We can agree that weight shift is irrelevant to power generation (with obvious exclusion of alignment issues.)
There are many muscles in the legs all with their particular functions. I cannot tell you which (and be sure to include the glutes) do turn the hips but I know they are down there.
You can turn your hips can't you? And you do not have to turn them fast to produce momentum. Do muscles muscles other than those in the legs cause your hips to turn?
Do you understand that you cannot turn your hips with muscles in the upper body? Well at least not in the directions that golf downstrokes require.
We can agree that weight shift is irrelevant to power generation (with obvious exclusion of alignment issues.)
There are many muscles in the legs all with their particular functions. I cannot tell you which (and be sure to include the glutes) do turn the hips but I know they are down there.
You can turn your hips can't you? And you do not have to turn them fast to produce momentum. Do muscles muscles other than those in the legs cause your hips to turn?
Do you understand that you cannot turn your hips with muscles in the upper body? Well at least not in the directions that golf downstrokes require.
Golfie
Add the hamstrings for rotation along with the glutes which as I understand it don't belong to the lower body/leg grouping. Also the oblique's play a role as well.
It is not clear to me which muscles cause which movement since I have conflicting data.
Again I will go back to my premise, the lower body amplifies the power of the upper body. You can't swing the golf club with only lower body movement, you can however swing the golf club without lower body movement (e.g. sitting on chair and hitting the golf ball).
Have you bought into any of Jack Kuykendall's notions. Jack hits balls from a stool, hits them quite well. Unfortunately he sits on a swivel seat and rotates 45 degrees on BS and through 90 degrees on DS - powering from the legs. Pure junk if you have.
How far can you hit a ball while seated? Anywhere close to full distance? If so you have an amazingly strong torso and have at it.
If your answer is 200yds. I regret to inform you that in order to move that ball out there 300 you need to find not 50% more power but 125% more power. You would only find this kind of muscle mass in the legs. This is not amplification . This is the real deal.
Muscles above the hips do not turn the hips. period. Think the twist. Equal and opposite reactions etc...
What happens in the golf swing is the hips rotation drive everything else. If you want add some torso firing, left shoulder effort or anything else into moving your golfers flail, have at it and enjoy the struggle.
Can you show us the formula that you used to come up with a 125% more power to move a golf ball from 200 to 300 yards??? Under normal math conditions, the number should be 150%!!!
I have seen one study conclude that the body only contributes 4.6% clubhead speed and 8.9% Power to the golf swing....with those numbers I would have to come to the conclusion that the body really makes a minimal contribution to the distance the golf ball travels.
Go to chapter 9 of TGM
Quotes from 9.1
ZONE #1 includes all the elements of Body movement and balance, and defines the geometrical alignments and relationships of the Body Components.
“The Pivot involves twisting the body and shifting the weight during the Stroke so as to maintain balance, a motionless head and any required tilt of the torso.
Quotes from 9.2
ZONE #2 adds the Arms and the Club to the circular motion of the Pivot just for generation of Clubhead Power (10-19-0). Zone #2 includes all the elements of the Force and Motion of the Arms and Club action—the Power Package—strictly the development of Clubhead Power rather Ball manipulation.
Can you show us the formula that you used to come up with a 125% more power to move a golf ball from 200 to 300 yards??? Under normal math conditions, the number should be 150%!!!
I have seen one study conclude that the body only contributes 4.6% clubhead speed and 8.9% Power to the golf swing....with those numbers I would have to come to the conclusion that the body really makes a minimal contribution to the distance the golf ball travels...
then why do we all bother to turn our hips?...hmmm, 250 yds.*1.089=272.25 yds...ah yes, now i remember, greed! \/
Can you show us the formula that you used to come up with a 125% more power to move a golf ball from 200 to 300 yards??? Under normal math conditions, the number should be 150%!!!
I have seen one study conclude that the body only contributes 4.6% clubhead speed and 8.9% Power to the golf swing....with those numbers I would have to come to the conclusion that the body really makes a minimal contribution to the distance the golf ball travels.
Go to chapter 9 of TGM
Quotes from 9.1
ZONE #1 includes all the elements of Body movement and balance, and defines the geometrical alignments and relationships of the Body Components.
“The Pivot involves twisting the body and shifting the weight during the Stroke so as to maintain balance, a motionless head and any required tilt of the torso.
Quotes from 9.2
ZONE #2 adds the Arms and the Club to the circular motion of the Pivot just for generation of Clubhead Power (10-19-0). Zone #2 includes all the elements of the Force and Motion of the Arms and Club action—the Power Package—strictly the development of Clubhead Power rather Ball manipulation.
Quotes to ponder!!!
DG
DG,
Glad you could join us. I assumed that most would have tuned out this discussion.
In order to adequately address your question, we’ll have to introduce another physics term: Work is what you get when a power source (e.g. muscles) operates over a period of time.
Power * Time = Work
In terms of what this means in terms of velocity of the clubhead, you can use this formula:
Work = Kinetic energy (KE) = 1/2mv*v (1/2 mass times velocity squared)
So let's say that the 200 yds swing had a clubhead speed of 100 mph (not true but bear with me - just keeping it simple) and the 300yd drive had a clubhead speed of 150 mph.
This means that the differential in work as expressed as a % increase to go from 200 yds to 300 yds is:
(150*150 - 100*100)/(100*100) = 1.25 or as I said above 125%.
Stated in another way - and ignoring the units and absolute values - the 300yd swing requires 2.25 times the power source. This is actually at a minimum as there is a second factor here - namely that the more muscles you recruit (thereby increasing your rotor motor horsepower), the sooner the swing is over. Therefore you need even more muscle to do sufficient work in the shortened timeframe.
Re: the very low % ascribed to body power in studies you mentioned. Please provide references if you could. One needs to scrutinize these carefully as often they make statements like" well the hips can only more 2 mph" and do not understand anything about angular motion. Jorgenson in "The Physics of Golf" determines that only the legs contain enough muscle mass to power the golf swing.
Glad you could join us. I assumed that most would have tuned out this discussion.
In order to adequately address your question, we’ll have to introduce another physics term: Work is what you get when a power source (e.g. muscles) operates over a period of time.
Power * Time = Work
In terms of what this means in terms of velocity of the clubhead, you can use this formula:
Work = Kinetic energy (KE) = 1/2mv*v (1/2 mass times velocity squared)
So let's say that the 200 yds swing had a clubhead speed of 100 mph (not true but bear with me - just keeping it simple) and the 300yd drive had a clubhead speed of 150 mph.
This means that the differential in work as expressed as a % increase to go from 200 yds to 300 yds is:
(150*150 - 100*100)/(100*100) = 1.25 or as I said above 125%.
Stated in another way - and ignoring the units and absolute values - the 300yd swing requires 2.25 times the power source. This is actually at a minimum as there is a second factor here - namely that the more muscles you recruit (thereby increasing your rotor motor horsepower), the sooner the swing is over. Therefore you need even more muscle to do sufficient work in the shortened timeframe.
Re: the very low % ascribed to body power in studies you mentioned. Please provide references if you could. One needs to scrutinize these carefully as often they make statements like" well the hips can only more 2 mph" and do not understand anything about angular motion. Jorgenson in "The Physics of Golf" determines that only the legs contain enough muscle mass to power the golf swing.
Golfie
GMcG,
doesn't the above calculation make the assumption that all the difference in KE from 100 to 150 mph is transferred to the ball?...i don't think a 150 mph impact speed clubhead slows to 100 mph during impact...anyway, as i've said before i think it is the equation F=ma that answers the distance question and not velocity but acceleration at impact that makes the most difference (assuming equal clubs and equally good ball contact) and that is why slow easy swings with late release and therefore high late acceleration can hit the ball as far or farther than some really hard swings.
1. I don't subscribe to JK. Have read only a little of his stuff and ......
2. You seem to rely on Jorgenson
Quote:
Jorgenson in "The Physics of Golf" determines that only the legs contain enough muscle mass to power the golf swing.
Interesting to note Jorgenson did a paper exercise to come up with most of his conclusions. Actually regarding the power, he used the formula and applied it to the golf swing. Based on a professional golfer generates 2 hp (not sure where this number came from) he deduced that it require 32 pounds of muscles or 1/8 horsepower per pound and muscles must be used in pair, so 32 lbs. Since the arms and shoulders don't have 32 lbs he reasoned that other muscles must be used. Those were the legs, buttock, back aand abdomen. He considered these to be the lower body muscle group.
The hips are key to momentum transfer. If hip action is initiated it is with the buttock's muscles. The leg muscles (hamstrings) can push and pull the hips.
I find that in the introduction by Jorgenson, his description of Chapter 3, "... explains how the golf swing compares to theaction of a bullwhip, how the large muscles of the lower body, although they are not connected to the arms are used to enhance the speed of the golf club, how the pull of the shoulder on the arm works in the golf swing and who we find that the golfer does not swing about a quiet center in the downswing."
I find his choice of words, 'enhance' to support the position I have held and what I have said. I stated earlier that the lower body 'amplifies' allowing greater power.
As for the hip movement, I subscribe to this being either the first action in the down stroke, or as the golfer is about to complete the back stroke (for those who want a reference 12-3-0 section 6 #24).
Thanks for the follow-up with your equation....looks good!
The source of my study on clubhead speed and power comes from Mark Evershed's book....The Golf Solution....
Here is an excerpt from that study....
If you still believe that the body creates the speed and power in your golf swing, and pervious pages have not yet changed your mind, You can stilll prove it to yourself by following the directions below. You will need a device to measure your clubhead speed.
S1 After warming up, measure the clubhead speed of your driver using your normal swing and averaging the three highest readings. This figure respresents 100% of your speed and energy potential.
S2 With your feet together, swing and measure your clubhead speed. (This eliminates the contribution of the body).
S3 From your knees, swing your driver and again measure your clubhead speed (This eliminates the body and the sequence (vertical drop).
S4 Finally, while still on your knees, swing the club with your hands, wrists, and forearms stiff or immobilized. The clubshaft should point at the middle of your chest during the entire swing. (This eliminates the body, vertical drop and hands, and measures only the contribution of the arm swing).
Here are Mark Eversheds results....someone who is accomplished golfer....
Quiet Body Clubhead velocity Contribution 4.6%
Clubhead Power Contribution 8.9%
Educated Hands Clubhead velocity Contribution 60.0%
Clubhead Power Contribution 58.9%
On-Plane Arms Clubhead velocity Contribution 19.1%
Clubhead Power Contribution 3.6%
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