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Post by imperfectgolfer on Feb 22, 2020 10:04:06 GMT -5
Many thanks Dr Mann - I'm wondering whether Shaun/Mike are aware that they are suggesting golf instruction based on questionable 3D Gear data? Yet they continue to delete You-Tube comments that might question their reasoning. Just doesn't seem right to me. DG I have no reason to believe that the AMG instructors think that the GEARS avatars are questionably accurate. I am also not surprised that they delete you-tube comments that question their reasoning. I have never discovered an online golf instructor who can handle negative comments in their you-tube comment section without deleting them. Jeff.
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Post by utahgolfer on Mar 25, 2020 19:38:12 GMT -5
Here is Kiradech Aphibarnrat's golf swing to add to this thread showing a possible increase in the bend of his right elbow to narrow the width of his downswing arc. Also, based on the speed of this swing, he might automatically bend his left elbow as this occurs due to right arm impedance, as discussed in another topic thread.
UG
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Post by imperfectgolfer on Apr 2, 2020 17:01:14 GMT -5
Here again is this AMG video. Here are a series of capture images of the 3 pro golfers at P4, P5 and P5.5. P4 Note that their right arm is abducted away from the right side of their torso at P4. P5
Note that they are not adducting their right arm closer to the right side of their torso, and note the widening right elbow bend angle. P5.5 Note that they are not adducting their right arm closer to the right side of their torso, and note the widening right elbow bend angle. Now, look at Rory McIlroy (who they mention in their video). Image 1 is at P4, image 2 is at P5 and image 3 is at P5.5. Note how he is adducting his right arm progressively closer to the right side of his torso without widening his right elbow bend angle between P4 => P5.5. Phew!!! What a difference!!! Jeff.
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Post by dubiousgolfer on Apr 2, 2020 19:18:52 GMT -5
Dr Mann
So is Gears measuring elbow bend incorrectly and also not measuring right arm adduction? Just wondering whether the other 3D systems like AMM have different findings?
DG
PS. Apologies , we discussed this in a previous post.
"DG,
At the 0:49 minute time point of the video, Michael Neff shows how to place the elbow marker in position. Therefore, 3 markers (wrist, elbow and AC markers) can be used to assess the degree of right elbow bend with reasonable accuracy. I use the word "reasonable" because it would be better to have a marker placed at the level of the humeral head, and not at the AC joint. However, I wonder whether the GEARS system can really differentiate between a pitch and a punch elbow motion with reasonable accuracy - especially considering the fact that the wrist marker will be rotating a lot as the right forearm pronates/supinates while the humeral head will be sliding sideways under the acromium process at the AC joint as the humerus moves from abduction => adduction. It is also possible that scapula retraction => protraction actions can cause variable degrees of AC joint separation that will also affect the position of the humeral head relative to the AC marker placed on top of the shoulder.
Jeff."
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Post by imperfectgolfer on Apr 2, 2020 22:50:51 GMT -5
DG, I do not really know whether GEARS is measuring the right elbow bend angle and the degree of right arm adduction correctly - but it should be capable of accurate measurements. Another interesting point - look at the position of those 3 pro golfers' hands at P5.5 and note that they are vertically above a point that is well outside the right foot in the 1st and 3rd golfer. Now, look at these pro golfers. Dustin Johnson Note his fully adducted right arm and note that his hands at P5.5 is vertically above his right foot. Jamie Sadlowski Note his fully adducted right arm and note that his hands are vertically above a point that is slightly inside his right foot at P5.5 (image 2). Henrik Stenson Note his fully adducted right arm and note that his hands at P5.5 (image 2) is vertically above his right foot. Sergio Garcia Note his fully adducted right arm and note that his hands at P5.5 (image 3) is vertically above the outer border of his right foot
Rory McIlroy Note his fully adducted right arm and note that his hands at P5.5 (image 3) is vertically above the outer border of his right foot. Jeff.
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Post by dubiousgolfer on Apr 3, 2020 10:46:32 GMT -5
Dr Mann - Yes, it looks like your observations create more questions regarding the integrity of the Gears 'Kinematic' displays.
DG
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Post by syllogist on Apr 4, 2020 6:19:53 GMT -5
Dr. Mann,
If the angle of view of the avatar were directly above the avatar rather than above and in back of the avatar, the hands might not appear to be "well outside" the right foot (toward the target line).
S
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Post by dubiousgolfer on Apr 4, 2020 9:37:53 GMT -5
Dr. Mann, If the angle of view of the avatar were directly above the avatar rather than above and in back of the avatar, the hands might not appear to be "well outside" the right foot (toward the target line). S Hi S There does seem something wrong in Gears as we've seen discrepancies between their kinematic displays and real video frames before . Check this out for JS's P6 position Image 1 of the below Then look at frames 3:00 - 3:27 in the below video and you will note the difference in the elbow position . Also look at the orientation of the left wrist images 3 and 4 above near impact P7 compared to Gears similar images for that phase from 4:00 onwards. The Gears images show the back of the left wrist facing the target whereas above they are facing more towards the target line. DG
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Post by dubiousgolfer on Apr 4, 2020 9:54:17 GMT -5
Gears has the same issue with Jonas Blixt in this you tube video below at P7 ( frame 3:22 approx ) and 4:44 on the Gears video.
Also look at frame 3:21-3:22 (P6 approx) on the you-tube video vs 2:12 on the Gears video. The elbow positions look different too !
There does seem to be something inherently wrong with their mapping of the kinematics of the arms/elbows/forearms/wrists .
DG
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Post by dubiousgolfer on Apr 5, 2020 6:54:17 GMT -5
Here's another video which clearly shows how the humerus slides under the AC joint.
Maybe this Gears marker on AC joint (and possible Kinematic inaccuracy in their data) also explains Sean Webbs suggestion for a 'flat spot' move at the start of the downswing (at 4:08).
DG
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