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Post by dubiousgolfer on Jul 18, 2020 19:36:24 GMT -5
So does this mean for long clubs , 'Flexion to Extension Model B' has less dispersion than a DHer ? DG Why do you make this assumption? Scott's model B shows continued lead wrist flexion => extension happening continuously through impact, which is theoretically incompatible with a DH-hand release action? Jeff. Dr Mann Look at the bullet point 5 in the below video screen image for model B . He says 'possible more consistency in start line over other methods'. So I'm assuming clubface vector moves more vertically but less horizontally through impact . Not sure what he means by 'start line ' but I think its the ball target line. Therefore isn't he implying that the Model B will have less consistent launch angle but not veering as much with reference to the ball-target line through impact?  DG PS. He says 'possibly ' so its just his own opinion which might be incorrect. |
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Post by imperfectgolfer on Jul 18, 2020 19:50:37 GMT -5
Major find! Scott Cowx sent me a HackMotion 3D graph of Henrik Stenson's golf swing. I have always wanted to see HS's wrist angles in 3D format. I cannot post HS's 3D graph here because Scott asked me to keep it confidential, but it is very similar to the following graph. Henrik Stenson's graph shows the same blip-plateau in the lead wrist flexion graph between P7 => P7.2+ showing that his lead wrist does not rapidly extend through impact and it shows the same blip-plateau in his ulnar deviation graph. His lead wrist is flexed ~2 - 5 degrees between P7 and P7.2+ and there is no rapid/massive extension happening between P7 => P7.2.
The major difference is that HS has a lot more lead wrist extension at P4 and his lead wrist flexion-extension graph moves slowly/progressively/steadily in the direction of flexion between P4 => P7 and an absolute degree of lead wrist flexion only happens just before impact and it measures ~ 2 degrees at impact. In other words, it shows exactly the same phenomenon seen in these capture images of HS's downswing.  Note that HS's lead wrist is slightly extended at P5 and at P5.5. It is less extended at P6 and P6.5 and it is slightly flexed (~ 2 degrees) at P7 and P7.2 with no significant change in lead wrist flexion happening between P7 and P7.2 (because HS is a DHer). That slowly progressive/steady change in lead wrist extension => flexion between P4 => P7 is exactly what one would expect in a DHer who uses a neutral left hand grip and who also uses an intact LFFW/GFLW swing technique throughout the entire downswing and where the lead wrist automatically/naturally becomes less extended as it moves from being radially deviated at P5 to being ulnar-deviated at impact while the lead wrist remains geometrically flat.
In conclusion, there is 100% concordance between HS's 2D capture images and his HackMotion's 3D data and they are both 100% concordant with an an intact LFFW/GFLW golf swing action throughout the entire downswing and early followthrough if the golfer uses a neutral left hand grip.
Jeff.
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Post by dubiousgolfer on Jul 18, 2020 20:08:49 GMT -5
Yes that is a good find and very nice of Scott to send you those HS graphs.
DG
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Post by dubiousgolfer on Jul 18, 2020 21:25:13 GMT -5
With regards to Scotts Model B Flexion-Extension release , where in his opinion , the clubface will not veer as much with reference to the 'start line' (which I've assumed is the ball target line) through impact . Wouldn't that imply that the 'release action model B' is changing the incline plane of the swing through impact? SMK mentions the following as one of several ways to change the ROC : golf.com/instruction/what-is-rate-of-closure-golf-swing-sasho-mackenzie/----------------------------------------------------------------------------- How to change your Rate of Closure, #2: Change the “incline plane” of your swing The club is swung down and around the body on the forward swing, which presents the Inclined Plane knob. Turning this knob to zero would result in moving the clubhead in a vertical plane like a Ferris wheel (0° from vertical). At a driver speed of 90 mph, an Incline Plane knob turned up to 30° from vertical (a steep move through impact) contributes about 800 °/s to RoC. Cranking the knob up to a relatively flat 45° from vertical, increases the contribution to 1200 °/s. There may be reasons to change the pitch of your swing, but reducing RoC shouldn’t be one of them. Tour players tend to have relatively similar vertical swing planes with driver (40° to 45° from vertical) and most amateurs are too vertical already. -------------------------------------------------- The above suggests that a more vertical swing plane 'through impact period' caused by Flexion-Extension might decrease the ROC, so theoretically Scott might have a case for saying this is a possibility but imho difficult to prove. DG PS. On reflection , I cannot see how lead wrist flexion-extension alone can change the inclined angle of the swing plane - it could change the angle of attack . One would need to have increased ulnar deviation of the lead wrist while flexion-extension was happening through impact. But extension is normally coupled with radial deviation , not ulnar deviation. |
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Post by syllogist on Jul 18, 2020 23:17:34 GMT -5
Dr. Mann,
I believe that rapid left hand extension at impact and slightly beyond does not happen to all golfers because of the collision.
The clubhead decelerates 20% upon collision and the hands do not. Consider the extreme - what would happen to the hands if the the ball were immovable and the clubhead collided with the ball? - the hand would continue to travel a short distance after the collision and would not seek extension.
Also, doesn't ulnar deviation of the left hand tend to inhibit extension?
S
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Post by dubiousgolfer on Jul 19, 2020 12:04:31 GMT -5
Dr Mann
You mentioned in a previous post the following:
"Jon stated that any blip-plateau phenomenon seen immediately post-impact in his lead wrist flexion-extension graphs is due to ball collision and he states that it is seen in all his pro golfers (DHers and non-DHers). He also stated that it disappears if a ball is absent."
So is JS inferring that the HackMotion graphs showing those blips are due to club/ball impact?
DG
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Post by imperfectgolfer on Jul 19, 2020 20:08:29 GMT -5
Dr Mann You mentioned in a previous post the following: "Jon stated that any blip-plateau phenomenon seen immediately post-impact in his lead wrist flexion-extension graphs is due to ball collision and he states that it is seen in all his pro golfers (DHers and non-DHers). He also stated that it disappears if a ball is absent." So is JS inferring that the HackMotion graphs showing those blips are due to club/ball impact? DG I can imagine JS adopting that position, but the problem is that the HackMotion blip-plateau phenomenon is only seen in a subset of pro golfers, who use the option A swing pattern, and it does not happen in golfers who use the option B swing pattern, which does not make sense if it is secondary to ball contact. Jeff. |
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Post by imperfectgolfer on Jul 19, 2020 20:12:07 GMT -5
Dr. Mann, I believe that rapid left hand extension at impact and slightly beyond does not happen to all golfers because of the collision. The clubhead decelerates 20% upon collision and the hands do not. Consider the extreme - what would happen to the hands if the the ball were immovable and the clubhead collided with the ball? - the hand would continue to travel a short distance after the collision and would not seek extension. Also, doesn't ulnar deviation of the left hand tend to inhibit extension? S Why does that phenomenon not happen to all pro golfers - specifically the HackMotion option B pro golfers? Jeff. |
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Post by imperfectgolfer on Jul 20, 2020 13:20:42 GMT -5
I asked Scott Cowx to send me a HackMotion graph of a golfer who does not have any temporary blip-plateau in "lead wrist extending" phenomenon happening immediately post-impact. Here is the graph that he sent me.
Note that the lead wrist flexion-extension graph (green graph) shows lead wrist flexion happening in the mid downswing that peaks in the late downswing before impact, and that then moves towards "lead wrist extending" before impact, and also through impact, with no temporary blip-plateau "lead wrist extending" phenomenon happening immediately post-impact between P7 and P7.2. That suggests that ball collision cannot be causally responsible for any temporary blip-plateau "lead wrist extending" phenomenon seen immediately post-impact - because it should also be seen in this golfer's graph. He also sent me a HackMotion graph of Dustin Johnson's swing which shows a very dramatic temporary plateau-phenomenon in "lead wrist extending" happening post-impact between ~P7 => P7.4, which is even more dramatic than the one seen in Henrik Stenson's swing and the following graph of an option A golfer.
These facts are very interesting!!!
Jeff.
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Post by dubiousgolfer on Jul 20, 2020 18:53:05 GMT -5
I think I now understand Scott Cowx opinion regarding the use of Model B Flexion-Extension for long clubs. hackmotion.com/push-draw-vs-pull-fade-swing-pattern/Here are images of how the 'clubface vector' (ie. an arrow pointing normal to clubface) of a golfer trying to 'PULL FADE' with a Model A (stable wrist) and Model B (Flexion-Extension) Model A Yellow arrow is showing how the clubface vector is moving from being pointed high right before impact to low left after impact. Green lines are showing where the clubface vector is pointed at each frame.  Model B Yellow arrow is showing how the clubface vector (direction) is moving from being pointed low right before impact to high left after impact. Green lines are showing where the clubface vector is pointed at each frame.  The yellow arrow depicts how the clubface vector arrow direction shifts 'approaching/through' impact but Model B 'clubface vector' change is more aligned with the start line than Model A. DG |
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Post by dubiousgolfer on Jul 20, 2020 20:30:31 GMT -5
Dr Mann
Do you happen to know what HackMotion's sampling rate is?
DG
ps. No need to answer my question as I've found out it's 100 Hz
"Captures 100 frames per second (100Hz)"
Doesn't this mean that it must be using 'smoothing' algorithms for the very fast wrist rotation purple graphs? Why isn't 3D AMM not showing such distinct 'plateau' areas on their 'Flex-Extn' graphs from P7-P7.2 if it works at a much higher sampling rate (240 Hz)?
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Post by imperfectgolfer on Jul 20, 2020 22:29:33 GMT -5
Dr Mann Do you happen to know what HackMotion's sampling rate is? DG ps. No need to answer my question as I've found out it's 100 Hz "Captures 100 frames per second (100Hz)" Doesn't this mean that it must be using 'smoothing' algorithms for the very fast wrist rotation purple graphs? Why isn't 3D AMM not showing such distinct 'plateau' areas on their 'Flex-Extn' graphs from P7-P7.2 if it works at a much higher sampling rate (240 Hz)? It is interesting that AMM is not showing these plateau areas between P7 and P7.2 despite a higher sampling rate. I wonder why it is not happening. Jeff. |
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Post by dubiousgolfer on Jul 21, 2020 6:30:05 GMT -5
Dr Mann
HackMotion's sampling rate seems very small at 100 Hz.
The average tour pro swings the driver at 113 mph and lets say clubhead speed is reduced by 20% at impact , that would mean a speed of about 90 mph = 132 ft per second post impact.
132ft is equivalent to 1 second
If the club travels approx 2 ft post impact, the time taken would be approx (1/132) x 2 = 0.0152 secs (I'm assuming a straight path post impact as an approximation)
HackMotion has a sampling rate of 100 Hz per second
1 sec is equivalent to 100 samples
0.0152 secs is equivalent to 100 x 0.0152 = 1.5 samples
So I don't understand how HackMotion could show such detail on the graph post impact using approx 1.5 data samples.
DG
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Post by imperfectgolfer on Jul 21, 2020 7:06:06 GMT -5
Dr Mann HackMotion's sampling rate seems very small at 100 Hz. The average tour pro swings the driver at 113 mph and lets say clubhead speed is reduced by 20% at impact , that would mean a speed of about 90 mph = 132 ft per second post impact. 132ft is equivalent to 1 second If the club travels approx 2 ft post impact, the time taken would be approx (1/132) x 2 = 0.0152 secs (I'm assuming a straight path post impact as an approximation) HackMotion has a sampling rate of 100 Hz per second 1 sec is equivalent to 100 samples 0.0152 secs is equivalent to 100 x 0.0152 = 1.5 samples So I don't understand how HackMotion could show such detail on the graph post impact using approx 1.5 data samples. DG I agree! I am in contact with HackMotion and I have posed that question to them. Jeff. |
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Post by dubiousgolfer on Jul 21, 2020 10:53:15 GMT -5
I posed the question 2 days ago on one of their You-Tube videos (no reply yet).
DG
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