.
His main complaint about THE BOOK is that is does not have a bibliography.

good point...

Chapter 7-19 TGM 7th Edition

"The correct Clubhead Lag Pressure "Feel" is a deadweight inertia-exactly like dragging a wet mop through Impact-constant Loading, constant direction"

Author "a" predating Homer...

"Golf rhythm is a delayed dragging feel of the clubhead..."

Chaper 7-14 TGM 7th Edition

"A Hula Hula flexibility allows the Hips and Shoulders to be independent ..."

Same Author "a" predating Homer...

"... we must be able to leave our shoulders behind; they have no direct torsional connection with the hips..."


TGM 7th edition 3-F-6
"All quick, jerky and wobbly motions are improper execution"

A different author "b" predating Homer

"There can be no quick jerky movements at any stage of the procedure"

... alot of similar phrases... he must have read both these authors... not plagiarism... just the original authors used all the best words in the first place!

But referencing them is good practice!

ANy guesses for authors "a" and "b"??? no prizes this time Armourall!!:D
 
-4- Counter balancing upper and lower body, com stable?

Another idea is that the upper and lower body in the downswing is simply doing a balancing act whereas the overall center of mass remains virtually in one spot. Someone starting the down swing with a vigorous lateral slide will likely move his upper body a bit backwards.

Let’s see what Toski and Flick have to say in “How to become a complete golfer”.

Because balance is so vital to the execution of a good golf shot, we feel this is the place to explode another myth – that of weight shift in the golf swing.
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Instead of a weight transfer, we believe there is a transfer or change of body position that creates the momentum of the club on the forward swing.
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In fact, we believe that the center of gravity of your body doesn’t change at all form address to impact.
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What you are confusing with weight on your left leg is really pressure as the leg bows toward the target.
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These few phrases above clearly explain their view on dynamic balance and weight shift. It agrees with those who teach more lateral motion in the down swing. When done with enthusiasm it leads to the once popular reverse C position, now thought of as not very healthy for the spine.

Thrusting the lead hip forward whilst keeping the head back, or even going more back, is indeed a motion with can be done quite vigorous, even more if we allow gravity to give us a little hand. This is illustrated in the Figures 1 and 2.
w_s_3.gif
As soon as we are relaxing the support of the trail leg there is a torque generated around the left hip with will help the rotation around a horizontal axis. It might feel like a fall into the lead hip joint, or a sliding sitting motion into the left side.

This motion comes rather abruptly to a stop and automatically changes into a rotation about an approx. vertical axis. The 'sudden' stop is a good thing in a kinetic chain as it promotes effcient transfer of kinetic energy.
w_s_4.gif
]​
The down swing can be conveniently treated anlyzing the vector sum of rotations about a horizontal and vertical/spine axis. The resulting swing plane it generates depends on the emphasis given to either one, which together determine the resultant axis of rotation and thus associated swing plane.

However it can be argued that a feel emphasis on the rotation about the horizontal axis in the downswing is to preferred as it helps to get the trail shoulder on the right path, or simply, in general, to get down on a proper inside path to the ball.
 
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Mandrin

I don't understand your model.

In terms of powering the golf swing, I am thinking of torque forces operant centrally at B. I can understand a golfer having a "feeling" of pushing in the trail arm and a "feeling" of pulling in the lead arm, but I don't understand what those "feelings" mean in terms of swing power. In the double pendulum swing action model, the two arms are treated as a single unitary structure, which is passive, like a mechanical lever, and that responds to centrifugal forces set into play by torque forces operant at the central hinge point B. I don't understand what your model is designed to show.

Jeff.
Jeff,

The double pendulum model is the simplest model one can imagine representing a golf swing. It is indeed remarkable that such a simple model can nevertheless tell us so much about the swing.

The inner segment of this model is an approximation of the triangular structure formed by arms and shoulders. A slightly more elaborate model should hence incorporate arms and shoulders. The triangle has a built-in constraint relation, the checkrein action, as joints C and E constitute a constraint for the motion of the two arm segments.

The work done by the central torque is acting on the club through both arm segments. The power flow from B to D/E comes about via the work done by the joint forces operating at joints A, C, D and E.

The model is trying to convey the idea that via the triangle, due to the constraint relations (checkrein effect), there is a very close relation between ‘pulling’ and ‘pushing’. Feeling wise however they are very different.

Checkrein:
- A branch rein connecting the driving rein of one horse of a span or pair with the bit of the other horse.
- A short rein looped over the check hook to prevent a horse from lowering his head.
 
mandrin, in your last two models the focus seems to be on the latteral motion of the hips and not so much on the rotational? In the 7th edition homer wanted the stoke pattern to be more of a shift from the top, or slide, and not so much rotational. yes it has to rotate back to square or very close to it but that is a lot less rotation then a tiger woods. what does your science say about homers slide rather then just trying to rotate your hips as far and as fast as you can? we know in kinetic energy that if the hips and shoulders are still rotating there has not been a full transfer of energy. so optimumly kinetic energy wise, they would be square at impact and allow the pendulum to not be comprimised. therefore maximizing the swing
 
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