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jimmyt

jimmyt

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With the hips rotating.....wouldn't it appear at and just past impact that the arms are further away from the body, when they are really moving in and up the plane to the finish.

I agree with Kevin "So What"?

11 pages on a thread that at the moment in time everyone is refering too can't be controlled regardless of a desired outcome.

I have hit the ball better and longer since the "Ideas" video!
 
Virtuoso

Virtuoso

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At the start of the downswing, the force on the club is tangential. As it moves down, the force becomes progessively exchanged for a more radial force (more normal to the instantaneous center of rotation). While you are doing that a torque must also be applied to square the face angle. Having said that, some will push, some will pull, some will twist and some will twirl...and sometimes rightly so, and sometimes wrongly so. Looks like good golf instructors will still be employed for awhile.
 
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wulsy

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Todd Dugan said:
I've never questioned any findings of force measurement. Never mentioned it. I'm not stupid enough to question the measurements of scientists. My issue is with how those findings have been applied. It has been suggested here that the golfer should try to pull the hands inward toward the body around impact. But the fact is that the hands of great strikers move away from the body past impact. I'd just like to see Brian clairfy this conflict once-and-for-all.
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The answer is in your question Grasshopper.
 
dschultz6072

dschultz6072

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spktho said:
3 wood off the deck, try to extend arms past impact, probably not going to hit the ball.
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Funny how this swing thought has given me some of the best contact and direction I've ever had. I guess it's all in how you interpret it. I'm trying to straighten my right arm from the top until it is fully extended through the ball and I have the sensation I'm throwing the clubhead as well.
 
hp12c

hp12c

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Virtuoso said:
At the start of the downswing, the force on the club is tangential. As it moves down, the force becomes progessively exchanged for a more radial force (more normal to the instantaneous center of rotation). While you are doing that a torque must also be applied to square the face angle. Having said that, some will push, some will pull, some will twist and some will twirl...and sometimes rightly so, and sometimes wrongly so. Looks like good golf instructors will still be employed for awhile.
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dude u know what i just did, no u dont ur not in my head r u? I was reading what u wrote and was using Bmanz voice, R u Bmanz alter ego? u sound just like Bmanz in my head.:D
 
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spktho

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So, you're on the lesson tee as a student or an instructor and you are working on extending the arms past impact. The golfer starts hitting low necked fades. The pivot and everything else looks good. They are instructed to extend more past impact. They start standing up and raising the handle into impact and hit toed draws. Seems to me there is another option discussed in this thread to help.

But a golfer never does this.....:rolleyes:
 
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art

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art said:
Dear puttmaster,

Great comment and observation.

In 2007, when I first got curious about ground reaction forces and how in golf they were created, I actually took the fold-out swing sequences in the golf magazines, and with engineering tracing paper, drew the position of the lead shoulder sequentially from each frame for both the head on, and down the line views.

For sure, the lead shoulder is going up (or sometimes and unfortunately horizontally for amateurs), and for good reason. From simple geometry, the angle between the arms and the club at address and impact are different necessitating ALWAYS, a movement of the lead shoulder to a more distant location at impact thru full extension of both arms.

This is the time period being discussed here, and another VERY important relevant point is to be made from physics, not geometry.

For a golfer hitting a driver with a swing speed of 100 miles per hour at impact, the centripetal force needed to be keep the club stably on its 'flight path' is almost exactly 100 pounds, and easy to remember. Since the force is a 'square function' with the velocity, a 110 MPH swing develops 121 pounds of force, a 90 MPH, 81 pounds of force etc.

My point is the effect on STABILITY of the flight path of the club. If that centripetal force is not RESISTED exactly, the club will drift AWAY from the intended path. Conversely, if MORE than the centripetal force is exerted on the grip in a pulling direction, the path will be changed, but the physics suggests that 'parametric acceleration' will occur, with a resultant increase in club head velocity.

So, IMO, even though subjective, throwing the club head off the shaft, and pulling on the shaft could result in very different club head dynamic, and flight path conditions.

Sincerely,
art
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As this thread continued from this Post #60, to its present length of at least #113, I realized I did not go far enough in describing the forces being applied to the entire body due to the many rotating parts.

Above, I got into the club's effect on the hands, and introduced the torso's effect on the hips, but I did not describe the rotating arm(s) centripetal forces pulling on the shoulders. To envision the magnitude, and much more importantly the instantaneous 3D DIRECTION of these 4 forces (club to hands, arms to shoulders, torso to pelvis, and pelvis to feet/ground), is , as you have guessed, a monumental job that I have only done once, by hand. (I have tried to encourage scientists with refined computer models to do this 'automatically' with a software module, and am presently awaiting an opportunity to present my work to Taylor, using their MATT;s system as the basis for the raw data).

At any rate, as mandrin would say, "as a first order approximation", from basic data using the AMM/TPI 12 sensor system, and for one swing of one golfer, I found centripetal forces during the downswing over 100 pounds, but at different times, and in different directions, for ALL four of the rotating elements noted above, with the 3D values of rotational velocity and acceleration/deceleration from the 'kinematic sequence' graphs provided by the software, and data noted every 0.004 seconds.

So, what does all this mean to the ORIGINAL question of a release that 'throws the club head off the shaft', or a release that as 'Virtuoso' so aptly put it, "At the start of the downswing, the force on the club is tangential. As it moves down, the force becomes progressively exchanged for a more radial force (more normal to the instantaneous center of rotation)"?

It simply means that there are 4 MAJOR forces ON THE BODY during the downswing ALL over 100 pounds at one time or another, ALL pulling radially, from their 'instantaneous centers of rotation', and in my hopefully 'applied scientific opinion', displacing the relative locations of the moving body on video in ways that change AND ARE DIFFERENT for every golfer, and maybe for every swing.

What IMO remains the same however, are the relative movement similarities shortly before and after impact where the angular velocities, and therefore the centripetal forces are reasonably proportional to the quality of the golfer, ie., high quality, high forces, and therefore larger displacements, or significantly more strength required to control the movement from the high forces.

Finally, I see the 'throwing the club head off the shaft' as a more violent approach to rotating around the coupling point, and believe that both result in higher club head velocities at impact. Therefore, both provide the environment BY THE BODIES NATURAL REACTIONS and desire to hit the ball squarely, in a 'radial', or normal restraining and 'pulling' force creating the environment for additional 'parametric acceleration' benefits, but only if IF TIMED CORRECTLY. And that is where I switch to OPINION, for IMO, any 'throwing' actively during the downswing has a high potential for developing undesirable timing, path, and club head position errors that I BET YOU will easily show up in inaccuracy and more dispersion, consistently.

Hope this helps shed a little light as to why , when keeping the center of the ball CONSTANT, the body has such a hard job to do dynamically balancing these disturbing centripetal forces, while accommodating very accurately, the total length of the golf club and the arms/body in the midst of this 'storm' of changing forces. So I see the relative positions of a golfer on video, as a 'fingerprint', as to how they are accomodating these changing forces, and by NO means a source to estimate these forces.
 
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art

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hp12c said:
Art can u discuss futher these 4 forces.
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Sure hp12c, I will be glad to further discuss these forces.

The easiest to discuss is the force developed by the club on the hands as the downswing progresses, so lets start with the golf club forces.

If you were lucky enough to have access to MATT's, or the TPI/AMM systems (and to a degree K-Vest), you would be able to 'see' the angular velocity of the club, lead arm and upper body angular velocities as the swing progressed. These graphs are called the 'kinematic sequences', and for the club, usually goes from 0 to over 2000 degrees per second in about 0.25 to 0.30 seconds. As previously noted produces 'centripetal and tangential forces' that vary with position and time. But, at or near impact, the forces are predominantly centripetal, so this approximate 100 pounds is PULLING on the hands, and therefore on the body too by this amount. Earlier in the downswing, the size AND 3D DIRECTION of this club-created force is very different.

Next, the centripetal forces produced by the rotating arms around the spine for the lead arm alone are moving at 600 degrees a second, and at this peak, about 2/3 of the downswing time also develop over 100 pounds of force, which PULLS on the top of the torso, through the shoulders. Again, later in the swing, the 3D direction and value of the forces are reduced due to the deceleration as noted by the kinematic sequence characteristics, which PROBABLY differ by individual, club and maybe every swing.

Finally, for the FORWARD FORCE DISTURBANCES, the torso rotating around the spine at over 400 degrees per second, and weighing the most of the 4 rotating parts, because of its large moment of inertia, also develops over 100 pounds of centripetal force at its peak, also about 2/3 of the downswing tim. Like the arms, however, it also decelerates from this peak angular velocity, and at impact is less than half the velocity, and therefore less than 1/4 the force. But the 3D direction of these forces are very different than the club and arms vectors, necessitating an instant by instant 'vector addition' of these forces.

The 4 th force is created by the rotating pelvis and legs, and because of a greatly dispersed location of the 'instantaneous axis of rotation', can produce BOTH additional disturbances OR, if BBKIB is utilized, a stabilizing vector against the other 3, resulting in a more balanced swing.

I realize that as the angular velocities for the 4 elements develop, there are INTERNAL reactions to the torques that produce these body rotations, but as previously noted above, this is just a 'FIRST ORDER' analysis of what happens kinetically during the explosive downswing.

This has led to a new hypothesis, as yet unproven, that the foot reaction forces, in 6D, and obtained from high quality, high response force plates are the LEFT OVER FORCES not accommodated by the bodies compensations. If true, these ground reaction force vectors may be able to 'immediately' detect the degree of dynamic IMBALANCE that must be generated for a well balanced golf swing.

Thanks for asking.

Regards,
art
 
hp12c

hp12c

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art said:
Sure hp12c, I will be glad to further discuss these forces.

The easiest to discuss is the force developed by the club on the hands as the downswing progresses, so lets start with the golf club forces.

If you were lucky enough to have access to MATT's, or the TPI/AMM systems (and to a degree K-Vest), you would be able to 'see' the angular velocity of the club, lead arm and upper body angular velocities as the swing progressed. These graphs are called the 'kinematic sequences', and for the club, usually goes from 0 to over 2000 degrees per second in about 0.25 to 0.30 seconds. As previously noted produces 'centripetal and tangential forces' that vary with position and time. But, at or near impact, the forces are predominantly centripetal, so this approximate 100 pounds is PULLING on the hands, and therefore on the body too by this amount. Earlier in the downswing, the size AND 3D DIRECTION of this club-created force is very different.

Next, the centripetal forces produced by the rotating arms around the spine for the lead arm alone are moving at 600 degrees a second, and at this peak, about 2/3 of the downswing time also develop over 100 pounds of force, which PULLS on the top of the torso, through the shoulders. Again, later in the swing, the 3D direction and value of the forces are reduced due to the deceleration as noted by the kinematic sequence characteristics, which PROBABLY differ by individual, club and maybe every swing.

Finally, for the FORWARD FORCE DISTURBANCES, the torso rotating around the spine at over 400 degrees per second, and weighing the most of the 4 rotating parts, because of its large moment of inertia, also develops over 100 pounds of centripetal force at its peak, also about 2/3 of the downswing tim. Like the arms, however, it also decelerates from this peak angular velocity, and at impact is less than half the velocity, and therefore less than 1/4 the force. But the 3D direction of these forces are very different than the club and arms vectors, necessitating an instant by instant 'vector addition' of these forces.

The 4 th force is created by the rotating pelvis and legs, and because of a greatly dispersed location of the 'instantaneous axis of rotation', can produce BOTH additional disturbances OR, if BBKIB is utilized, a stabilizing vector against the other 3, resulting in a more balanced swing.

I realize that as the angular velocities for the 4 elements develop, there are INTERNAL reactions to the torques that produce these body rotations, but as previously noted above, this is just a 'FIRST ORDER' analysis of what happens kinetically during the explosive downswing.

This has led to a new hypothesis, as yet unproven, that the foot reaction forces, in 6D, and obtained from high quality, high response force plates are the LEFT OVER FORCES not accommodated by the bodies compensations. If true, these ground reaction force vectors may be able to 'immediately' detect the degree of dynamic IMBALANCE that must be generated for a well balanced golf swing.

Thanks for asking.

Regards,
art
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Art this part of ur post caugh my eye. Is this true on all clubs.

"But, at or near impact, the forces are predominantly centripetal, so this approximate 100 pounds is PULLING on the hands, and therefore on the body too by this amount."
 
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art

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hp12c said:
Art this part of ur post caugh my eye. Is this true on all clubs.

"But, at or near impact, the forces are predominantly centripetal, so this approximate 100 pounds is PULLING on the hands, and therefore on the body too by this amount."
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Dear hp12c,

The 'characteristic' is true for all clubs, and all full swings BUT, the centripetal force developed is determined by the club head velocity, the length of the shaft, and the weight of the club. So, the driver produces the largest force, and the wedges, the lowest force.

The actual equation used to determine these centripetal forces is: Force = mass times velocity squared divided by the length of the club.

And since the velocity = the radius times the angular velocity, Force = mass times the angular velocity squared times the length of the club.

Regards,
art
 
hp12c

hp12c

New
art said:
Dear hp12c,

The 'characteristic' is true for all clubs, and all full swings BUT, the centripetal force developed is determined by the club head velocity, the length of the shaft, and the weight of the club. So, the driver produces the largest force, and the wedges, the lowest force.

The actual equation used to determine these centripetal forces is: Force = mass times velocity squared divided by the length of the club.

And since the velocity = the radius times the angular velocity, Force = mass times the angular velocity squared times the length of the club.

Regards,
art
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Art thank you for the further eplanation. I want to make sure I understand this pulling force. When I swing full with a 5 iron its pulling on my hands,arms, shoulders, torso as if I was swinging a 100lb weight is that correct?
 
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