Post by imperfectgolfer on Feb 18, 2024 13:39:36 GMT -5
I still have no idea how Sportsbox has the ability to create 3-D data from a 2D video, but I have to accept that it may provide accurate data (according to Phil Cheetham who is the chief scientific officer for Sportsbox).
Phil Cheetham refers it to as the "magic camera" in the following video.
What worries me a lot about Sportsbox is that it is now coming out with new measurements that reflect an "ideology", which is Phil Cheetham's kinematic sequence ideology.
Here is a capture image from the video.
Phil Cheetham refers it to as the "magic camera" in the following video.
What worries me a lot about Sportsbox is that it is now coming out with new measurements that reflect an "ideology", which is Phil Cheetham's kinematic sequence ideology.
Here is a capture image from the video.
In this image, PC is trying to correlate "forces" to "motion".
I personally do not find this useful because I do not believe that it is scientifically possible to measure those forces/torques. Swing Catalyst supporters believe that their SC-GRF measurements are directly reflective of those "forces/torques, but I don't believe that it is true because they are only measuring what effect those muscular action forces have with respect to the ground (GRFs) under the feet, which do not necessarily reflect in an accurate manner what effect those muscular action forces have with respect to body motion.
PC then shows what type of measurements Sportsbox is capable of measuring.
In this capture image, note that Sportsbox is measuring biomechanical factors that it deems to be causally responsible for generating maximum clubhead speed.
Note that it is measuring the range of rotational motion of the pelvis/thorax in the backswing and the static X-factor and it even provides a score value for these measurements. Then, note that it measures the rotational speed of the pelvis, thorax, arm (presumably lead arm) and clubshaft during the downswing and gives it a score value. Then, note that it measures the pelvic drop in the early downswing and the pelvic lift in the later downswing and gives the measurements a score value. Finally, it measures factors that PC presumably believes affect the efficiency of the release of PA#2 - factors like lead wrist angle, maximum hand speed and wrist release percent - and gives it a score value.
How is it possible to allocate a score value for all those factors in a scientifically valid manner? PC states that he has developed an algorithm to show how a golfer can best maximize his speed profile score value? How is that scientifically possible?
Consider the single example that PC gives in his presentation. He noted that the maximum pelvic speed was low at 391 degrees per second. He then notes that the pelvic rotation at P4 was only 39 degrees, so he infers that the golfer will be able to generate more pelvic speed if he rotates his pelvis more clockwise during the backswing so that he has more time/pelvic travel distance to get the pelvis to speed up between P4 => P5 .
That type of thinking is unscientific!
Consider this long-drive competitor, who claims that he has driven the ball 479 yards in competition.
If you watch the video, you will note that he has an idiosyncratic way of performing his pivot motion where he deliberately avoids turning his pelvis during his backswing action. He believes that he is generating his pivot motion's rotational speed via his "slingshot" theory (using the questionable concept of myofacial bands). I have zero sympathy for his myofascial band theory, but I do agree that he could be efficiently using his abdominal oblique musculature to generate his fast rotational speed of his mid-upper torso. I noted that he does turn his pelvis first as he starts his downswing's pivot motion, but it would seem that his pivot motion's speed (and therefore lead shoulder socket speed) is mainly due to the muscular contraction of his abdominal oblique musculature. Therefore, there is no reason to believe that he will necessarily benefit by having a larger pelvic rotation during his backswing action (as PC implies).
However, things get worse with respect to PC"s unscientific pontificating when you consider the following PC image.
Note that this image shows PC's standard kinematic sequence graph where the pelvis. chest and lead arm all rotate at the same speed during the transition to the early downswing. Then, note that the pelvis reaches its peak speed first, followed sequentially by the chest and then the lead arm. PC asserts between the 14:30 - 15:20 minute time point of the video that energy is being transferred from one segment to the next segment in the kinematic sequence creating a "speed gain" phenomenon and he has even posted specific numbers as reference values for each segment's rotational speed that he believes will enable a golf instructor to determine if there is a deficiency in the contribution of each segment (pelvis, chest, lead arm, lead wrist) to the potential maximum speed profile.
I think that PC's opinions are unscientific and only reflective of PC's biased opinions on how a pro golfer could potentially generate his maximum clubhead speed at impact.
Here are PC's graphs showing the kinematic sequence of many pro golfers.
Note the huge degree of variation.
For example, note that Zach Johnson's pelvic speed reaches its maximum speed last, and well after his lead arm reaches its maximum speed.
For example, note that Jim Furyk's lead arm speed reaches its maximum speed before his chest reaches its maximum speed.
For example, note that Rickie Fowler's lead arm is speeding up disproportionately fast relative to the rotational speed of his pelvis and chest during his early downswing and it reaches its maximum speed at the same time as his pelvis reaches its maximum rotational speed and before his chest reaches its maximum rotational speed.
For example, note that Rory McIlroy's chest rotational speed reaches its maximum speed at the same time as his pelvis reaches its maximum rotational speed.
For example, note that JB Holmes can generate the highest clubshaft speed at impact - even though his pelvis/chest/lead arm speeds are much slower than either Rickie Fowler's or Rory McIlroy's.
Consider Jon Rahm's kinematic sequence graph.
Note that his lead arm graph (blue graph) starts to speed-up very fast during his early downswing, and that it is traveling much faster than his pelvis/chest during his early downswing between P4 => P5 - well before it can theoretically gain energy from the rotation of his pelvis/chest.
I think that it is irrational to assert that his kinematic sequence is disordered because his lead arm is traveling so fast during his early downswing time period.
I think that uninformed golf instructors, who use Sportsbox, and get this type of biased "speed profile" information from Sportsbox will not have the insight to interpret the data correctly, and that they will be potentially induced to try to get every one of their student-golfers to swing like PC's standard kinematic sequence graph.
Phew!
Jeff.