Thinking about the value of Swing Catalyst GRF measurements

[imperfectgolfer]

Part 1-:



In this post I am going to summarise my present-day opinions regarding the utility of Swing Catalyst GRF measurements.

I am not a golf instructor, who teaches student-golfers using technological devices like the Swing Catalyst device or a Hack Motion device. I am only an amateur golf theorist who tries to better understand the golf swing biomechanics/mechanics performed by pro golfers. Even though I have no practical experience using a Swing Catalyst device, I am mentally capable of analysing the data obtained from a Swing Catalyst device and I am also mentally capable of analysing whether the acquired ground reaction force (GRF) data can be useful from a golf instructional perspective. In another thread, Jim George suggested that my personal opinions have no merit because I have no practical experience using a Swing Catalyst device, but I strongly believe that my personal opinions have merit if I thoroughly evaluate the "evidence" provided by golf instructors who do use a Swing Catalyst device.

This post will only be understandable if a reader has sufficient background knowledge of what measurements are being made by a Swing Catalyst device, and uninformed readers should at least view this video presentation by Scott Lynn if they do not have the requisite background knowledge.

Here is what an "average" pro quality SC trace would look like - featuring Justin Rose's SC measurements.

The magenta-colored graph is a measure of his horizontal GRF and it usually peaks first at P3.5 - P4.5. The positive horizontal GRF measurement is usually due to pushing off the trail foot in a targetwards direction and the negative measurement is due to the golfer pushing off his lead foot in an away-from-the-target direction.

The yellow-colored graph is a measure of his rotary torque GRF and it usually peaks slightly later between P4.5 - P5.

The cyan-colored graph is a measure of his vertical GRF graph and it usually peaks between P5 - P5.5. Note that there is a very good correlation between the timing of the peak of the vertical GRF and the peak of the negative horizontal GRF, which makes sense from a biomechanical perspective. A golfer can use the negative horizontal GRF to "brake" the targetwards motion of the pelvis so that he can avoid excessive pelvic sway in the targetwards direction and it also allows him to more efficiently direct the lead side of the pelvis to move backwards away from the ball-target line (in the direction of the tush line) when the lead leg straightens between P5.5 => P7.

The black strip zone in the background represents the PGA tour averages and JR reaches into that zone with respect to all of his GRFs and he represents what Scott Lynn calls a "Trifecta".

I do not dispute that this "Trifecta" pattern is often seen in skilled amateur and pro golfers, and I only dispute that it is a necessary requirement for performing a pro-quality driver golf swing action. I fully agree that a golfer has to generate GRFs when performing a full golf swing action and it is impossible to perform a full golf swing action in an efficient manner when standing on an ice rink. However, I question whether there is any direct correlation between a "Trifecta" pattern of GRFs and a good quality golf swing action as judged from the perspective of a golfer's overall golf swing biomechanics and, most importantly, in terms of a golfer's ability to consistently hit the ball straight towards his intended target. I do not dispute an opinion that optimising the GRFs forces so as to better mimic the "Trifecta" pattern can potentially increase the maximum clubhead speed measured at impact in a driver swing by approximately 5 - 10mph in a subset of skilled golfers - but that does not mean that their golf swing's biomechanical motions are optimum.

Here are a few examples of pro golfers who do not manifest the "Trifecta" pattern, but who can still drive the ball a long distance (~300 yards) when playing on the PGA tour.

Here is Charles Howell III's SC measurements - measured when his rotary torque GRF peaks at P5. 

Note that CH III has the typical pattern of GRF generation where the horizontal GRF peaks first, followed by the sequential peaking of the rotary torque GRF and then the vertical GRF.

However, note that the magnitude of his rotary torque GRF is very small and yet he is fully capable of driving the golf ball >300 yards.

Here are capture images of his downswing action.

Image 1 is at P4, image 2 is at P5 and image 3 is at P5.5.

Note that CH III manifests a rightwards pelvic loading pattern and a borderline rightwards/vertical centralised upper torso loading pattern by P4. Note that I have drawn red lines alongside the outer border of his pelvis at his P4 position.

Note that CH III manifests a lot of pelvic shift motion in a targetwards direction between P4 => P5.5 and it is therefore understandable why he generates a large magnitude horizontal GRF at the start of his transition to the downswing in order to efficiently perform that pattern of pelvic shift motion. It is also understandable why he needs to generate a large vertical GRF peaking at ~P5.5 in order to allow him to generate a large negative horizontal GRF that is needed to "brake" the targetswards motion of his pelvis.

However, he obviously does not need to generate a large rotary torque GRF (peaking at ~P5) in order to perform a good rotary motion of his pelvis and upper torso during his downswing action. This SC measurement was made many years ago and his coach (Dana Dahlquist) has apparently worked with CH III in order to change his SC measurement pattern. I have not seen his latest SC measurements to determine whether he is generating a larger rotary torque GRF and I also have no evidence that he is driving the ball further and straighter as a result of any changes in his SC measurement pattern. If you have any "evidence", then I would be very interested in analysing that "evidence".

Here is Boo Weekley's SC measurements. 

Note that BW generates a very small horizontal GRF and a very small vertical GRF in his driver golf swing action, and yet he can drive the golf ball ~280 - 290 yards.

Here are capture images of his driver's downswing action.

Image 1 is at P4, image 2 is at P5, image 3 is at P6 and image 4 is at P7.5.

Note that BW uses a centralised pelvic loading pattern and a borderline rightwards-centralised upper torso loading pattern.

Note that BW squares his pelvis between P4 => P5 without swaying his pelvis targetwards and that makes it understandable why he is using a large amount of rotary torque GRF with very little preliminary horizontal GRF between P4 => P5. Also, note that his rotary torque graph starts increasing before his horizontal GRF graph.

Note that BW stalls the rotary motion of his pelvis at ~P5.5 and he does not actively continue to rotate his pelvis between P5.5 => P7.5. Therefore, it is possible that he does not need to generate any significant amount of vertical GRF to move his lead buttock back away from the ball-target line, and also away from the target, between P5.5 => P7. There is also no visual evidence that he is a "jumper " (who uses a launcher pattern requiring a large vertical GRF) through impact and both of his feet seem to be solidly grounded through impact. Even if one does not like his golf swing's torso motional pattern, it seemingly works very well for him and I would like to see any person explain why BW would perform his golf swing action better by significantly increasing either his horizontal GRF between P4 => P4.5 or his vertical GRF between P5 => P6.

Here is Gary Woodland's SC measurements.

Note that GW manifests the standard kinetic sequence of GRFs where the horizontal GRF peaks first, followed by the peaking of the rotary torque GRF, and then followed by the peaking of the vertical GRF.

However, note that GW generates a very small magnitude of vertical GRF and yet he is still one of the longest drivers on the PGA tour. I know of no reason to believe that GW would benefit by increasing the magnitude of his vertical GRF so that it reaches PGA tour levels (black zone) and I can identify no flaws in his driver golf swing torso's motion that are reflective of a deficit in the magnitude of his vertical GRF generation. If any person has an alternative opinion, feel free to express that opinion in a post.

Here is Matt Kuchar's SC measurements. 

According to Scott Lynn, MK is the only pro golfer he has seen who has a disordered kinetic GRF sequence where the rotary torque GRF peaks before the horizontal GRF. Also, note the small magnitude of the vertical GRF graph. I am not personally surprised to note these GRF measurements because MK is a prototypical example of a Jim Hardy one-plane swing golfer.

After seeing these SC measurements, a golf instructor (? Mike Adams or Terry Rowles) worked with MK to improve his GRF measurements and obtained the following results.

Note that these SC graphs show the standard kinetic GRF sequence where the horizontal GRF peaks before the rotary torque GRF.

Do these changes represent an improvement? According to Mike Adams they do because MK's clubhead speed at impact went up by ? 5 - 10 mph.

However, when using this "altered" golf swing GRF-pattern MK started to hit too many balls left in his golf practice sessions so he stopped using that pattern, and he went back to his original GRF-pattern. This example demonstrates the weakness of the Mike Adams golf instructional approach (based on SC measurements) where he focuses his primary attention on maximising clubhead speed. I have viewed a number of videos where Mike Adams marginally increased a golfer's maximum clubhead speed at impact by 5 - 10mph, but I saw nothing to suggest that it improved the golfer's overall golf swing biomechanics in such a manner that it would improve his ability to consistently hit the ball straighter.

Consider an example how a golf instructor could use SC measurements to alter a golfer's golf swing action.

Watch the following video between the 56:40 - 1:06:31 minute time points.

SL is working with an amateur golfer, who he calls "Harrison".

Here is Harrison's SC measurements when using a 7-iron.

Note that he has the standard GRF kinetic pattern.

Scott Lynn noted that his clubhead path was too much in-to-out (6.9 degrees) at impact. He also stated that Harrison's rotary torque GRF measurement was below the tour average while his horizontal GRF was in the tour zone. SL then hypothesised that too much horizontal GRF combined with too little rotary torque GRF is causally responsible for Harrison's excessively in-to-out clubhead path. I can partly understand the logic of SL's reasoning considering the height of this golfer and how narrow his stance is in the face of too much horizontal GRF generation, and I can easily imagine this golfer being susceptible to too much pelvic sway motion at the start of his downswing that can predispose to an excessive in-to-out clubhead path pre-impact. Interestingly, SL did not demonstrate that this golfer has too much left-lateral pelvic sway motion during the early-mid downswing and he did nothing to get this golfer to decrease his horizontal GRF generation. Instead, SL decided to work on increasing Harrison's rotary torque GRF. SL first got the golfer to swing using the "one-leg swing test" to determine which is his dominant (stronger) leg. I personally think that the test is irrational if a golfer uses a TGM swinging action where low point is located below the lead shoulder socket - because it is much easier to swing better off the lead leg than the trail leg when performing a TGM swinging action. Also, this one-leg technique encourages an artificial upper body-powered golf swing action, which is not what many skilled golfers would normally use in their "real life" golf swing action. SL decided, based on the one-leg swing test, that Harrison's lead leg is his dominant leg and he therefore decided to work on his lead leg's ability to generate a horizontal GRF. SL used the training drill technique, which he calls reactive neuromuscular training, where the golf instructor uses an elasticised rubber band - see the 1:01:25 - 1:02:25 minute time point of the video. The purpose of the drill is to get the golfer to push against the ground with his lead foot in a "towards the ball-target line" direction, which theoretically should cause the lead pelvis to move back towards the tush line. After performing the drill, there was negligible improvement in his excessive in-to-out clubhead path swing fault (which was 5.9 degrees at the end of the drill training session) and an insignificant change in his clubhead speed (which was not really a problem that even needed to be addressed because he was generating an excellent clubhead speed of 93 mph with a 7-iron).

Here is another video where Scott Lynn measures the GRFs of the amateur long-hitter - Drew Cooper - and then attempts to modify his GRF pattern with the goal of increasing his driver clubhead speed at impact.

Here is a capture image of Drew's Swing Catalyst measurements.

Note that Drew can achieve GRFs that exceed the black zone (tour average zone) with respect to all of those GRFs and that his vertical GRF is 239% of his body weight.

Drew wants to increase his clubhead speed at impact from 140mph to a larger value.

Even though he already has a very high vertical GRF, Scott suggests that he try to increase his vertical GRF, which peaks in his early downswing. However, that idea does not work-out to be beneficial because it causes Drew to *"feel" that his upper body is "falling back" (away from the target) which causes Drew's clubhead speed to then decrease. Drew mentions that he wants to stay centered during his downswing action and avoid any "hanging-back" phenomenon involving his upper torso. Scott then suggests that he needs to strengthen the abdominal muscles on the left side of his abdomen so that he can increase his vertical GRF even more without having to experience a "falling back" phenomenon of his upper torso. Scott believes that if Drew can increase his vertical GRF more while avoiding any tendency for his upper torso to "fall-back", that the increased vertical GRF would translate into a faster clubhead speed at impact. Why should it? How can an increased vertical GRF measurement at ~P5.5 increase clubhead speed?

(* To understand why increasing the vertical GRF under the lead foot in the early downswing can theoretically cause the upper body to be predisposed to rotate counterclockwise around the body's COM, watch the following AMG video - www.youtube.com/watch?v=e82g4YuXv1Y&t=566s - between the 13:20 - 15:20 minute time points).

Here are capture images of Drew's downswing action.

Image 1 is at P4, image 2 is at P4.5, image 3 is at P5, image 4 is at P5.5, image 5 is at impact and image 6 is at P7.4.

Note that I have drawn blue lines alongside his head and red lines alongside the outer border of his pelvis at his P4 position.

Note that Drew has a centralised pelvic loading pattern and a borderline rightwards-centralised upper torso loading pattern during his backswing action that ends at P4.

Note that Drew starts his downswing with a re-centering phenomenon where his upper and lower swing centers slide targetwards between P4 => P5 while he is simultaneously squatting and performing a hip-squaring action where he rotates his pelvis counterclockwise to become square by P5.

Note that Drew has achieved his peak vertical GRF by P5.5 (image 4) and that is also when his lead arm speed has probably reached its maximum speed due to his pivot-induced release of PA#4. Note that he has successfully "braked" his lead pelvis's targetwards slide by P5.5 and he is successfully avoiding any "fall-back" of his upper body. So, how could increasing his vertical GRF at P5.5 increase his clubhead speed? I can see no deficit in his golf swing biomechanics that would cause him to release PA#4 with sub-maximum efficiency between P4 => P5.5 and to cause him to release PA#2 with sub-maximum efficiency between P5.5 => P7. Note how efficiently he elevates his lead shoulder socket between P5 => P7 due to a very well-executed lead leg straightening action, which is simultaneously combined with a stretching-out phenomenon of the left side of his mid-upper torso, so he is presumably maximising the centripetal component of his MoF torque that is causally responsible for providing the torque-force needed to efficiently release PA#2.

Scott's suggestion that Drew needs to strengthen his left-sided abdominal wall muscles makes no sense to me. I can see no evidence of Drew's upper torso falling back during the swing power phase causing the release of PA#4 between P4 => P5.5. Also, Scott's claim that an increasing vertical GRF will invariably cause a counterclockwise rotation of the upper torso (in an away from the target direction) because the vertical GRF vector is closer to the target than the body's COM is not necessarily applicable to Drew's driver golf swing action - although it may be applicable to the driver golf swing action of many pro golfers.

Here is a capture image showing Drew's vertical GRF vector/magnitude when he is at his ~P5.4 position when his vertical GRF has reached its peak value.

Note that his lead foot's resultant GRF (blue arrow) is large and mainly responsible for the magnitude of his overall GRF (green arrow). Note that both of those GRF arrow vectors are angled away from the target and they are both behind his body's COM, which has shifted a lot targetwards between P4 => P5.5 due to his re-centering phenomenon. That means that his upper torso is theoretically being subjected to a clockwise rotation around his imaginary COM, which should actually prevent a "falling-back" phenomenon of his upper torso. Therefore, Scott's theory about the relationship between the vertical GRF and a "falling-back" phenomenon of the upper torso may not be valid with respect to Drew's driver golf swing action.

I personally think that Scott's "theories" about the effect of a large vertical GRF on Drew's golf swing biomechanics and its effect on Drew's ability to increase his clubhead speed at impact has no merit - because I think that there is no direct causal connection between the vertical GRF that is measured at the level where the feet interact with the ground and the efficiency of a golfer's golf swing biomechanics that is causally responsible for causing the release of PA#4 => PA#2 with maximum efficiency.

I will now present another very dramatic example of Scott Lynn teaching a golfer that I think clearly shows the futility of only focusing on GRF measurements to improve a golfer's golf swing action.

This video was made at a level 2 workshop in Luxembourg where Scott Lynn is teaching a student golfer (Yann) using a Swing Catalyst device.

Here is Yann's Swing Catalyst measurements at the start of teaching session when he was swinging a mid-iron at a clubhead speed of 96mph at impact.

Note that he has a good kinetic GRF sequence where the horizontal GRF peaks first, followed by peaking of the rotary torque GRF and then followed finally by the peaking of the vertical GRF. Note that he generates a very high horizontal GRF and vertical GRF that is well within the tour average range even though he is only swinging an iron and not a driver. Note that his rotary torque measurement is just below the tour average range. He is very close to manifesting a perfect "Trifecta" pattern - as defined by Scott Lynn.

Scott Lynn (SL) starts off his presentation between the 0:00 - 1:02 minute time point of the video by asking a fundamental question - based on Yann's SC-measurements should one make him a rear post golfer who will then need to create more horizontal GRF in order to swing faster, or should he get Yann to become a front post golfer who will then need to increase his vertical GRF in order to swing faster, or should he make Yann a center post golfer who will then need to increase his rotary GRF in order to swing faster.

SL then decides to use two tests to determine Yann's leg dominance pattern. The first test is the one-leg swing test (which I have previously mentioned) and which happens between the 1:20 - 2:00 minute time points of the video. Watch Yann swing and you will note that he is actually using an active upper body rotary motion to power his golf swing action, and he is not really using his pelvis/legs to power his golf swing. So, how one can reasonably think that this single-leg swinging test can possibly determine whether one will perform a better golf swing action as a rear post, center post or front post golfer? SL concludes, based on that swing test, that Yann's test results are intermediate between a front post and a center post golfer.

SL then gets Yann to perform another test to determine leg dominance - watch the video between the 3:08 - 3:48 minute time points of the video. That's a strange test that only tests whether a golfer can maintain his balance when rotating 90 degrees by leaning to one side or the other side, and I cannot fathom how it can determine whether a golfer will perform a full golf swing action more efficiently as a rear post, center post or front post golfer.

SL concludes, based on Yann's leg dominance testing performance, that Yann should use a center post technique and that he should increase his rotary torque GRF by performing SL's reactive neuromuscular training drills - see the 6:08 - 8:08 minute time point of the video. Note that the supposedly true purpose of the training drill is to get Yann to rotate his pelvis better during the downswing so that his pelvis can be more open at impact. Interestingly, SL makes a comment during the drill where he states that Yann's chest is rotating better! That is a very important point - because if you look carefully at Yann's performance during the drill, one can see that he is actively rotating his upper torso when the true purpose of the drill is to get the lead leg to push more forcefully away from the ball-target line in the direction of the tush line in order to actively improve one's counterclockwise pelvic rotation between P5 => P7.

After performing the reactive neuromuscular training drill session, Yann performs his golf swing action and SL is happy with the results because Yann has decreased his horizontal GRF to a small degree, but he has significantly increased his rotary torque GRF measurement. Most importantly, note that SL does not mention whether Yann's increased rotary torque GRF measurement translates to a better pelvic rotation where he can reach impact with a more open pelvic alignment (eg. 45 degrees open at impact).

So, let's look more closely at Yann's golf swing action that was recorded at the end of the video.

This capture image shows Yann at his P4 position where his horizontal GRF is at its peak value (which is still very high and near the top of the tour average range).

Note that Yann is using an arch-extension maneuver to arch his upper thoracic spine more towards the target - based on SL's advice. Why SL would recommend an arch-extension maneuver for a center-post golfer is inexplicable from my perspective!

Note that I have drawn red lines along the back of his trail buttock (and that represents the tush line) and also alongside the outer border of his pelvis.

This capture image is when Yann's rotary torque GRF measurement reaches its peak value and it is just below the black zone (tour average zone).

Note that Yann's rotary torque force peaks before one sees any significant amount of pelvic rotation - and that is fully expected because force should theoretically always precede motion. However, note that he is actively rotating his upper torso counterclockwise, which can be causally responsible for increasing the rotary torque GRF measurement (as described later).

This capture image is when Yann's vertical GRF reaches its peak value - which is early, happening at the P5 position.

Note that Yann has successfully completed his hip-squaring action by P5 (as seen on the DTL view). However, look at his face-on view capture image which shows how much he has swayed his pelvis targetwards by P5 where the outer border of his pelvis is outside a vertical line drawn upwards from the outer border of his left foot. He is supposed to be a center post golfer who should manifest the "Sam Snead sit-down look" at P5 - where the pelvis remains centered between the two feet and where there is symmetrical dual external rotation of both femurs in their respective hip joints. Instead, he manifests far too much left-lateral pelvic sway motion - despite the fact that he is generating a very large vertical GRF and simultaneously generating a very large negative horizontal GRF (large horizontal braking force) at P5.

Also, note how steeply his clubshaft is coming down the swingplane with no clubshaft shallowing action. 

This capture image is at impact.

Note that he has not rotated his pelvis significantly more counterclockwise in his later downswing between P5 => P7 and his pelvis is only borderline open at impact - despite trying to improve his pelvic rotary torque action by performing SL's reactive neuromuscular training drill. His rotary torque GRF graph has increased slightly and reached the lower limits of the black zone (tour average zone) but it has not translated into a better rotary motion of his pelvis between P5.5 => P7.

Also, note that he has lost his spinal bend inclination angle and that he is "standing-up" through impact with both buttocks moving away from the tush line. I believe that it is due to the combination of too much pelvic slide motion combined with an inadequate amount of pelvic rotary motion.

Note that his upper torso is parallel to the ball-target line, and that it is not open to the ball-target line at impact (as can be seen in his reactive neuromuscular training drill action).

Note that he has a very sub-optimum hand release action through impact where he is stalling the targetwards motion of his lead arm and fully straightening his trail arm and trail wrist in a slap-hinge manner through impact - thereby resulting in a gross example of a flipping sub-type of non-DH hand release action through impact.

Here are capture images of one of his full swings that he performs at the end of the video.

Image 1 is at P4, image 2 is at P4.5, image 3 is at P5 and image 4 is at impact.

Note that he has completed the hip-squaring action by P5, but his lead hip joint is higher than his trail hip joint as a result of his excessive pelvic slide motion.

Note how steeply his clubshaft comes down the swingplane and there is no clubshaft shallowing action happening between P4 => P6 - which is not surprising considering the fact that he does get any right lateral bend that can drop his trail shoulder lower in a ferris-wheel manner during his later downswing and he also does not perform an active trail upper arm adduction maneuver that is combined with a pitch elbow motion of his trail elbow.

Note that his pelvis is barely open at impact and that his shoulders are square to the ball-target line at impact. Note that he is not moving his lead shoulder up-and-inside/left during his later downswing as a result of a counterclockwise rotation of his pelvis/upper torso and note that he is stalling his lead arm and slapping at the ball with his trail arm/hand at impact.

I personally think that Yann has a very sub-optimum golf swing action despite manifesting an excellent "Trifecta" pattern of GRF generation. This example shows that there is no direct/positive correlation between excellent GRF measurements obtained by a Swing Catalyst device and good quality golf swing biomechanical motions, and I think that by only concentrating on getting Yann to generate a larger rotary torque GRF measurement during his early downswing that SL has done nothing usefully productive to improve Yann's golf swing biomechanical motions.

Finally, here is a very important fact that golf instructors, who use the Swing Catalyst device, do not seemingly even factor-in into the rotary torque GRF-generation equation.

Watch the following Swing Catalyst video.

Watch the video starting at the 14 minute time point when the Swing Catalyst Ambassador-Presenter starts to talk about the concept of rotary GRF generation. He instructs the volunteer to perform a 360 degrees jump-rotation action and he measures the amount of rotary torque GRF being generated under her feet.

This is the result.

Note that she generates a rotary torque GRF measurement of 33FF/9.6 lbs/foot.

The Swing Catalyst Ambassador-Presenter is obviously not happy with the magnitude of her rotary torque GRF measurement and he instructs her to repeat the 360 degrees jump-rotation action as before, but he instructs her to deliberately spin her shoulders more actively during her 360 degree jump-rotation action by "throwing her arms around" to create more rotary torque.

Here is the result.

Note that she generates a rotary torque GRF measurement of 84FF/23 lbs/foot.

That is nearly 3X the amount of rotary torque GRF generation - and it is the direct result of an active upper torso rotary motion.

In other words, a golfer can theoretically generate far more rotary torque GRF in the early downswing if he adds additional rotary force due to an active upper body rotary maneuver. That means that an upper body swinger can potentially generate a much greater magnitude of rotary torque GRF generation between P4 => P5 than a lower body swinger. However, that will likely result in an OTT move and possibly an out-to-in clubhead path through impact if the pelvis is totally static/passive. If the pelvis is partially active in terms of its rotary motion, the simultaneous addition of more active rotary torque derived from an active upper torso rotation can potentially produce an extremely large rotary torque GRF measurement at ~P4.5, which can be well within the black zone (tour average zone), but very little of that rotary torque GRF measurement will be due to an active leg action (where the trail foot pushes away from the ball-target line while the lead foot pushes towards from the ball-target line).

I strongly suspect that Yann is generating most of his rotary torque GRF measurement, which peaks at P4.5, due an active upper torso rotary action and that he is not actively using his legs to generate any rotary torque GRF during his early downswing. That could partly explain why he had such an ineffective pelvic rotary motion during his downswing action that was performed under the golf instructional supervision of Scott Lynn!

Jeff.

[dubiousgolfer]

Dr Mann - another great analysis .

As you've shown above, there are different movement patterns that a golfer could do which can affect Swing Catalyst graphs. Some of those movements might recreate a theorised optimal set of graphs while the result could be an awful golf swing.

I suspect it would be better to do a combined analysis, maybe using 3D and Force/Pressure plates  and then conduct comparisons with what low handicap/Tour Pros might be doing.

DG

[dubiousgolfer]

Dr Mann

One small issue concerning this image below.



You said
"Note that his lead foot's vertical GRF (blue arrow) is large and mainly responsible for the magnitude of his overall vertical GRF (green arrow)"

The blue and red arrows are the individual resultant GRF forces from the lead and trail feet, while the green arrow is the net force from the COP position (ie. the vector sum of both blue and red vectors).

These vectors are not 'vertical' grfs, which, for the sake of accuracy, would be the vertical components of these blue/red/green vectors.

DG

[imperfectgolfer]

Mar 30, 2023 10:48:02 GMT -5 dubiousgolfer said:

Dr Mann

One small issue concerning this image below.



You said
"Note that his lead foot's vertical GRF (blue arrow) is large and mainly responsible for the magnitude of his overall vertical GRF (green arrow)"

The blue and red arrows are the individual resultant GRF forces from the lead and trail feet, while the green arrow is the net force from the COP position (ie. the vector sum of both blue and red vectors).

These vectors are not 'vertical' grfs, which, for the sake of accuracy, would be the vertical components of these blue/red/green vectors.

DG

You are correct.

The height of the arrow is determined by the vertical GRF while the angulation of the arrow is affected by the other GRFs.

I edited my original post.

Jeff.

[playing18]

Dr. Mann,

I would never suggest your opinions on the golf swing have no merit, but your analysis of Swing Catalyst is not about golf swing mechanics. This current thread illustrates the same problem that I mentioned before. I see no short- or long-term golf performance output data to back up your opinions.  

Show me a PGA pro, a golf instructor, or really any golfer who follows the Swing Catalyst results blindly, and I'll show you a golfer or instructor who is confused and focusing on the wrong thing. No informed person is going to attempt to "change" or "improve" any SC data unless it results in better short- and long-term ball flights and lower golf scores. As always, let the dog wag the tail.

This is no different than taking a lesson from a PGA golf instructor. Is the golf instruction more important than the golf performance that follows? Should a golfer simply say: this is what the pro told me to do, and even though I score terribly after weeks of playing, I'm going to keep trying to swing correctly. Is swinging "correctly" more important than having fun and playing one's best? I don't think so.

Matt Kuchar made an informed choice based on his on-course golf performance and not on his SC data. He elected to ignore Scott Lynn's advice, and based on his PGA tournament record, he probably made the right choice. Not a hard decision when MK is informed and focusing on the right thing. Was Scott Lynn wrong in suggesting a possible correction? Of course not. The player is the ultimate decision maker and SL simply made a logical recommendation based on atypical GRF data.

Most PGA pros would/should do the same as MK. Why change your swing when it has proven to be PGA-tour worthy? However, there may still be some rare exceptions. Perhaps a player like Luke Donald was taught to do something that wasn't truly the best for him. It's possible. So he takes the advice of an instructor (Mike Adams) to adjust his GRF profile to see if this helps. He implements the changes and it works. He sees both short- and long-term improvements in his golf performance. Did the SC profile help this golfer? Yes. Should the golfer change his swing and GRF profile if it doesn't lead to improvement in on-course performance? Of course not.

The same applies to Justin Rose, Charles Howell, Boo Weekley, and Gary Woodland. It has nothing to do with the SC data, and everything to do with on-course golf performance.

What about the player who has obvious swing errors yet has a normal GRF profile? Well, this is still probably better than having a poor GRF profile, and it shows the player is doing something correctly. Does this mean that the SC data are displaying a false positive? I don't think so. Does it mean the GRF profile will improve somehow when the swing error is corrected? Maybe or maybe not. However, it is of no consequence. All that matters is on-course golf performance. 

But, I assume most players can get a specific baseline GRF force-print when they are hitting the ball at their best and a slightly different one when they are hitting the ball poorly. To me, this is what makes SC a potentially good feedback tool. This way the player can work on swing mechanics that bring back the "good" hitting GRF profile as fast as possible and see if it solves the on-course swinging problem. And, this will likely make it easier and faster to correct similar swing mechanic issues in the future. But, if the SC data doesn't help a given player in this process, so be it. They can find other feedback tools to help them. But, most likely SC will provide enough players enough useful guidance to justify its use. If so, it will grow in popularity. If not, it will fade out of existence. Time will tell.

I was watching a YouTube video recently where the commentator was showing Jim Furyk's swing, and said "here is Jim Furyk's swing which no instructor would ever teach to another golfer". And, I wondered, why not? If it works for JF, why can't it work for other players? It certainly could and it all depends on what happens on the golf course. If it works, then do it. If not, then try something else. But, the idea that there is an ideal swing is no different than thinking that the SC data are all that matter. The ideal PGA tour pro swing model is no more important than the ideal SC profile. Both provide possible solutions for what might work for a given player out on the golf course, but there are no guarantees. 

David Leadbetter worked with Lydia Ko for a period of time and he reportedly recommended swing changes to this elite player. In hindsight, it doesn't appear that DL did a very good job with her and probably did more harm than good. How did this happen? Easy answer: Lydia Ko didn't focus enough on golf performance and placed too much trust in an expert authority. She was young and determined to get even better. She was also probably uninformed and too trusting. She needed more short-term golf performance data to guide her. Maybe Swing Catalyst data could have helped her had it been available. Perhaps the swing changes DL recommended could have been compared to LK's baseline GRF data when she was swinging at her best. It may have provided immediate feedback that these recommended swing changes were not helpful, and especially in comparison with Trackman data and on-course performance/scoring data. Unfortunately, this did not happen and Lydia was in a slump for years.

On the other hand, what if a given player has an obvious swing error (OTT move, early extension) but it is the best they can do and they actually hit the ball worse after attempting to correct it? Should this person keep trying to emulate the perfect PGA swing model or perfect SC profile to their detriment. Not in a sane world. There is only one thing that ultimately matters to the informed player: on-course golfing performance and on-course enjoyment. 


Jim - playing18

[imperfectgolfer]

Mar 30, 2023 15:24:05 GMT -5 playing18 said:

Dr. Mann,

I would never suggest your opinions on the golf swing have no merit, but your analysis of Sports Catalyst is not about golf swing mechanics. This current thread illustrates the same problem that I mentioned before. I see no short- or long-term golf performance output data to back up your opinions.  

Show me a PGA pro, a golf instructor, or really any golfer who follows the Swing Catalyst results blindly, and I'll show you a golfer or instructor who is confused and focusing on the wrong thing. No informed person is going to attempt to "change" or "improve" any SC data unless it results in better short- and long-term ball flights and lower golf scores. As always, let the dog wag the tail.

This is no different than taking a lesson from a PGA golf instructor. Is the golf instruction more important than the golf performance that follows? Should a golfer simply say: this is what the pro told me to do, and even though I score terribly after weeks of playing, I'm going to keep trying to swing correctly. Is swinging "correctly" more important than having fun and playing one's best? I don't think so.

Matt Kuchar made an informed choice based on his on-course golf performance and not on his SC data. He elected to ignore Scott Lynn's advice, and based on his PGA tournament record, he probably made the right choice. Not a hard decision when MK is informed and focusing on the right thing. Was Scott Lynn wrong in suggesting a possible correction? Of course not. The player is the ultimate decision maker and SL simply made a logical recommendation based on atypical GRF data.

Most PGA pros would/should do the same as MK. Why change your swing when it has proven to be PGA-tour worthy? However, there may still be some rare exceptions. Perhaps a player like Luke Donald was taught to do something that wasn't truly the best for him. It's possible. So he takes the advice of an instructor (Mike Adams) to adjust his GRF profile to see if this helps. He implements the changes and it works. He sees both short- and long-term improvements in his golf performance. Did the SC profile help this golfer? Yes. Should the golfer change his swing and GRF profile if it doesn't lead to improvement in on-course performance? Of course not.

The same applies to Justin Rose, Charles Howell, Boo Weekley, and Gary Woodland. It has nothing to do with the SC data, and everything to do with on-course golf performance.

What about the player who has obvious swing errors yet has a normal GRF profile? Well, this is still probably better than having a poor GRF profile, and it shows the player is doing something correctly. Does this mean that the SC data are displaying a false positive? I don't think so. Does it mean the GRF profile will improve somehow when the swing error is corrected? Maybe or maybe not. However, it is of no consequence. All that matters is on-course golf performance. 

But, I assume most players can get a specific baseline GRF force-print when they are hitting the ball at their best and a slightly different one when they are hitting the ball poorly. To me, this is what makes SC a potentially good feedback tool. This way the player can work on swing mechanics that bring back the "good" hitting GRF profile as fast as possible and see if it solves the on-course swinging problem. And, this will likely make it easier and faster to correct similar swing mechanic issues in the future. But, if the SC data doesn't help a given player in this process, so be it. They can find other feedback tools to help them. But, most likely SC will provide enough players enough useful guidance to justify its use. If so, it will grow in popularity. If not, it will fade out of existence. Time will tell.

I was watching a YouTube video recently where the commentator was showing Jim Furyk's swing, and said "here is Jim Furyk's swing which no instructor would ever teach to another golfer". And, I wondered, why not? If it works for JF, why can't it work for other players? It certainly could and it all depends on what happens on the golf course. If it works, then do it. If not, then try something else. But, the idea that there is an ideal swing is no different than thinking that the SC data are all that matter. The ideal PGA tour pro swing model is no more important than the ideal SC profile. Both provide possible solutions for what might work for a given player out on the golf course, but there are no guarantees. 

David Leadbetter worked with Lydia Ko for a period of time and he reportedly recommended swing changes to this elite player. In hindsight, it doesn't appear that DL did a very good job with her and probably did more harm than good. How did this happen? Easy answer: Lydia Ko didn't focus enough on golf performance and placed too much trust in an expert authority. She was young and determined to get even better. She was also probably uninformed and too trusting. She needed more short-term golf performance data to guide her. Maybe Swing Catalyst data could have helped her had it been available. Perhaps the swing changes DL recommended could have been compared to LK's baseline GRF data when she was swinging at her best. It may have provided immediate feedback that these recommended swing changes were not helpful, and especially in comparison with Trackman data and on-course performance/scoring data. Unfortunately, this did not happen and Lydia was in a slump for years.

On the other hand, what if a given player has an obvious swing error (OTT move, early extension) but it is the best they can do and they actually hit the ball worse after attempting to correct it? Should this person keep trying to emulate the perfect PGA swing model or perfect SC profile to their detriment. Not in a sane world. There is only one thing that ultimately matters to the informed player: on-course golfing performance and on-course enjoyment. 


Jim - playing18

I totally disagree with many of your opinions.

You wrote-: "Show me a PGA pro, a golf instructor, or really any golfer who follows the Swing Catalyst results blindly, and I'll show you a golfer or instructor who is confused and focusing on the wrong thing. No informed person is going to attempt to "change" or "improve" any SC data unless it results in better short- and long-term ball flights and lower golf scores. As always, let the dog wag the tail."

I think that Scott Lynn, and his golf students, are too focused on SC measurements and not on the soundness of their basic golf swing biomechanics and their ultimate ball striking performance.

I have already given one example - featuring that golfer called Yann. SC only focused on improving his rotary torque GRF without establishing that it actually improved his pelvic rotary motion or his ball flight accuracy.

Here is another example featuring Scott Lynn.

SL again tried to improve this golfer's golf swing action solely based on SC measurements and he wanted to get the golfer to increase his rotary torque GRF measurement. At the end of the session, the golfer was far more out-of-control and hitting the ball too far leftwards (to a degree that made SL laugh).

When I looked at the gross amount of flipping action in his gross flipping subtype of non-DH hand release action, I am not surprised. I personally think that it is waste of time/effort to perform a SC measurement session when a golfer cannot control his hand release action through impact in a consistently reliable manner.

You wrote-: "Matt Kuchar made an informed choice based on his on-course golf performance and not on his SC data. He elected to ignore Scott Lynn's advice, and based on his PGA tournament record, he probably made the right choice. Not a hard decision when MK is informed and focusing on the right thing. Was Scott Lynn wrong in suggesting a possible correction? Of course not."

I disagree with your bold-highlighted statement! I think that it was stupid to attempt to make MK create a "Trifecta" pattern of SC measurements - considering the fact that he uses Hardy's one-plane golf swing action. In that type of golf swing action, one starts the downswing with a rotary pelvic/upper torso motion that should cause the rotary torque GRF to peak first, followed by a small amount of horizontal GRF happening later due to a secondary shift targetwards of the torso. There is also no need to increase the vertical GRF in that type of golf swing action.

The same applies to Boo Weekley.

 

Note that BW's rotary torque GRF starts first and well before he starts to use any horizontal GRF, which is probably a secondary phenomenon. That makes sense considering that he uses the same one-plane swing type of rotary motion as Matt Kuchar.

You also wrote-: "What about the player who has obvious swing errors yet has a normal GRF profile? Well, this is still probably better than having a poor GRF profile, and it shows the player is doing something correctly."

I totally disagree with your reasoning. What is a "normal GRF profile" and what is a" poor GRF profile"? Yann had a perfect "Trifecta" GRF profile despite having a very poor golf swing pivot motion. Why is that better than the "poor" GRF profile manifested by Matt Kuchar and Boo Weekley?

How can you assume that a golfer is "doing something correctly" just because the recorded GRF profile is regarded as being a "normal GRF profile" if the GRFs can be entirely "normal" in the presence of very poor pivot (body and leg) motions?

You also wrote-: "But, I assume most players can get a specific baseline GRF force-print when they are hitting the ball at their best and a slightly different one when they are hitting the ball poorly. To me, this is what makes SC a potentially good feedback tool. This way the player can work on swing mechanics that bring back the "good" hitting GRF profile as fast as possible and see if it solves the on-course swinging problem."

That would only make sense if there is direct/positive correlation between good ball striking and a good SC GRF profile. However, I know of no reason to believe that there is a strong positive correlation between good golf swing biomechanics involving the body/arms and the secondary GRF measurements recorded at the level of the ground.

You also wrote-: "But, most likely SC will provide enough players enough useful guidance to justify its use. If so, it will grow in popularity. If not, it will fade out of existence. Time will tell."

I agree that "time will tell", but it will take many, many years because too many golf instructors are foolish enough to strongly "believe" in the usefulness of their tech teaching aids, and not smart enough to know that they don't make sense (eg. HackMotion training device) from a golf swing biomechanical perspective.

Jeff.

[imperfectgolfer]

The more I think about SC measurements, the more I think that they have no useful value from a golf instructional perspective.

Let's consider two present-day PGA tour golfers who are superb ball strikers - Scottie Scheffler and Sam Burns.

I will analyse their pelvic motion during their downswing and theorise on their likely SC measurements.

Scottie Scheffler's driver swing.

Image 1 is at P4, image 2 is at P5, image 3 is at P6, and image 4 is at P7.

I have drawn vertical red lines starting at the outer border of his two feet. I have drawn a red circular marker over his upper swing center and a blue circular marker over his lower swing center at P4.

At P4, one can see that he has a vertical-centralised upper torso loading pattern and a centralised pelvic loading pattern.

Note how much his pelvis shifts between P4 => P5. It would be reasonable to suspect that he is generating a large horizontal GRF starting before, or at P4.

Note how his lead leg straightens at P6/P7 and I could imagine that he must be exerting a large vertical GRF and a large negative horizontal GRF to "brake" his pelvic shift motion to prevent himself from becoming unbalanced during his later downswing.

Sam Burns' driver swing.

Image 1 is at P4, image 2 is at P5, image 3 is at P6, and image 4 is at P7.

I have drawn vertical red lines starting at the outer border of his two feet. I have drawn a green circular marker over his upper swing center and a red circular marker over his lower swing center at P4.

At P4, one can see that he has a rightwards-centralised upper torso loading pattern and centralised pelvic loading pattern.

Note that there is very little targetwards shift of his pelvis happening during his hip-squaring phase between P4 => P5. I suspect that he has a small horizontal GRF and a large rotary torque GRF measurement. I also suspect that he does not need to generate a large vertical GRF and a large negative horizontal GRF ("braking force").

Is there any value in performing a SC-GRF measurement to verify or contradict my suspicions? Would those golfers be inclined to change their pivot motion as a result of knowing those SC-GRF measurements? Would it make sense to tell either of those golfers to increase any one of those horizontal, rotary torque or vertical GRFs if they did not reach the PGA tour average zone (black zone)?

I think that the answer is "No!" to all those questions.

I asked Milo Lines whether knowing the SC results of his driver golf swing action changed the way he performs his pivot motion. He stated that he had perfected his pivot motion years before his GRFs were measured by a SC device, and it did not change his "ideas" on how best to perform his driver golf swing action.

Scottie Scheffler and Sam Burns have a very different pattern of pelvic motion during their driver golf swing action, which works very well for them. I cannot envisage why they should even bother to be measured by a SC device. What information would it supply that could make them inclined to change the biomechanical  execution of their pivot motion during the downswing of their driver swings?

Jeff.

[imperfectgolfer]

I am progressively losing interest in the prospect of writing about golf swing biomechanics so I do not post much in the absence of specific questions from forum members, but I just saw this Jamie Sadlowski video where he drives the ball 330 yards off-his-knees.





Do you really believe that one can gain insights into his golf swing biomechanics by placing him on a Swing Catalyst device and measuring the horizontal GRF, rotary torque GRF and vertical GRF being generated under each knee?

Jeff.

[imperfectgolfer]

Here is another swing video featuring Scott Lynn (SL), and this video again shows that SL uses unscientific reasoning.





This is a BBG video where SL is trying to get Brendon Devore to increase his vertical GRF with the purpose of generating a larger maximum clubhead speed at impact.

SL argues that if a golfer maximises his vertical GRF to reach into the tour average range at ~P5.2 that it will have two advantages - i) it will cause improved lead shoulder elevation between P5.5 => P7, which can increase the centripetal component of the lead hand's MoF between P5.5 => P7 and thereby increase the efficiency of the release of PA#2 and that should obviously increase clubhead speed and ii) that it will flatten the clubhead path in the ~12-15" of clubhead travel distance between P6.7 => P7.

SL uses Collin Morikawa as an example of a golfer who generates a large vertical GRF - even when hitting short irons. Watch the BBG video between the 2:50 - 5:40 minutes time points. SL claims with respect to CM that by increasing his vertical GRF, which reaches its maximum value at P5.2, that it allows CM to then cause his hand arc path to become more elevated between P5.5 => P7 and that should produce those two previously mentioned benefits.

Let's consider CM's hand arc path.

The red splined path is CM's hand arc path.

Image 1 is at P4, image 2 is at P5, Image 3 is at P5.5, image 4 is at P6.7 and image 5 is at impact.

Note that CM is squatting to a small degree during his hip-squaring phase that happens between P4 => P5, but the amount of head-dropping is small.

Note that CM's lead shoulder is only slightly higher than his trail shoulder at P5.5 and his maximum vertical GRF value is reached sometime between P5 => P5.5.

Note that CM's lead shoulder elevates significantly between P5.5 => P7 and that will cause his hand arc path to become relatively horizontal between P6 => P7 with a slight uplift happening between P6.5 => P7.

SL believes that CM's desirable pattern of lead shoulder elevation that is happening between P5.5 => P7, and his desirable hand arc path pattern between P6 => P7, is caused by his efficient generation of a very large vertical GRF, which is maximised at ~P5.2. 

However, SL's conclusion  is totally unscientific and meritless. CM is not a "jumper" who uses Mike Adam's "launcher" pattern of pelvic motion (as seen in Justin James driver golf swing action) and the biomechanics underlying his pelvic/torso motional pattern between P5.5 => P7 can be performed without generating a large vertical GRF at ~P5.2.

Consider Gary Woodland's Swing Catalyst measurements.

Note that GW produces a very small vertical GRF (cyan graph) that is well below the tour average.

However, he can generate the same biomechanical lead shoulder elevation pattern as CM, and also the same hand arc pattern.

Here is Gary Woodland's hand arc path.

The red splined path is GW's hand arc path, which has the same overall shape as CM's hand arc path.

Image 1 is at P4, image 2 is at P5, image 3 is at P5.5 and image 4 is at impact.

Note GW has minimal squatting motion during his hip-squaring phase between P4 => P5. Note that his shoulders are level at P5.

Note that GW starts elevating his lead shoulder at P5.5 to a greater degree than CM without needing to generate a large vertical GRF between P5 => P5.5.

Note that GW elevates his lead shoulder efficiently between P5.5 => P7 and it is not less efficient than CM's lead shoulder elevation pattern. Note the GW has the same horizontal hand arc path between P6 => P6.5 with a slight uplift between P6.5 => P7 as seen in CM's driver swing - without needing to generate a large vertical GRF at ~ P5.2.

Here are capture images showing his clubhead motion in his later downswing.

Image 1 is at P6.5, image 2 is at P6.7 and image 3 is at P7.

Note that his clubhead is level with the ball at P6.7 and that he has a "flat spot" in his clubhead arc in the 12 - 15" of clubhead travel between P6.7 => P7. In fact, his clubhead is traveling more level to the ground between P6.7 => P7 than CM's clubhead because CM has far more forward shaft lean due to his exaggerated bowed lead wrist technique.

This comparison shows that one can generate i) an optimum lead shoulder elevation pattern and an optimum hand arc path between P5.5 => P7 without ii) generating a large vertical GRF at ~P5.2. There is no direct causal relationship between i) and ii).

Watch SL getting Brendon to use his rubber band drill between the 9:27 - 9:45 minute time point of BBG video. That drill can be performed with, or without, generating a large vertical GRF before the stretching-out of the rubber band phase that is due to lead shoulder elevation. The same phenomenon applies to Brendon's "real life" golf swing in the later part of that BBG video where he carries the ball >24 yards further due to a better biomechanical pattern of i) lead leg straightening and ii) lead shoulder elevation - it is possible to perform those  two biomechanical actions with, or without, generating a very large vertical GRF at P5.2.

Jeff.