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Post by imperfectgolfer on Apr 5, 2020 9:36:10 GMT -5
Hi UG looking at the left leg extended for KB where he might be using GRF forces to increase clubhead speed (ie. parametric acceleration) but I don't think its very large (but obviously important for long drive competitions). Strangely enough , I was looking at JS's swing here on 3D Gears and checked out his 'Grip Speed' on the video below . Some things I noticed were: 1. Around P5 his speed was approx. 25.91 mph 2. Around P6.5 his speed drops to 21.02 mph (as PA#2 releases - clubhead increases speed , while his grip speed drops) 3. At around P7 his speed increases to 24.51 mph In several other golfers on Gears, the grip speed keeps dropping after PA#2 release but in JS's case , he upped it by about 3.5 mph . So the 'jumping up' and snapping of left leg extension (that Tiger used to do) maybe to utilise 'Parametric Acceleration' effect doesn't seem to add much clubhead speed . DG With respect to the concept of parametric acceleration that is due to shortening of the hand arc path near impact, it works by increasing clubhead speed to a small degree without increasing hand speed. Jeff.
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Post by imperfectgolfer on Apr 5, 2020 9:50:40 GMT -5
UG stated-: "I played golf with Jeff today and he helped me to see the value of the right arm adduction maneuver. One example is to swing with the left arm only and to notice how fast the left arm moves from p4 to p5.5, and then to repeat this with both hands on the club with the addition of the right arm. Not only does the right hand provide stability and help guide the hand arc path, but the right arm adduction maneuver increases the hand speed from p4 to p5.5. Another important insight is that the right arm adduction maneuver shouldn't be applied beyond p5.5, since this can over-accelerate the left arm into impact and not provide sufficient time to release PA#2.
Of course, we all agree that the pivot is what drives the master power accumulator #4, but the right arm adduction maneuver is important when applied correctly and is an integral part of the swing."
It is important to understand that to apply the right arm adduction maneuver correctly between P4 and P5.5, in order to help increase the speed of release of PA#4, that the right shoulder must move downplane secondary to the counterclockwise upper torso rotation so that the golfer can maintain an unchanged degree of right elbow bend between P4 and P5.5. If a golfer cannot get the right shoulder moving fast enough downplane (which requires a certain degree of right lateral bend) then the right elbow will straighten between P4 and P5.5 and the right arm adduction maneuver will contribute far less to increasing the speed of release of PA#4.
Jeff.
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Post by dubiousgolfer on Apr 5, 2020 10:03:04 GMT -5
Dr Mann Apologies , yes you are correct . It seems that its the sudden change in direction of the hand path , not its hand speed that invokes PA. people.stfx.ca/smackenz/Courses/DirectedStudy/Articles/Miura%202001%20Parametric%20acceleration%20effect%20of%20inward%20pull.pdfSo how can we explain JS's increased hand speed after release of PA#2? First his hand speed was increasing up to release, then it decreased as expected during PA#2 release , then it increased into impact. DG PS. Could his left arm bending action have some influence on the increased hand speed from say P6.5-P7? Addendum: On reflection , although PA can happen by an acute change of direction while not increasing speed as per Miura's article above, the physics is the same as PA#2 release (which also depends on hand speed/path). So if a golfer was able to increase his hand speed while also acutely changing direction from P6.5/P7 , then PA effect would still occur (and clubhead speed would be greater). Actually , I do not recognise PA as being some unique phenomenon but just another way to use 'eccentric forces' to create a little extra clubhead speed closer to impact. But there is still the puzzle about how JS increases his hand speed from P6.5 (could he be actively pushing on PP#1 with his right hand?).
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Post by dubiousgolfer on Apr 5, 2020 10:38:13 GMT -5
UG stated-: " I played golf with Jeff today and he helped me to see the value of the right arm adduction maneuver. One example is to swing with the left arm only and to notice how fast the left arm moves from p4 to p5.5, and then to repeat this with both hands on the club with the addition of the right arm. Not only does the right hand provide stability and help guide the hand arc path, but the right arm adduction maneuver increases the hand speed from p4 to p5.5. Another important insight is that the right arm adduction maneuver shouldn't be applied beyond p5.5, since this can over-accelerate the left arm into impact and not provide sufficient time to release PA#2.
Of course, we all agree that the pivot is what drives the master power accumulator #4, but the right arm adduction maneuver is important when applied correctly and is an integral part of the swing." It is important to understand that to apply the right arm adduction maneuver correctly between P4 and P5.5, in order to help increase the speed of release of PA#4, that the right shoulder must move downplane secondary to the counterclockwise upper torso rotation so that the golfer can maintain an unchanged degree of right elbow bend between P4 and P5.5. If a golfer cannot get the right shoulder moving fast enough downplane (which requires a certain degree of right lateral bend) then the right elbow will straighten between P4 and P5.5 and the right arm adduction maneuver will contribute far less to increasing the speed of release of PA#4. Jeff. Dr Mann - when you say "If a golfer cannot get the right shoulder moving fast enough downplane (which requires a certain degree of right lateral bend) then the right elbow will straighten between P4 and P5.5 " , does that mean the golfer will have no choice but to straighten the elbow so they don't "run out of right arm" by P7? DG
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Post by utahgolfer on Apr 5, 2020 16:13:53 GMT -5
I'm confused on how the right shoulder needs to move down plane fast enough to support right arm adduction, but at the same time left shoulder rotation needs to move horizontal for long enough to optimize the acceleration of PA#4 while right shoulder rotation must not prematurely cause the hand path to swing over the top.
Can we sort this out?
There are also three short Milo Lines videos I would like to discuss in a new thread, that hits on this topic.
UG
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Post by dubiousgolfer on Apr 5, 2020 17:36:58 GMT -5
Hi UG
This is my interpretation from Dr Manns posts (hope I've got this correct).
I thought the left shoulder 'socket/protracted scapular' and ribcage is being rotated by the active pivot CCW from P4 . The rotating ribcage slides under the 'originally' retracted right scapula (created in the backswing at P4). As the ribcage slides under the right scapula (essentially becoming passively less retracted), we then have the independent movement of the right shoulder socket being moved downplane with lateral flexion and right arm adduction.
DG
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Post by imperfectgolfer on Apr 5, 2020 17:54:12 GMT -5
I'm confused on how the right shoulder needs to move down plane fast enough to support right arm adduction, but at the same time left shoulder rotation needs to move horizontal for long enough to optimize the acceleration of PA#4 while right shoulder rotation must not prematurely cause the hand path to swing over the top. Can we sort this out? There are also three short Milo Lines videos I would like to discuss in a new thread, that hits on this topic. UG UG - Simply look at the back view capture images of the pro golfers that I have already posted in this thread at newtongolfinstitute.proboards.com/thread/763/narrowing-clubhead-path-early-downswing?page=2 - note that their right scapula is becoming less retracted as the upper torso rotates counterclockwise and that the right shoulder socket moves more downwards (rather than outwards) due to some degree of right lateral bend, which lowers the peripheral end of the right clavicle, and due to increased secondary axis tilt. DG - you asked-: "Dr Mann - when you say "If a golfer cannot get the right shoulder moving fast enough downplane (which requires a certain degree of right lateral bend) then the right elbow will straighten between P4 and P5.5 " , does that mean the golfer will have no choice but to straighten the elbow so they don't "run out of right arm" by P7?" If the golfer straightens the right arm prematurely between P4 and P5.5 due to a "high" right shoulder (as seen in Phil Mickelson's driver swing action) then he will likely "run-out-of-right arm" in the later downswing and the right palm may lose contact with PP#1 before-or-through impact. Jeff.
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