WHERE'S THE TORQUE?? - by Brian Manzella

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Brian Manzella

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THETORQUE.jpg





<iframe src="http://player.vimeo.com/video/39031201?title=0&byline=0&portrait=0" width="700" height="525" frameborder="0" webkitAllowFullScreen mozallowfullscreen allowFullScreen></iframe>
 
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SteveT

Guest
A THREE DIMENSIONAL KINEMATIC AND KINETIC STUDY
OF THE GOLF SWING

Steven M. Nesbit
Department of Mechanical Engineering, Lafayette College, Easton, PA, USA

Published (online): 01 December 2005

Excerpt:
" The reference coordinate system,
established when the subject addresses the ball,
places the X-axis (alpha) perpendicular to the club
shaft and aligned with the bottom edge of the club
face as viewed down the club shaft, the Z-axis
(gamma) pointing down the club shaft, and the Y-
axis (beta) completing a right-handed coordinate
system.

The alpha component coincides with the
swing angular motion, the beta component is a
measure of the pitch motion of the club relative to
the swing, and the gamma component is the roll
angular motion about the long axis of the shaft."
Click to expand...

Hope that helps ..... SteveT
 
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bluebird

New
Thanks Brian. The beta torque is hard to explain and understand. I understand using beta to correct path issues but am not to shure how it adds to velocity if at all. My fast tempo and short swing seem void of any beta, is this ok?

John
 
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Kevin Shields

Super Moderator
Bluebird, imagine the plane of the hands in the downswing. Just move the club behind then in front of that path or plane. Away from and toward the target line.
 
ZAP

ZAP

New
After watching the longer video and this it is starting to make a lot more sense. The most interesting part is how early those torques are happening.
 
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Jared Willerson

Super Moderator
These videos have really made me understand the differences between what we see in still pictures and what is really happening. The "seems as if" era of instruction is being gutted at a really fast rate.

The videos give a better understanding of what is actually happening which, although scientific in nature, can help any golfer differentiate something that can help their game from a lot of the junk that is out there.
 
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bluebird

New
Thanks for the response Kevin, it is much appreciated. To rephrase the question, If a golfer has an acceptabe path already, what is the advantage of adding beta torque?

thanks again John
 
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Kevin Shields

Super Moderator
bluebird said:
Thanks for the response Kevin, it is much appreciated. To rephrase the question, If a golfer has an acceptabe path already, what is the advantage of adding beta torque?

thanks again John
Click to expand...

Brian beat me to it. If you have good hand path, then without a beta torque the clubhead wouldn't get out to the ball. Not seen in the double pendulum model I might add.
 
B

Brian Manzella

Administrator
Here is two GOLD NUGGETs from Dr. Kwon at the WGSC:

1. The only "plane" that matters is the sweetspot plane from 9 to 3.

2. The shoulders turn 10° FLATTER than the "eventual sweetspot plane" (my term) and the hands move 10° STEEPER.
 
S

SteveT

Guest
Brian Manzella said:
Here is two GOLD NUGGETs from Dr. Kwon at the WGSC:

1. The only "plane" that matters is the sweetspot plane from 9 to 3.

2. The shoulders turn 10° FLATTER than the "eventual sweetspot plane" (my term) and the hands move 10° STEEPER.
Click to expand...


1. Is it the sweetspot "plane" or "path" from 9 to 3? I can see a sweetspot path and according to Mike Finney "SteveT....club acts like a center shafted putter around impact because of lead and droop...".

In a dynamic state, the clubhead sweetspot goes from toe up to toe down deflection (as measured by TT ShaftLab) in the 9 to 3 arc segment. This means any "plane" that might exist from the top of the swing to 9 o'clock, it gets twisted by shaft tip droop, which is significant. If there is a sweetspot "plane", I would like it to be fully defined.

2. Difficult to visualize this....:confused:
 
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bluebird

New
First I need to thank and praise you Brian and the gang for willingly helping the golfing community so much.

To be honest my spatial sense is not satisfied with the total picture. Please be forbearing with me. My sense is if I don't get it, then others won't either. The alpha and gamma are explained to my satisfaction, it's the beta that mystifies me. I do understand the tumble and laying off part of beta, it's near impact that I question.
Here's my list of questions.

1. Please identify how the body applies the beta torque as the club approaches impact?

2. . I do not understand why a beta torque is necessary to hit the ball? Isn't it possible to the deliver the ball to low point on plane with parametric acceleration with alpha only?

3. The particular part of the video that puzzles me is in the beta explanation where you talk about " the ramp up, the ramp in, the ramp down"? Perhaps the coordinate system needs to be identified (the up, in, and down are if reference to what? The ground, the plane, or low point, or body)?
 
S

SteveT

Guest
bluebird said:
To be honest my spatial sense is not satisfied with the total picture. .... The alpha and gamma are explained to my satisfaction, it's the beta that mystifies me. I do understand the tumble and laying off part of beta, it's near impact that I question.
Here's my list of questions.

1. Please identify how the body applies the beta torque as the club approaches impact?

2. I do not understand why a beta torque is necessary to hit the ball? Isn't it possible to the deliver the ball to low point on plane with parametric acceleration with alpha only?

3. The particular part of the video that puzzles me is in the beta explanation where you talk about " the ramp up, the ramp in, the ramp down"? Perhaps the coordinate system needs to be identified (the up, in, and down are if reference to what? The ground, the plane, or low point, or body)?
Click to expand...

Here is what I previously posted on this topic from Nesbit's own definitions in his study:

SteveT said:
Excerpt:

"The reference coordinate system,
established when the subject addresses the ball,
places the X-axis (alpha) perpendicular to the club
shaft and aligned with the bottom edge of the club
face as viewed down the club shaft, the Z-axis
(gamma) pointing down the club shaft, and the Y-
axis (beta) completing a right-handed coordinate
system.

The alpha component coincides with the
swing angular motion, the beta component is a
measure of the pitch motion of the club relative to
the swing, and the gamma component is the roll
angular motion about the long axis of the shaft."
Click to expand...


Every "torque" must have a rotative axis around which the torque turns:

Alpha torque -- spinal axis for body torque that is applied to the hands through the arms
Beta torque --- lead shoulder pitch axis for change of swing plane, up/down..back/downswing.
Gamma torque -- shaft axis for "tumble" torque in final release.

I hope I've got it right for the golfer's "feeel" perceptions...;)

If you want Nesbit's discussion on these torques, here are some excerpts from his study:

Figures 7, 8, and 9 illustrate the alpha component of
the angular velocity, angular acceleration, and
torque applied to the grip respectively for the four
subjects. The alpha components indicate the
swinging action of the club and are the most
significant angular motions. ........ The alpha angular
velocity of the club reflects the summation of the
rotation of the upper body with the motion of the
wrists.

The figure clearly shows that the inner hub has
a constantly changing radius which is necessary for
Figure 3 illustrates each swing from a side
view showing the paths of the grip point and club
head mass center. The figure clearly shows that the
swing does not take place in a fixed plane and that
there is significant pitch (beta) motion of the club
during the swing. There appears to be two planes;
one traced out by the club head, and the other by the
path of the hands. The angle between these planes
ranges from 9 to 12 degrees.

Figures 13, 14, and 15 illustrate the gamma
component of the angular velocity, angular
acceleration, and torque respectively for the four
subjects. The gamma angular components indicate
the rolling motion about the long axis of the club
shaft and are important in squaring up the club face
for impact. Figures 13 and 14 reveal that the gamma
motion is significant yielding angular velocity
values that are approximately half of that for the
alpha component, plus the largest angular
acceleration component. While the most important
function of the gamma motion is to square up the
club face for impact, it does contribute to the overall
club head velocity.
Click to expand...

I hope these snippets are helpful, but if you want to put it into a full context with the figures and measurements, you should read the full Nesbit study which you can google the .pdf as:

A THREE DIMENSIONAL KINEMATIC AND KINETIC STUDY OF THE GOLF SWING -- Steven M. Nesbit

(Now that was fun...:p)
 
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bluebird

New
SteveT,

Thanks for the reply.
"The figure clearly shows that the inner hub has
a constantly changing radius which is necessary for
Figure 3 illustrates each swing from a side
view showing the paths of the grip point and club
head mass center. The figure clearly shows that the
swing does not take place in a fixed plane and that
there is significant pitch (beta) motion of the club
during the swing. There appears to be two planes;
one traced out by the club head, and the other by the
path of the hands. The angle between these planes
ranges from 9 to 12 degrees.
This does explain some of the geometry, but what does it say about any torque?

Thanks

John
 
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