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Post by dubiousgolfer on Aug 4, 2019 17:43:39 GMT -5
Dr Mann What I don't understand are these photo clips which seem to suggest (from a DTL view) that there is no rotation of the shoulder joints around a vertical axis. Is it because the actual movement of the shoulder sockets from P4-P5 is too small to visualise on these photo images? Or is it because these golfers are not using a pivot induced release of PA#4? PS. Actually ,has PA#4 even started releasing in any of these golfers by P5? Also , this top view shows a golfer whose left shoulder that doesn't seem to move in a curved rotational path from P4-P5 Here are some more DTL images DG
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Post by dubiousgolfer on Aug 7, 2019 7:32:08 GMT -5
Just found a few more videos from AMG that touches on this subject. Not sure about Mike Granato's explanation as to why the Pro left shoulder movement is superior to the AM (doesn't make any sense to me). I can only imagine that the Pro is using a swinging technique that promotes a more optimal hand speed and path (seems that the AM is using a punch elbow action - swing hitting?). DG
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Post by dubiousgolfer on Aug 11, 2019 6:32:35 GMT -5
Looking at all the golfer images above, most of them show that the left shoulder is almost stationary from a DTL 2D view (there could however be forward lateral motion towards target). The right shoulders seem to protract/depress from P4-P5 and wondering whether this movement is an actual 'extra loading' of PA#4 where the angle between the chest and left upper arm is made smaller. Could this be a stretch-shorten cycle phenomenon to assist the effectiveness of the pulling down component of PA#4 release and the independent 'outward' component of PA#4 caused by active upper body pivot?
On reflection is this just PA#5 happening initially to create hand speed but also help to load PA#4 ?
DG
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Post by imperfectgolfer on Aug 11, 2019 21:03:03 GMT -5
DG,
You wrote-: "What I don't understand are these photo clips which seem to suggest (from a DTL view) that there is no rotation of the shoulder joints around a vertical axis.
Is it because the actual movement of the shoulder sockets from P4-P5 is too small to visualise on these photo images? Or is it because these golfers are not using a pivot induced release of PA#4?
PS. Actually ,has PA#4 even started releasing in any of these golfers by P5?"
I think that it is difficult to assess the amount of left shoulder socket motion happening between P4 and P5 from a DTL viewing perspective. From a face-on viewing perspective, it is obvious that there is a lot of targetwards motion of the left shoulder socket happening between P4 and P5. The release of PA#4 (in the plane of left arm abduction) only happens after P5 and most of it happens between P5 and P6. However, PA#4 is releasing in the plane of left arm depression between P4 and P5 if the golfer has a very active right arm adduction maneuver that causes the hands to drop significantly between P4 and P5 (eg. as seen in Jamie Sadlowski's swing).
I am not impressed with Mike Granato's video on left socket motion during the early downswing. The main difference between the amateur and the pro is that the amateur has a poor right elbow pitch motion and he uses a suboptimal punch elbow motion.
I don't believe that right shoulder protraction between P4 and P5 produces a stretch-shorten cycle with respect to the degree of left arm adduction existing during that time period. I think that it makes it easier to perform the downward-component of the release of PA#4 due to an active right arm adduction maneuver.
Jeff.
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Post by dubiousgolfer on Aug 12, 2019 8:43:04 GMT -5
Many thanks Dr Mann
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Post by syllogist on Oct 2, 2019 10:37:44 GMT -5
To all,
I have read all of Dr. Allen's papers to date. Although I don't agree with a number of his suppositions and conclusions, I do commend him for much of the work he has done.
He has described release in terms of free roll (Vardon example), roll to (partial roll), and square to square (no roll). His conclusions concerning which of these release types used by each of the golfers he analyzed appears to be based on 1) photo-observed rotation of lack thereof of the lead hand and 2) how soon after impact the club passes the hands from a face-on view.
He has written that free roll requires a "pause" of the hands.
After I reread the Cameron Champ paper and looked at Vardon's release sequence, and then considered Dr. Allen's contention that free roll has the shortest radius over which the clubhead releases, it occurred to me what the free roll release actually is. I believe that the closer one comes to releasing the clubhead while the cap end of the grip remains stationary, the closer one comes to "free roll." I believe this would involve left hand extension through release as can be seen in Vardon's release.
Dr. Allen wrote that the radius of release with free roll is equal to the length of the club. I agree. Dr. Allen then concluded that since radius is a variable in the equation for centripetal acceleration, a release type other than that of free roll (whose radius is greater than the length of a club) does not take full advantage of centripetal acceleration and thus, the modern golf swing of the tour pro must rely on greater physical effort.
However, what I think that Dr. Allen did not consider regarding a "modern" release is that, since the hand path during release is curvilinear, (overhead perspective) the radius of curvature of the travel of the club is reduced during release. I'm not so sure that the modern swing is as inefficient as portrayed.
Thoughts?
S
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Post by dubiousgolfer on Oct 3, 2019 5:48:22 GMT -5
Hi S
I do not understand the physics of Dr Allen's opinion regarding 'taking full advantage of centripetal acceleration'. The centripetal force is acting towards the centre of a circle and does not influence the tangential speed of the clubhead (ie. along its club path).
DG
PS. Finding Ben Allen's terminology difficult to follow but I think he is advocating creating as much clubhead momentum up to the point of release and then redirecting the momentum of the club along a shorter radius. I think he is suggesting that by stalling the left arm and forcing the radius of the swing to be the clubshaft's length (around the wrists as a fulcrum point) will increase centripetal acceleration , which in turn (using the vector diagrams he's drawn) will increase clubhead speed.
He seems to be mixing up 'momentum' with force and adding a 'momentum' vector (which he calls 'momentum force') to the 'tension in the shaft' (ie. the centripetal force). You can't draw vector diagrams using different measurement units. Momentum in SI units is 'mass x velocity (kg*m/s)' , while Force is mass x acceleration (kg*m/s2
Or
Is he advocating active wrist torque around the lead wrist joint (as a fulcrum) to increase clubhead speed?
If the former , then he could be creating swing techniques based on flawed physics.
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Post by imperfectgolfer on Oct 3, 2019 9:36:42 GMT -5
S, You wrote-: " I believe that the closer one comes to releasing the clubhead while the cap end of the grip remains stationary, the closer one comes to "free roll." I believe this would involve left hand extension through release as can be seen in Vardon's release." I can certainly agree that a "free roll" release where the left hand slows down at impact and where the clubshaft whips passed the left arm thereby bending the left wrist could result in a small increase in clubhead speed - but at the great expense of a large amount of clubface roll through the immediate impact zone between P6.8 and P7.2. Mike Malaska teaches that type of release pattern - as seen in the following video.
However, I am not surprised that many modern-day pro golfers prefer to use a DH-hand release action through impact - as can be seen in the following capture images of Cameron Champ - where the clubface remains much more stable through impact. Jeff.
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Post by syllogist on Oct 3, 2019 9:37:48 GMT -5
Hi DG,
As I don't want to infringe and copy here Dr. Allen's work, first read "Functional Swing Deconstruction Nicklaus - Part 2, page 9, to understand his argument about "free roll" having a shorter circular radius than a swing something short of free roll.
The formula for centripetal force has radius as a variable and, given a certain velocity, the shorter the radius the greater the centripetal force.
Dr. Allen's definition of roll is (in the purest sense), during final release, the act of aligning the club from parallel to the target line to perpendicular to the target line. (Axial rotation of the shaft has nothing to do with how the club "rolls" and has nothing to do with centripetal acceleration even though there is axial rotation of the shaft during release.)
In a nutshell, Dr. Allen's argument is that anything less than free roll (completion of the release of the club when the butt of the grip is as stationary as possible) involves requiring 1) a stronger left hand grip and 2) greater body rotation by impact to accomplish that portion of free roll that is absent during roll of the club. He argues that the stronger left hand grip prevents the clubhead from prematurely "passing" the hands from a face-on view perspective. (Free roll encourages the clubhead to pass the hands.) He argues that the resultant more open body position by impact results in a greater radius over which the club can roll and thus centripetally accelerate, which reduces the potential centripetal acceleration. As a result, he argues that the resultant inefficiency requires greater and greater physical effort to achieve the clubhead speed absent such inefficiencies.
To put this all in perspective, Dr. Allen would believe that the modern tour pro builds the "centrifugal inefficiency" into his swing to avoid inconsistency in the timing of free roll.
I have no way of measuring the difference in radius of roll between Nicklaus and J.B. Holmes. However, I intuitively believe that if the modern swing does have a built in centrifugal inefficiency, it can't possibly result in any meaningful inefficiency during release.
S
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Post by dubiousgolfer on Oct 3, 2019 10:38:24 GMT -5
So lets look at an example of reduced radius (increased centripetal acceleration) of a rotating object, say the hands of a spinning ice-skater.
This is mentioned on Tutelmans website:
Ice skater analogy of the golf swing
The most important picture to keep in mind is the transfer of energy with unfolding.
Think of this as the reverse of the ice skater effect. The ice skater initially has the arms extended and works to move them as fast as possible. The skater then pulls the arms in close to the body. This causes the body speed up so that the skater spins fast. It is important to note that the hands actually slow down in this process, but we only watch the body. The body is spinning faster, true. But, because the hands' radius of rotation is shorter than before, the velocity of the hands is lower than before.
In the golf swing, the opposite occurs. The golfer initially holds the club close to the body using wrist cock, and works very hard to build up the kinetic energy in the body and arms. The golfer then allows the club to swing away from the body, so the body and arms slow down and the club speeds up. I emphasise the term “allows”, because it can be an entirely passive process; the golfer does not have to make the club swing out – it happens naturally.
In summary... The ice skater: First builds speed in arms, then folds the arms close to the body, to speed up the body The golfer: First builds speed in body, then unfolds the club from the body, to speed up the club.
However, if Ben Allen is really promoting a sudden change in hand path to increase clubhead speed , then that would make sense to me . When I look at Vardon's swing it looks like his hands 'turn the corner' and he releasing the club using the physics as explained by D'Alembert's principle . He looks like he is flipping through impact because he's stalled his pivot and left arm. I personally cannot see how purposely stalling the left arm will increase clubhead speed. But if those hickory shafts had lagging bend into impact , then I suppose Vardon could have used some active right wrist extension to flexion happening at or through impact to increase CHS.
DG
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Post by syllogist on Oct 4, 2019 7:46:31 GMT -5
Hi DG,
All good except that instead of "stall left arm and pivot," it's likely just the pivot that Vardon stalls. I think that continuing to pull to left arm is counterproductive in terms of wanting to allow the clubhead to "flee outward." The pivot is going to decelerate anyway; it's just a matter of when.
As a side note, Dr. Allen contends that intense arm speed during the acceleration phase is incompatible with a "hand pause" necessary for maximum centrifugal acceleration during final release. I don't think that this is even worth pondering when trying to build an efficient, elite swing.
S
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Post by dubiousgolfer on Dec 16, 2019 12:04:43 GMT -5
Just been looking at this video below and it contradicts Ben Allen's claim that the old hickory type shafts would break using modern day golf swings that power the golf swing earlier , especially from P4-P5. I might be wrong but I couldn't easily see much difference in the golf swings from hickory to steel but there were no shaft breakages. DG
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