Post by jeffy on Nov 29, 2011 19:21:35 GMT -5
One of things that has always bothered Kelvin about the "kinetic sequence" theory and the graphs produced by today's "state of the art" 3D systems is that they both disagree with his observations. Kinetic sequence theorists believe that in an "efficient" swing each major swing driver successively accelerates then decelerates well before impact, passing along energy to the clubhead. We all know what these graphs look like, Nate P. posted a set the other day:
Despite these "scientific" claims, Kelvin knew that, based on his observation of "elite" players (to Kelvin, "elite" means bombers with enough control to be competitive at the highest level), body rotation did not slow down until after impact.
One piece of scientific evidence supporting Kelvin's observations was this graph from a paper by one of Brian's own experts (Sasho Mackenzie) which concluded that in an optimized swing the trunk would show increasing muscular torque through impact (applying a greater turning force), a result totally at odds with the kinetic sequence deceleration theory and those 3D "representations":
Source: Examining the delayed release in the golf swing using computer simulation, Sprigings and Mackenzie, 2002.
Despite being published nearly ten years ago, golf's "leading scientists" continue to promote the kinetic sequence theory and promote successive deceleration of the hips, shoulders and hands.
As it turns out, and as Kelvin suspected, the 3D devices that Manzella claims to be essential to understanding the golf swing measure the body all wrong. The 3D devices attach about two dozen markers on a player's body then use signals transmitted from the markers to create a "3D model". Sadly, no one bothered to actually LOOK at the real golfers and determine if the models and the golfers actually swung the same way. Turns out that they don't. Unfortunately, the 3D devices appear to measure lateral (toward the target speed), not actual speed, so, as body parts move left, they appear to slow down. Also, it appears that the devices use insufficient markers to accurately capture some critical body movements.
So, you are no doubt asking, where does this new information come from? A Finnish company named 4dswing (https://www.4dswing.com/) has developed a (hold on!) video-based system that captures images of the actual golfer (at anywhere from 100 to 500fps) from all sorts of angles, then calculates movements in 3D based on those images. (This is essentially what Kelvin and Rick Malm did on their own by filming golfers from all angles at 300fps then synchronizing the videos). The poster TeeAce works there and shared this information with Kelvin.
When the body is measured accurately using the 4dswing system, a totally different picture emerges, and one that makes far more intuitive sense than the current "science". Here is a graph that shows what is actually going on in the swing of a young, athletic, multiple winner on the European tour, that hits it and plays pretty good (top 40 driving distance, top 15 Race to Dubai).
It's a little blurry, but what this shows is that there is no sequence at all: hip speed (blue line) peaks at impact; after a brief deceleration, the shoulders (red line) accelerate through impact and peak well after; and the hands (green line) show just a modest tailing off before impact, caused by the increase in moment of inertia as the club and arms unfold. There is NO evidence of any intentional or unintentional slowing of any body part by the player, which, of course, makes perfect sense when you consider that self-taught players like JB and Gainey say that their only "intent" is to hit the ball as hard as they can. I doubt that means decelerating anything before impact.
The 4dswing product isn't ready for commercial roll-out (they plan to add a 2,000fps camera to capture the clubface through impact), so to date they have kept a low profile. Nevertheless, they are well aware that their system blows TPI and other 3D "experts" out of the water, so you'll be hearing a lot more about them in the future, I'm sure!
BTW, the additional 2,000fps camera is intended to address the major failing of Trackman: its inability to measure clubface angle and dynamic loft. Sure, the Trackman device displays a "clubface angle" and "dynamic loft" at impact, but those are not direct measurements for the simple reason that they can't be: Trackman is not capable of measuring that data.
Trackman uses radar shot down the target line, therefore it can't "see" what the clubface is doing near impact (it's not an x-ray device!). What Trackman does is take measurements of clubhead path and initial ball flight then calculates an "estimated" clubface angle and dynamic loft from those readings. By their own admission, off-center hits give misleading (i.e., wrong) estimates. They say that "overall" the estimates are sound, but wouldn't you expect something more from a $30,000 device? Wouldn't you like to know if the shot that supposedly had a closed face at impact was actually a ball struck toward the heel? To learn that, every swing requires impact tape, then, after taking impact location into consideration, an educated guess at the "real" clubface angle. Who's doing that? Brian?
More importantly, Trackman can't give any information on rate of closure, so it gives no insight into the "stability" of a player's release. With the additional camera, 4dswing will do that.
Isn't clubface control supposed to be paramount to good golf? So how come a device that can't measure it is considered by Brian to be indispensable and paradigm changing? Another Anti-Summit question.
Despite these "scientific" claims, Kelvin knew that, based on his observation of "elite" players (to Kelvin, "elite" means bombers with enough control to be competitive at the highest level), body rotation did not slow down until after impact.
One piece of scientific evidence supporting Kelvin's observations was this graph from a paper by one of Brian's own experts (Sasho Mackenzie) which concluded that in an optimized swing the trunk would show increasing muscular torque through impact (applying a greater turning force), a result totally at odds with the kinetic sequence deceleration theory and those 3D "representations":
Source: Examining the delayed release in the golf swing using computer simulation, Sprigings and Mackenzie, 2002.
Despite being published nearly ten years ago, golf's "leading scientists" continue to promote the kinetic sequence theory and promote successive deceleration of the hips, shoulders and hands.
As it turns out, and as Kelvin suspected, the 3D devices that Manzella claims to be essential to understanding the golf swing measure the body all wrong. The 3D devices attach about two dozen markers on a player's body then use signals transmitted from the markers to create a "3D model". Sadly, no one bothered to actually LOOK at the real golfers and determine if the models and the golfers actually swung the same way. Turns out that they don't. Unfortunately, the 3D devices appear to measure lateral (toward the target speed), not actual speed, so, as body parts move left, they appear to slow down. Also, it appears that the devices use insufficient markers to accurately capture some critical body movements.
So, you are no doubt asking, where does this new information come from? A Finnish company named 4dswing (https://www.4dswing.com/) has developed a (hold on!) video-based system that captures images of the actual golfer (at anywhere from 100 to 500fps) from all sorts of angles, then calculates movements in 3D based on those images. (This is essentially what Kelvin and Rick Malm did on their own by filming golfers from all angles at 300fps then synchronizing the videos). The poster TeeAce works there and shared this information with Kelvin.
When the body is measured accurately using the 4dswing system, a totally different picture emerges, and one that makes far more intuitive sense than the current "science". Here is a graph that shows what is actually going on in the swing of a young, athletic, multiple winner on the European tour, that hits it and plays pretty good (top 40 driving distance, top 15 Race to Dubai).
It's a little blurry, but what this shows is that there is no sequence at all: hip speed (blue line) peaks at impact; after a brief deceleration, the shoulders (red line) accelerate through impact and peak well after; and the hands (green line) show just a modest tailing off before impact, caused by the increase in moment of inertia as the club and arms unfold. There is NO evidence of any intentional or unintentional slowing of any body part by the player, which, of course, makes perfect sense when you consider that self-taught players like JB and Gainey say that their only "intent" is to hit the ball as hard as they can. I doubt that means decelerating anything before impact.
The 4dswing product isn't ready for commercial roll-out (they plan to add a 2,000fps camera to capture the clubface through impact), so to date they have kept a low profile. Nevertheless, they are well aware that their system blows TPI and other 3D "experts" out of the water, so you'll be hearing a lot more about them in the future, I'm sure!
BTW, the additional 2,000fps camera is intended to address the major failing of Trackman: its inability to measure clubface angle and dynamic loft. Sure, the Trackman device displays a "clubface angle" and "dynamic loft" at impact, but those are not direct measurements for the simple reason that they can't be: Trackman is not capable of measuring that data.
Trackman uses radar shot down the target line, therefore it can't "see" what the clubface is doing near impact (it's not an x-ray device!). What Trackman does is take measurements of clubhead path and initial ball flight then calculates an "estimated" clubface angle and dynamic loft from those readings. By their own admission, off-center hits give misleading (i.e., wrong) estimates. They say that "overall" the estimates are sound, but wouldn't you expect something more from a $30,000 device? Wouldn't you like to know if the shot that supposedly had a closed face at impact was actually a ball struck toward the heel? To learn that, every swing requires impact tape, then, after taking impact location into consideration, an educated guess at the "real" clubface angle. Who's doing that? Brian?
More importantly, Trackman can't give any information on rate of closure, so it gives no insight into the "stability" of a player's release. With the additional camera, 4dswing will do that.
Isn't clubface control supposed to be paramount to good golf? So how come a device that can't measure it is considered by Brian to be indispensable and paradigm changing? Another Anti-Summit question.
