Release
- Thread starter mandrin
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mandrin
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Why not ask your favorite boffin.
Bronco Billy
New member
Post Collision.......
Doesn't this Rolling If it Occurs at All Occurs AFTER the GolfBall is Impacted...... Nothing is Relevant after the Collision.... Have a Great Day....
Doesn't this Rolling If it Occurs at All Occurs AFTER the GolfBall is Impacted...... Nothing is Relevant after the Collision.... Have a Great Day....
Doesn't this Rolling If it Occurs at All Occurs AFTER the GolfBall is Impacted...... Nothing is Relevant after the Collision.... Have a Great Day....
Not necessarily, BB. Some players roll their arms clockwise on the backswing, so they must reverse the action on the downswing. This action is commonly taught by many instructors.
Why not ask your favorite boffin.
Actually I have two favorite boffins, which includes yourself, so what is your expert opinion?
Bronco Billy
New member
Lost Knowledge.....
Right.... I've Been Counter Rotating(TwistAwaying) For So Damn Long I Thought the Rest of the World also UpGraded..... I'll Have a Great Day with My Newly Found Old Obsolete Knowledge....
Right.... I've Been Counter Rotating(TwistAwaying) For So Damn Long I Thought the Rest of the World also UpGraded.....
I'll Have a Great Day with My Newly Found Old Obsolete Knowledge....
mandrin
New
Slowing down of the hands is not a choice, is not deliberate, but is forced upon the golfer. It is caused by the large negative torque exerted by the golf club on the arms when it is starting to release rapidly. The same mechanism operates equally for an Iron Byron. It is virtually impossible to not have this deceleration in a golf swing even if one tried very hard to avoid it on purpose. A typical velocity/acceleration profile for the hands till just past impact, applying constant effort, is shown in Figs1/2. Notice the deceleration prior to impact (blue).
However everyone can be the judge on this whilst comfortably viewing golf on TV at home. The magnificent Swing Vision video sequences shown of a Tiger Woods, a Vijay Singh, or any other pro, show always very clearly the same pattern. The arms/club comes down from the top as one unit. Then hands slow down considerably whilst the club starts rotating rapidly around them. Once past impact hands pick up speed again.
This phenomenon was unearthed already quite some time ago using high speed stroboscopic photographic techniques. Jorgensen’s ideas in “The Physics of Golf” are largely based on such a stroboscopic sequence of a real golfer’s swing to tweak and validate his mathematical model of the swing. It is also right up the sleeve of the theory of kinetic chains. The slowing down of the proximal core elements allows the distal elements to partake this energy and speed up as a consequence.
The golf club has two velocity components, one is the curvilinear speed of the center of mass and the other is the angular velocity of the club around the center of mass. A sound release allows these two to act as a solid cooperative team to obtain optimum clubhead speed AND impact alignment. Forcing the hands to accelerate through impact zone primes the linear speed but does not allow the angular speed component to quite fully develop, trying to release whilst receiving energy of arms slowing down.
The golfing world is populated with generations of chronic slicers. Having someone ‘SHOUT’ to continuously accelerate is not the best advice one can give to the average amateur, showing a profound lack of knowledge of the inner workings of a golf down stroke. It will for ever assure all golf instructors an assured income having to teach an even larger crowd of chronic slicers. Some others, more subtle, are equally engaged on this wrong track. Instead the emphasis should be not on accelerating through impact but on educating the feel of swinging the hands up to a point just past the ball and not on accelerating the hands through impact and beyond. It more readily stimulates the notion of retaining the angle as well as letting go.
A sound golf down stroke has basically two phases, an energy producing phase followed by a release phase. The release phase is one where emphasis should be primarily on obtaining proper club face alignment, not on power slugging the club through impact. Very much like Michael Jacobs’ teaching approach (post #98}. A little bit of freewheeling through the shot is not too bad. A golfer by the name of Bobby Jones did not do all too bad with it.
The only sound way to try to increase impact speed somewhat, close to impact, is not by accelerating the hands along the target line but by raising the swing center; hence by pulling on the handle, perpendicular to the target line. Perhaps not readily intuitively understood. Scientifically the reason is that with the clubhead close to impact the centripetal force is at its maximum and pulling inwards/upwards on the handle constitutes considerable work being done and hence ‘injecting’ very fast appreciable kinetic amount of energy into the club head.
However everyone can be the judge on this whilst comfortably viewing golf on TV at home. The magnificent Swing Vision video sequences shown of a Tiger Woods, a Vijay Singh, or any other pro, show always very clearly the same pattern. The arms/club comes down from the top as one unit. Then hands slow down considerably whilst the club starts rotating rapidly around them. Once past impact hands pick up speed again.
This phenomenon was unearthed already quite some time ago using high speed stroboscopic photographic techniques. Jorgensen’s ideas in “The Physics of Golf” are largely based on such a stroboscopic sequence of a real golfer’s swing to tweak and validate his mathematical model of the swing. It is also right up the sleeve of the theory of kinetic chains. The slowing down of the proximal core elements allows the distal elements to partake this energy and speed up as a consequence.
The golf club has two velocity components, one is the curvilinear speed of the center of mass and the other is the angular velocity of the club around the center of mass. A sound release allows these two to act as a solid cooperative team to obtain optimum clubhead speed AND impact alignment. Forcing the hands to accelerate through impact zone primes the linear speed but does not allow the angular speed component to quite fully develop, trying to release whilst receiving energy of arms slowing down.
The golfing world is populated with generations of chronic slicers. Having someone ‘SHOUT’ to continuously accelerate is not the best advice one can give to the average amateur, showing a profound lack of knowledge of the inner workings of a golf down stroke. It will for ever assure all golf instructors an assured income having to teach an even larger crowd of chronic slicers. Some others, more subtle, are equally engaged on this wrong track. Instead the emphasis should be not on accelerating through impact but on educating the feel of swinging the hands up to a point just past the ball and not on accelerating the hands through impact and beyond. It more readily stimulates the notion of retaining the angle as well as letting go.
A sound golf down stroke has basically two phases, an energy producing phase followed by a release phase. The release phase is one where emphasis should be primarily on obtaining proper club face alignment, not on power slugging the club through impact. Very much like Michael Jacobs’ teaching approach (post #98}. A little bit of freewheeling through the shot is not too bad. A golfer by the name of Bobby Jones did not do all too bad with it.
The only sound way to try to increase impact speed somewhat, close to impact, is not by accelerating the hands along the target line but by raising the swing center; hence by pulling on the handle, perpendicular to the target line. Perhaps not readily intuitively understood. Scientifically the reason is that with the clubhead close to impact the centripetal force is at its maximum and pulling inwards/upwards on the handle constitutes considerable work being done and hence ‘injecting’ very fast appreciable kinetic amount of energy into the club head.
The problem with math models is they invariable lack sufficient detail to accurately model actual real-world phenomema. That or faulty assumptions are made at the outset. Its a problem known in the trade as GIGO or Garbage IN Garbage OUT.
In the real world no math model results are ever accepted until the model has been validated by test. Test results are the gold standard of what happens in the real world. For test results we need look no further than to professor Nesbit. He measured actual hand velocity profiles. Guess what... they don't decellerate prior to impact like mandrin's math model suggest. Seems the human machine (of better golfers anyway) is perfectly capable of accelerating the hands right up to impact:
Velocity:
http://www.jssm.org/vol4/n4/17/F4.htm
Acceleratation:
http://www.jssm.org/vol4/n4/17/F5.htm
How can this be? Simple... Its a matter of muscles... if the power source (muscles or motor) is sufficiently large it simply overcomes the increased load imposed by changing inertia. Think of it this way.... ever step on the gas pedal while driving your car? What happens. Why sometimes one can even accelerate while climbing a hill! Imagine that.
The golfswing is a gestalt... the notion of "constant effort" never enters into the equation. GIGO.
Are we now morphing the discussion into what causes a slice? I can go there. Let me start by saying is not accelerating ones hands into impact like Nesbit's scratch golfer.
In the real world no math model results are ever accepted until the model has been validated by test. Test results are the gold standard of what happens in the real world. For test results we need look no further than to professor Nesbit. He measured actual hand velocity profiles. Guess what... they don't decellerate prior to impact like mandrin's math model suggest. Seems the human machine (of better golfers anyway) is perfectly capable of accelerating the hands right up to impact:
Velocity:
http://www.jssm.org/vol4/n4/17/F4.htm
Acceleratation:
http://www.jssm.org/vol4/n4/17/F5.htm
How can this be? Simple... Its a matter of muscles... if the power source (muscles or motor) is sufficiently large it simply overcomes the increased load imposed by changing inertia. Think of it this way.... ever step on the gas pedal while driving your car? What happens. Why sometimes one can even accelerate while climbing a hill! Imagine that.
The golfswing is a gestalt... the notion of "constant effort" never enters into the equation. GIGO.
Are we now morphing the discussion into what causes a slice? I can go there. Let me start by saying is not accelerating ones hands into impact like Nesbit's scratch golfer.
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Suggest you read the entire paper... it takes some thinking effort on the reader's part but It does make sense. This from the text:
...."For example, the magnitude of the grip velocity agrees well with Vaughn (1979), however there was not the significant reduction in hand speed prior to impact as reported and which is also discussed by Cochran and Stobbs (1969)"....
For the record... I could care less if someone wants to swing their golf club like a "girly man". If they want to slow their hands prior to impact that fine by me... just so long as the don't want to always be teeing off from the ladies tee too. There is a reason Tiger is #1. He's the picture of fitness. I seriously doubt he has slowing hands. As for some of the others though... How those tubs of lard are even able to make it through a round is beyond me. I bet they've got slowing hands.... especially by the end of the day. Whatever... its not the end of the world if someone does. Just one of the (many) details that separates the good from the well... not so good.
Brian Manzella
Administrator
"Girly Men, Math, and total BS."
Nm,
You are totally off-base on this one.
The fact is this: great ball striking existed in the day of the hickory shaft with Vardon, and was modernized by the steel shaft and the dawn of Byron Nelson.
Nelson, Snead and Hogan would have produced WONDERFUL results on the 3D machines, and on TRACKMAN.
What a waste of time to do math, physics or any kind of model that does not show that Nicklaus did it right.
The Hands slow. They did for Bobby Jones, and they did for Steve Jones.
The kinetic chain snaps with VIOLENT shoulder, then hip, then arm deceleration. It did for Walter Hagan, and it did for Ben Creshaw, playing with Walter Hagans.
I have NEVER had to teach someone to slow their hands, but maybe one day I will.
Hopefully all the other teachers will try to speed up the hands during impact and I can pay off my house quicker.
Good job, Mandrin.
Nm,
You are totally off-base on this one.
The fact is this: great ball striking existed in the day of the hickory shaft with Vardon, and was modernized by the steel shaft and the dawn of Byron Nelson.
Nelson, Snead and Hogan would have produced WONDERFUL results on the 3D machines, and on TRACKMAN.
What a waste of time to do math, physics or any kind of model that does not show that Nicklaus did it right.
The Hands slow. They did for Bobby Jones, and they did for Steve Jones.
The kinetic chain snaps with VIOLENT shoulder, then hip, then arm deceleration. It did for Walter Hagan, and it did for Ben Creshaw, playing with Walter Hagans.
I have NEVER had to teach someone to slow their hands, but maybe one day I will.
Hopefully all the other teachers will try to speed up the hands during impact and I can pay off my house quicker.
Good job, Mandrin.
mandrin
New
dbl,
Good to point this out immediately. It appears indeed major. Results shown are not correct and in flagrant contradiction. It definitely casts a very serious shadow on the whole paper since it invites serious questions about the accuracy and/or interpretation of the measurements.
Measurements are only valid if they are correct. Using measurements to argument for the simple fact that they are are measurements is rather naïve and isn’t done by any serious scientist. Measurements when complex and complicated to process, need independent conformation by another independent source to augment their value.
It is however so simple, it suffices to look at the swing vison video quite often shown on TV to immediately see the simple naked truth. But you can lead a horse to water but you can't make it drink.
Girly Man TW
I thought we brought this up last time we discussed the Nesbit article, but where the heck is he measuring hand speed anyway? Never did find it in his article.
I would measure it at the heel pad of the left hand for a righty. An approximation would be to measure angular velocity of the left arm which I did for Tiger from a high-speed video Brian had posted quite awhile back. From about half way down until just before impact he's rotating at around 730 degrees/sec but just before impact (~.03 sec) to impact his left arm rotates at about 230 degrees/sec. Just watching the video in slow motion the slow down is noticeable. Just saying......
I thought we brought this up last time we discussed the Nesbit article, but where the heck is he measuring hand speed anyway? Never did find it in his article.
I would measure it at the heel pad of the left hand for a righty. An approximation would be to measure angular velocity of the left arm which I did for Tiger from a high-speed video Brian had posted quite awhile back. From about half way down until just before impact he's rotating at around 730 degrees/sec but just before impact (~.03 sec) to impact his left arm rotates at about 230 degrees/sec. Just watching the video in slow motion the slow down is noticeable. Just saying......
Its possible to swing a golf club a million of different ways, all of which will move the ball down the fairway. I'm not saying Bobby Jones, Harry Vardon or Byron Nelson weren't good in their day. Its also possible their hands slowed down... So what.
Its (almost) impossible to measure hand speed any other way than Nesbit did.
V = (Vx^2 + Vy^2 +Vz^2)^1/2
You cannot get or estimate all three of those components of velocity from a single piece of video footage. Its impossible. Also what were you looking at? Was it an all out driver swing or some little 100 yrd pitch? It does matter. Max club-head speed only matter's with the driver (and perhaps 3 wood). Everything else is a precision shot.
Its clear by the comment above that mandrin (dbl too?) does not understand Nesbit's methodology... Either that or he suffers cognitive dissonance (a refusal to consider or accept concepts or ideas that contradict one's strongly held beliefs).
Nesbit's results are valid. The golfer's hands he analyzed did not slow down appreciably prior to impact.
It is also clear that what is definitely wrong is any analysis that assumes "constant effort". Nesbit's Work and Power article proves that the amount of work done during the downswing is anything but constant. Any conclusion drawn from an analysis that considered "constant effort" are fatally flawed from the outset. In the trade we call results like those: Color for Dummies or CFD.
In a nutshell: I say slowing hands are not necessary to release the club. Nesbits data proves it. The mathematics proves it. I also say it is possible to accelerate one's hands in to impact. Again Nesbit's data proves it.
Some want to dismiss Nesbit's data because it is at odds with what they "know". Galileo experienced this sort of skepticism too. They locked him in a tower. But hey... its a free country. People can believe what ever they choose to believe. All that means is we are at an impass... a fork in the road. You go your way(s) and I'll go where the evidence leads me.
PS It occurs to me the mandrin might be either Cochran or Stobbs. Everytime anyone points out the discrepencies in their "work" he gets real defensive. mandrin are you cochran or stobbs? Either way... carry on.
Its (almost) impossible to measure hand speed any other way than Nesbit did.
V = (Vx^2 + Vy^2 +Vz^2)^1/2
You cannot get or estimate all three of those components of velocity from a single piece of video footage. Its impossible. Also what were you looking at? Was it an all out driver swing or some little 100 yrd pitch? It does matter. Max club-head speed only matter's with the driver (and perhaps 3 wood). Everything else is a precision shot.
Its clear by the comment above that mandrin (dbl too?) does not understand Nesbit's methodology... Either that or he suffers cognitive dissonance (a refusal to consider or accept concepts or ideas that contradict one's strongly held beliefs).
Nesbit's results are valid. The golfer's hands he analyzed did not slow down appreciably prior to impact.
It is also clear that what is definitely wrong is any analysis that assumes "constant effort". Nesbit's Work and Power article proves that the amount of work done during the downswing is anything but constant. Any conclusion drawn from an analysis that considered "constant effort" are fatally flawed from the outset. In the trade we call results like those: Color for Dummies or CFD.
In a nutshell: I say slowing hands are not necessary to release the club. Nesbits data proves it. The mathematics proves it. I also say it is possible to accelerate one's hands in to impact. Again Nesbit's data proves it.
Some want to dismiss Nesbit's data because it is at odds with what they "know". Galileo experienced this sort of skepticism too. They locked him in a tower. But hey... its a free country. People can believe what ever they choose to believe. All that means is we are at an impass... a fork in the road. You go your way(s) and I'll go where the evidence leads me.
PS It occurs to me the mandrin might be either Cochran or Stobbs. Everytime anyone points out the discrepencies in their "work" he gets real defensive. mandrin are you cochran or stobbs? Either way... carry on.
Oh... one more thing...
Jmessner go here:
http://www.jssm.org/search.php
and search on "nesbit". Start with 3D Kinematics ... then read the Work and Power paper. Its great stuff for the technically inclined.
Jmessner go here:
http://www.jssm.org/search.php
and search on "nesbit". Start with 3D Kinematics ... then read the Work and Power paper. Its great stuff for the technically inclined.
Bronco Billy
New member
Necessary and Sufficient Conditions for Release....
Mandrin....
1. Does Iron Byrons Free Hinge slow down Pre Collision?
2. Does Your Mathematical model of a Double Pendulum require the Free Hinge to Slow Down to Affect a Release?
3. Is it a Necessary Condition for a Golfer's Hands to slow Down to Affect a Release?
Thanks
Mandrin....
1. Does Iron Byrons Free Hinge slow down Pre Collision?
2. Does Your Mathematical model of a Double Pendulum require the Free Hinge to Slow Down to Affect a Release?
3. Is it a Necessary Condition for a Golfer's Hands to slow Down to Affect a Release?
Thanks
For those who have a desire to be led.... be careful who you choose.
Getting published in a scientific journal is NOT and easy process. Its nothing like submitting an article to a monthy rag like Golf Digest or even publishing your own book. Before a paper is accepted for publication in a scientific journal it is subjected to a rigorus "peer review" process. Believe me... peers love to find mistakes in either results or methodology in the work of others. In the publish or perish world of achedemia people's careers and reputations ARE ON THE LINE. That Nesbit's papers made it through that scrutiny and into print speaks volumes.... far more than the undefended dismissal by an anonymous "mandrin" on an online forum which personally I find offensive.
Getting published in a scientific journal is NOT and easy process. Its nothing like submitting an article to a monthy rag like Golf Digest or even publishing your own book. Before a paper is accepted for publication in a scientific journal it is subjected to a rigorus "peer review" process. Believe me... peers love to find mistakes in either results or methodology in the work of others. In the publish or perish world of achedemia people's careers and reputations ARE ON THE LINE. That Nesbit's papers made it through that scrutiny and into print speaks volumes.... far more than the undefended dismissal by an anonymous "mandrin" on an online forum which personally I find offensive.
mandrin
New
Brian,
Thanks, for your appreciation. If serious scientific considerations are fully backed by a person like you having spent all his life researching and teaching golf it has appreciable value over and above some fancy unrealistic wishy-washy ideas forwarded by some. Moreover, the simple truth is there for all to see on TV during any golf tournament but some refuse to drink being lead led to water.
You recently recommended Prof. Jorgensen’s “The Physics of Golf”. I am afraid that this book is now also judged to be worthless and just good for dummies. Judge for yourself. With one phrase (below) all of Jorgensen’s work is judged totally useless. What a silly arrogant pretension. It just so happens that Jorgensen used a ‘constant effort’ in his mathematical model. This confirmed by his measurements proved to be not only adequate but rather surprisingly accurate.
(Nm):"Any conclusion drawn from an analysis that considered "constant effort" are fatally flawed from the outset. In the trade we call results like those: Color for Dummies or CFD."
Facts be damned... seems this "discussion" is turning into a contests of who can "kiss butt" best. I want no part of that. BTW mandrin... "two wrongs equals a right" is another of your logical fallacies. Only fool would argue Jorgensens' (or Cochran and Stobbs) simplistic models are better than whats being done by better scientists today.
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