Jeff, if you notice, the grip is indeed at maximum speed at impact. But it has reached that speed well before. Notice how the graph plateaus; the grip appears to stop accelerating at about .05 seconds before impact. Maybe the confusion with this topic is due to speaking of absolute speed (slowing down, stopping), as opposed to acceleration?
hitting against a firm left side?? (SUBJECT of a NEW! Manzella YouTube!)
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jeffy
Banned
Crude, but effective, as well as indisputable. No need to gold-plate the crowbar.
Looking at Hogan's right shoulder in the iron swing that appears in the opening segment of the Shell broadcast, it looks to me that it effectively stops one "click" before impact.
Brian - I am still open-minded about the question whether the hands slow down before impact (your position) or don't slow down before impact (Nesbit's position).
I therefore did a crude practical experiment, which supports your position that the conjoined hand unit slows down before impact.
I tried to advance some of my Ben Hogan videos frame-by-frame in my V1Home Swing analyser program to see if I could measure the distance the hands travel between each frame. That proved to be impossible, because those old films were presumably filmed at 30 frames/second. I could only capture 1-2 frames between the delivery position and the impact position.
I therefore repeated the experiment using a video of Tiger Woods swing taken with a BIzHub camera, that apparently captures 500 frames/ second.
I used this swing video
http://www.youtube.com/watch?v=yqsf4bEBF-Q&mode=related&search=
This was my result
I used the spline tool to trace the movement of the hands in the downswing. Because of the high camera speed (? 500 frames/second) the hands hardly seemed to move if I advanced the video frame-by-frame. I therefore made a click with the spline tool every 4 frames - so each white dot in the hand path represents the distance the hands moved during the time period of 4 frames. Also, the time difference between each image in the sequence of images 1-5 represents 4 frames.
One can see (from images 1-5) that the white dots are closer together as the hands approach impact - suggesting that the hands slow down prior to impact.
This crude experiement suggests that Nesbit may be wrong, but I don't know if my technique is a valid method of accurately assessing the speed of hand movement in the downswing.
Interestingly, image 6 shows where Tiger Woods hands are when the release starts to happen (roughly at the delivery position). At that point in time, the hands are not slowing down - suggesting that the release phenomenon is not dependent on slowing down of the hands.
Jeff.
I therefore did a crude practical experiment, which supports your position that the conjoined hand unit slows down before impact.
I tried to advance some of my Ben Hogan videos frame-by-frame in my V1Home Swing analyser program to see if I could measure the distance the hands travel between each frame. That proved to be impossible, because those old films were presumably filmed at 30 frames/second. I could only capture 1-2 frames between the delivery position and the impact position.
I therefore repeated the experiment using a video of Tiger Woods swing taken with a BIzHub camera, that apparently captures 500 frames/ second.
I used this swing video
http://www.youtube.com/watch?v=yqsf4bEBF-Q&mode=related&search=
This was my result
I used the spline tool to trace the movement of the hands in the downswing. Because of the high camera speed (? 500 frames/second) the hands hardly seemed to move if I advanced the video frame-by-frame. I therefore made a click with the spline tool every 4 frames - so each white dot in the hand path represents the distance the hands moved during the time period of 4 frames. Also, the time difference between each image in the sequence of images 1-5 represents 4 frames.
One can see (from images 1-5) that the white dots are closer together as the hands approach impact - suggesting that the hands slow down prior to impact.
This crude experiement suggests that Nesbit may be wrong, but I don't know if my technique is a valid method of accurately assessing the speed of hand movement in the downswing.
Interestingly, image 6 shows where Tiger Woods hands are when the release starts to happen (roughly at the delivery position). At that point in time, the hands are not slowing down - suggesting that the release phenomenon is not dependent on slowing down of the hands.
Jeff.
Jeff,
If you accept the premise that the wrists and right elbow are not (conciously) part of the release, then the club will only release if the left arm slows slightly, allowing the levers to release....
If the left arm doesn't slow, the only way the club can release is by active force/input from the wrist or right elbow lever....
Go buy a bullwhip and see if you can get it to crack without slowing your arms...
or use a wet towel.....
Think of a wheel with a rod attached (free-hinge) to the outer rim...if you spin the wheel at a constant rate the rod will always be "cocked" or lagging at a tangent to the outer wheel's circumference.. Only when the wheel slows will the rod break the cocked angle and start to straighten itself in line with the radius of the wheel..
That's my way of understanding it, Mandrin and nm may disagree....
If you accept the premise that the wrists and right elbow are not (conciously) part of the release, then the club will only release if the left arm slows slightly, allowing the levers to release....
If the left arm doesn't slow, the only way the club can release is by active force/input from the wrist or right elbow lever....
Go buy a bullwhip and see if you can get it to crack without slowing your arms...
or use a wet towel.....Think of a wheel with a rod attached (free-hinge) to the outer rim...if you spin the wheel at a constant rate the rod will always be "cocked" or lagging at a tangent to the outer wheel's circumference.. Only when the wheel slows will the rod break the cocked angle and start to straighten itself in line with the radius of the wheel..
That's my way of understanding it, Mandrin and nm may disagree....
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jeffy
Banned
Nice of you to finally getting around to confirming the facts I've already presented instead of dismissing them and continuing to spout off.
An obvious explanation for Nesbit's graph is that he is measuring linear velocity, while what we "see" slowing in the videos is angular velocity (since the swing is in a circle). Linear velocity is a function of both angular velocity as well as the length of the radius: at a constant angular velocity, the linear velocity will go up if the radius increases. Because of the straightening of the right arm, the swing radius of the grip "grows" in the downswing. Although it seems like a bit of a coincidence that the "growing radius" would offset exactly the decrease in angular velocity, that is one straightforward explanation for the apparent discrepancy of Nesbit's graph.
In addition, the linear speed of the "grip" will be influenced by exactly WHERE on the grip Nesbit measured the linear velocity. As the wrists uncock, the radius of the club changes. If it were measured at the butt-end (above where the left hand is attached to the grip), that would be the slowest, as the butt-end would be traveling away from the target, and the radius shrinking, as the wrists uncocked. If he measured at a point somewhere below where the pinky of the left hand holds the grip, the radius of that point will increase as the wrists uncock.
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Puttmad
Your explanation doen't make sense- from my perspective. The Pingman machine is really equivalent to a "wheel with a rod attached (free-hinge) to the outer rim" that is spinning at a constant rate - but the release still occurs. As nmgolfer explained, the club develops angular momentum even if the grip end of the club is pulled along at a CONSTANT speed - and the angular momentum develops because the linear force pulling the grip end of the club doesn't pass through the COG of the club.
The bulwhip is like a flail, where the central handle slows down and energy is transferred to the far end of the whip causing it to speed up. However, nmgolfer showed that the bullwhip model doesn't apply to the golf swing - because the COG of the golf club is close to the far end of the club and not at, or near, the handle.
Jeff.
Your explanation doen't make sense- from my perspective. The Pingman machine is really equivalent to a "wheel with a rod attached (free-hinge) to the outer rim" that is spinning at a constant rate - but the release still occurs. As nmgolfer explained, the club develops angular momentum even if the grip end of the club is pulled along at a CONSTANT speed - and the angular momentum develops because the linear force pulling the grip end of the club doesn't pass through the COG of the club.
The bulwhip is like a flail, where the central handle slows down and energy is transferred to the far end of the whip causing it to speed up. However, nmgolfer showed that the bullwhip model doesn't apply to the golf swing - because the COG of the golf club is close to the far end of the club and not at, or near, the handle.
Jeff.
mandrin
New
puttmad,Jeff,
If you accept the premise that the wrists and right elbow are not (conciously) part of the release, then the club will only release if the left arm slows slightly, allowing the levers to release....
If the left arm doesn't slow, the only way the club can release is by active force/input from the wrist or right elbow lever....
Go buy a bullwhip and see if you can get it to crack without slowing your arms...
Think of a wheel with a rod attached (free-hinge) to the outer rim...if you spin the wheel at a constant rate the rod will always be "cocked" or lagging at a tangent to the outer wheel's circumference.. Only when the wheel slows will the rod break the cocked angle and start to straighten itself in line with the radius of the wheel..
That's my way of understanding it, Mandrin and nm may disagree....
I don’t agree with Nesbit’s way of handling the role of bending of shaft.
Jeffmann, now starts to feels that his own measurements contradict Nesbit’s work.
It shows that one should always be very careful to take the word of a scientist as the absolute truth.
nmgolfer however swears by Nesbit, considering it very serious and worthwhile research.
It is probably where he finds his inspiration for his ideas about hand speed through impact.
But there will always be Don Quichottes fighting windmills, and I hope it stays that way for its entertainment value.
jeffy
Banned
Well, well well. I went to Nesbit's article and you have misrepresented his position. Nowhere does he say that the hands "don't slow down before impact". To the contrary, he says the opposite.
Regarding linear velocity of the grip, he says this:
"Generally, the maximum grip velocity was reached just before impact and remained constant or decreased slightly through impact."
Regarding angular velocity of the grip, he says this:
"The maximum swing angular velocity consistently occurred 0.025 seconds before impact for the scratch golfer..."
For those interested, you can find the article here (the relevant discussion takes place on pages 8, 9 and 10):
http://www.jssm.org/vol4/n4/17/v4n4-17pdf.pdf
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jeffy
Banned
Not exactly; his measurements, in fact, confirm Nesbit's work. See my post immediately above.
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...
So Jeff,
What if you had a shaft with a centrally fixed weight on it. Would that release the same?...
When pingman starts down doesn't the shaft bend slightly? Which means initially the grip accelerates faster than the head...And wouldn't that bend (straightening) add impetus or initiate the club releasing?...
So Jeff,
What if you had a shaft with a centrally fixed weight on it. Would that release the same?...
When pingman starts down doesn't the shaft bend slightly? Which means initially the grip accelerates faster than the head...And wouldn't that bend (straightening) add impetus or initiate the club releasing?...
Puttmad
I don't have the expertise to answer your question. It was nmgolfer who brought forward the suggestion that the club develops angular momentum because the linear force moving the grip doesn't pass through the COG of the club. I don't know what effect wil occur when the COG moves to dfiferent positions along the shaft so that the COG is a different distance from the end of the club.
Consider this comment-: "Well, well well. I went to Nesbit's article and you have misrepresented his position. Nowhere does he say that the hands "don't slow down before impact". To the contrary, he says the opposite.
Regarding linear velocity of the grip, he says this:
"Generally, the maximum grip velocity was reached just before impact and remained constant or decreased slightly through impact.""
My reply - The data was already presented in a previous post via this graph.
The velocity reaches a plateau around 0.05 seconds prior to impact, and there is no decrease in velocity by impact. It is essentially at maximum velocity in the peri-impact phase of impact (within 0.05 seconds of impact - preimpact or postimpact).
Jeff.
I don't have the expertise to answer your question. It was nmgolfer who brought forward the suggestion that the club develops angular momentum because the linear force moving the grip doesn't pass through the COG of the club. I don't know what effect wil occur when the COG moves to dfiferent positions along the shaft so that the COG is a different distance from the end of the club.
Consider this comment-: "Well, well well. I went to Nesbit's article and you have misrepresented his position. Nowhere does he say that the hands "don't slow down before impact". To the contrary, he says the opposite.
Regarding linear velocity of the grip, he says this:
"Generally, the maximum grip velocity was reached just before impact and remained constant or decreased slightly through impact.""
My reply - The data was already presented in a previous post via this graph.
The velocity reaches a plateau around 0.05 seconds prior to impact, and there is no decrease in velocity by impact. It is essentially at maximum velocity in the peri-impact phase of impact (within 0.05 seconds of impact - preimpact or postimpact).
Jeff.
Mandrin - although my crude calculations contradict Nesbit's conclusions, I am very un-confident in my primitive ad hoc technique of estimating the velocity of the conjoined hand unit. I had great difficulty deicding where to place the spline points - eg. at the end of the butt, side of the hand. During the pre-impact phase of the downswing, the left hand rotated 90 degrees and I wonder whether it invalidates my crude technique.
I would also like to read your comments on what causes the release, and whether you think that it is due to the club's angular momentum that the club acquires secondary to the fact that the linear force moving the grip (along a circular path) doesn't pass through the COG of the club.
Jeff.
I would also like to read your comments on what causes the release, and whether you think that it is due to the club's angular momentum that the club acquires secondary to the fact that the linear force moving the grip (along a circular path) doesn't pass through the COG of the club.
Jeff.
jeffy
Banned
No they don't, your depiction of the decline in angular velocity in Tiger's swing confirms Nesbit's observation:
"The maximum swing angular velocity consistently occurred 0.025 seconds before impact for the scratch golfer..."
It is also consistent with his findings regarding linear velocity:
"Generally, the maximum grip velocity was reached just before impact and remained constant or decreased slightly through impact."
Instead of doggedly referring to Figure 4 (which shows linear velocity), why don't you cut and paste Figure 7 from page 10, which shows the angular velocity declining before impact? What's wrong with acknowledging the truth?
Bronco Billy
New member
Brian - I am still open-minded about the question whether the hands slow down before impact (your position) or don't slow down before impact (Nesbit's position).
I therefore did a crude practical experiment, which supports your position that the conjoined hand unit slows down before impact.
I tried to advance some of my Ben Hogan videos frame-by-frame in my V1Home Swing analyser program to see if I could measure the distance the hands travel between each frame. That proved to be impossible, because those old films were presumably filmed at 30 frames/second. I could only capture 1-2 frames between the delivery position and the impact position.
I therefore repeated the experiment using a video of Tiger Woods swing taken with a BIzHub camera, that apparently captures 500 frames/ second.
I used this swing video
http://www.youtube.com/watch?v=yqsf4bEBF-Q&mode=related&search=
This was my result
I used the spline tool to trace the movement of the hands in the downswing. Because of the high camera speed (? 500 frames/second) the hands hardly seemed to move if I advanced the video frame-by-frame. I therefore made a click with the spline tool every 4 frames - so each white dot in the hand path represents the distance the hands moved during the time period of 4 frames. Also, the time difference between each image in the sequence of images 1-5 represents 4 frames.
One can see (from images 1-5) that the white dots are closer together as the hands approach impact - suggesting that the hands slow down prior to impact.
This crude experiement suggests that Nesbit may be wrong, but I don't know if my technique is a valid method of accurately assessing the speed of hand movement in the downswing.
Interestingly, image 6 shows where Tiger Woods hands are when the release starts to happen (roughly at the delivery position). At that point in time, the hands are not slowing down - suggesting that the release phenomenon is not dependent on slowing down of the hands.
Jeff.
Hi Jeff
Nice Post and Analysis..... Here's my Take on it which is Derived from a Post Where Mandrin compared Graphs of a Single and Double Lever Systems which is Sometimes Used to Model a Golf Swing...... The Double Lever System Gains about 50% more Velocity at Impact than the single Lever System... This 50% gain Occurs during Release.... One Does not get something for Nothing except Free Lunch from Brian.... The reason the Arm(Hand/Hinge) Slows is that the Kinetic Energy is Transferred from the Hinge to the ClubHead thus the Speeding up of the ClubHead and the Slowing down of the Hinge.... This Occurance does NOT cause the Release.... It is an Effect and NOT a Cause......
Cheers
Jeff,
If you accept the premise that the wrists and right elbow are not (conciously) part of the release, then the club will only release if the left arm slows slightly, allowing the levers to release....
If the left arm doesn't slow, the only way the club can release is by active force/input from the wrist or right elbow lever....
Go buy a bullwhip and see if you can get it to crack without slowing your arms...
Think of a wheel with a rod attached (free-hinge) to the outer rim...if you spin the wheel at a constant rate the rod will always be "cocked" or lagging at a tangent to the outer wheel's circumference.. Only when the wheel slows will the rod break the cocked angle and start to straighten itself in line with the radius of the wheel..
That's my way of understanding it, Mandrin and nm may disagree....
nm definitely disagrees... the physics of snapping a bullwhip and swinging a golfclub for maximum club head speed at impact are very different.
http://math.arizona.edu/~goriely/Papers/2002-PRL(whip).pdf
I don't care about Hogan (he wasn't known as a particularly long hitter) or anyone else... but Puttmad are you telling me you believe mike austin consciously or otherwise slowed his hands down prior to impact?
mandrin
New
JeffMann,
I thought by now it to be generally accepted knowledge, i.e., hands/arms slowing down prior to impact. For instance, Brian who is trying to be up front in every aspect of golf, believes firmly this to be the case.
I have done enough complex measurements to know that it does not take much to go astray. Hence before I give Nesbit serious consideration I have to see at least another independent serious study confirming his finds.
With regard to treating release, there are several phases/elements to consider - prior to release, release itself and especially the dynamic interaction of various elements such as club and arms. nmgofler does treat release only partially but correctly.
The problem for me is that sometimes things end up in a brawl and there is no place for useful and cordial exchange. However since the subject is indeed interesting I will try to get motivated to post in the near future enough information in such a way that EVERYBODY will be able to fully understand release.
Dear Jeffy,
I do believe you are misinterpreting Nesbit's results. Linear velocity i.e. Vhands = ((dx/dt)^2 +(dy/dt)^2 +(dz/dt)^2))^.5 is what matters. Actually what matters is Vclubhead = Vhands + Vrelative where Vrelative = w X R. w = omega or angular velocity, X is cross product and R is the distance from the grip to the club head.
The scratch golfer (in Nesbit's study) for all practical purposes has maximum CHS at impact. So he's off a nano second or two.. that's splitting hairs. This is not to say his is the only way to swing a golf club or even the best... but its good enough to get him to scratch and it most definitely dispells the myth that hands (must) slow prior to impact. This is Nesbit's own conclusion as detailed in the Summary.
Brian Manzella
Administrator
I have absolutely HAD IT with you guys.
Not one of ya'll have been on a 3D machine, NOT ONE have watched others on a 3D machine.
Therefore, I would ONLY HOPE that the golfers on this site to learn, STOP LISTENING to these folks trying to analyze 2D stills taken at maybe 12 Frames per second, where the CHEAPEST 3D system, uses nearly 250.
The snap of the final segments—the arms and the hands—happen very suddenly, and this PITIFUL 12 Frame per second still "analysis," is nothing more than a WEAK GUESS.
No NM, you don't try to STOP the hands to release.
You set up the stance vs. plane line, and try to get the STUDENT in a proper torso tilted and rotated postition so they CAN sanp it.
Some of you just can't handle that I know this and none of your buddies do, can you?
Not one of ya'll have been on a 3D machine, NOT ONE have watched others on a 3D machine.
Therefore, I would ONLY HOPE that the golfers on this site to learn, STOP LISTENING to these folks trying to analyze 2D stills taken at maybe 12 Frames per second, where the CHEAPEST 3D system, uses nearly 250.
The snap of the final segments—the arms and the hands—happen very suddenly, and this PITIFUL 12 Frame per second still "analysis," is nothing more than a WEAK GUESS.
No NM, you don't try to STOP the hands to release.
You set up the stance vs. plane line, and try to get the STUDENT in a proper torso tilted and rotated postition so they CAN sanp it.
Some of you just can't handle that I know this and none of your buddies do, can you?
puttmad,
I don’t agree with Nesbit’s way of handling the role of bending of shaft.
Jeffmann, now starts to feels that his own measurements contradict Nesbit’s work.
It shows that one should always be very careful to take the word of a scientist as the absolute truth.
nmgolfer however swears by Nesbit, considering it very serious and worthwhile research.
It is probably where he finds his inspiration for his ideas about hand speed through impact.
But there will always be Don Quichottes fighting windmills, and I hope it stays that way for its entertainment value.
You are incorrigible... you've demonstrated little understanding of dynamics (verging on total incompetence) and now you've taken to excoriating (sans details as always which is your motis operandi) a published professor of mechanical engineering who holds a doctorate in the field.... simply because his very detailed results contradict your own simpleton study. What a joke. Now its all about your "reputation"... science be damned isn't in mandrin.... Everything... fine so long as everyone's singing Tammy Wynette's tune re.. standing by her mandrin.
Brian Manzella
Administrator
MR. NM, whoever you are.
You think I favor Mandrin, you are correct, he has contributed to this site over a long period of time.
I have little doubt you are not on my site to LEARN anything from me.
So.....why are you here?
You think I favor Mandrin, you are correct, he has contributed to this site over a long period of time.
I have little doubt you are not on my site to LEARN anything from me.
So.....why are you here?
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