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Post by utahgolfer on Apr 27, 2020 21:50:21 GMT -5
Here is a video by Chris Ryan discussing the importance of swinging the hands low enough by p6, by properly releasing PA#4 during the downswing. He states that keeping the left arm glued to the chest for too long will prevent the hands from attaining a low enough position, whereas releasing PA#4 starting at about p4.5 will allow the hands to swing lower, to about knee height at p6.
I assume this is another way to explain the "vertical drop", right arm adduction, and a proper hand arc path. Is this correct?
Chris Ryan also states that the right elbow straightens during the lowering of the hands, but doesn't a progressive right lateral bend lower the right shoulder enough so the right elbow does not need to straighten as he suggests?
Any input is appreciated.
UG
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Post by imperfectgolfer on Apr 28, 2020 9:35:51 GMT -5
UG, I think that it is a mistake to think that the lead arm is significantly more adducted at P4 than it was at P2. Most pro golfers (like CR), who use a one-piece takeaway, adduct their lead arm a lot between P1 and P2, and then there is very little further adduction happening between P2 and P4. The lead arm "feels" more pinned against the chest wall at P4 primarily due to greater lead arm elevation happening between P2 => P4, and not mainly due to a greater degree of lead arm adduction. The same principle applies to the early downswing between P4 and P5.5 where the lead arm does not change its degree of adduction very much, but it significantly changes its degree of elevation by lowering a lot between P4 and P5.5. Note that DJ's lead arm is adducted at P5.5 to roughly the same degree - compared to P4.
DJ can maintain a bent right arm between P5 and P5.5 because he has a lot of right lateral bend that lowers the right shoulder socket, but most pro golfers do not have enough right lateral bend and the right arm straightens to a small, and variable, degree between P5 and P5.5. Jeff.
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Post by utahgolfer on Apr 28, 2020 17:37:19 GMT -5
Jeff, wonderful explanation and clarity. I can now see how the left arm does not stay pinned to the chest during the backswing or downswing, and how it has its own important independent elevation and lowering phase. As you have taught, from p1 to p2, the left arm adducts across the chest with little independent left arm elevation, and from p2 to p4 there is mostly independent left arm elevation with little left arm adduction. Similarly, from p4 to p6 there is mostly independent left arm lowering and minimal left arm abduction, and from p6 to p7 there is mostly left arm abduction across the chest with minimal independent left arm lowering.
This means that the "vertical drop" involves independent left arm lowering (on the tilted plane), minimal left arm abduction, and occurs between p4 and p6. The horizontal tug, on the other hand, mostly involves left arm abduction across the chest, minimal left arm lowering, and occurs between p6 and p7.
So, I was completely mistaken that independent left arm motion mostly occurs after p5.5. Quite the opposite is true, as Jeff has illustrated.
Now, I wonder if the left arm is ever tied dependently to the shoulder/torso rotation during the backswing or downswing. From what I can see, the left arm always displays important independent motion via adduction, elevation, lowering, and abduction, from p1 to p7. Is this an accurate assessment?
UG
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Post by dubiousgolfer on Apr 28, 2020 18:18:00 GMT -5
Hi UG
So are you leaning towards an arm swinging release of PA#4 rather than a pivot release?
DG
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Post by utahgolfer on Apr 28, 2020 19:24:33 GMT -5
Hi DG,
No, that is the paradox. The left arm is still pivot driven but it has independent motion at the same time. Jeff can explain it better, but it is a mixture of both!
UG
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Post by imperfectgolfer on Apr 29, 2020 9:23:56 GMT -5
UG, You wrote-: "Now, I wonder if the left arm is ever tied dependently to the shoulder/torso rotation during the backswing or downswing. From what I can see, the left arm always displays important independent motion via adduction, elevation, lowering, and abduction, from p1 to p7. Is this an accurate assessment?"
There is definitely a finite degree of independence of left arm motion between P4 and P5.5 from the perspective of the downward phase of the release of PA#4, but the downward phase of the release of PA#4 must still be initiated by the pivot action that moves the left shoulder socket if one is going to use a pivot-driven TGM swinging action (and not the Leslie King "arm swinging" technique). The motion of the left shoulder socket between P4 and P5 should induce a marked downward (lowering) motion of the left arm, and the left shoulder girdle muscles and right arm adduction maneuver should only play a synergistically supportive role. Therefore, it would be incorrect to claim that the left arm motion between P4 and P5.5 is totally independent. I think that it is actually best to stop using the term "independent" and "dependent" when it comes to the release of PA#4 and one should simply think of the complex biomechanical interactions that are potentially in play to variable degrees.
Jeff.
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Post by dubiousgolfer on Apr 29, 2020 10:00:41 GMT -5
Dr Mann
So your definition of a pivot release of PA#4 includes both rotation of the upper torso and shoulder girdle contractions (but the former being dominant)?
But then how would one quantitatively confirm this was happening in a TGM pivot-driven swinging action?
DG
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Post by imperfectgolfer on Apr 29, 2020 10:55:12 GMT -5
Dr Mann So your definition of a pivot release of PA#4 includes both rotation of the upper torso and shoulder girdle contractions (but the former being dominant)? But then how would one quantitatively confirm this was happening in a TGM pivot-driven swinging action? DG I don't know how to quantify the amount of swing power the left shoulder girdles muscles contribute to a pivot-induced TGM swinging action's release of PA#4. I can only guess that it may potentially be in play - especially when you note that the left arm's angular velocity is faster than the upper torso's angular velocity between P4 and P5.5 (as seen in Jon Rahm's early downswing).
Jeff.
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Post by dubiousgolfer on Apr 29, 2020 18:31:16 GMT -5
Many thanks Dr Mann - I was actually wondering about quantifying the movement of the left arm from P4-P5 by the pivot action.
So for the latter to happen must there also be some connection between the left arm and upper torso to facilitate a pivot driven 'down and out' of the left arm from P4-P5?
DG
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Post by utahgolfer on Apr 29, 2020 19:42:26 GMT -5
Jeff, thanks for your input. I'm not sure of a better word to use. Of course, when I speak of independent or dependent motion of the left arm, it is never all or nothing. It is always a mixture of both.
The motion between the left arm and left shoulder torso is definitely a complex biomechanical interaction. And, there is a continuum from a golfer who embraces body rotation and pins the left arm to the chest during the swing with very little independent left arm motion, to the golfer who hardly rotates the body and swings with mostly independent left arm motion.
What a golf student needs to know is that the left arm both follows the lead of the pivot and also displays specific independent motions at specific times from p1 to p7.
To me, the left arm only drill helps a golfer focus more on a pivot driven left arm motion, while a two-handed practice swing drill could be used to focus on right arm adduction, right lateral bend, a pitched right elbow, keeping the right shoulder from moving toward the ball-target line too early in the downswing, and swinging the hands low enough during the downswing.
I look forward to your future writings on this topic and am elated that I finally understand this essential topic much more clearly.
UG
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Post by dubiousgolfer on Apr 29, 2020 21:35:50 GMT -5
So if I tried to summarise below:
1. No pinning of left arm to upper torso - PA#4 release by shoulder girdle contractions. 2. Some pinning of left arm to upper torso - PA#4 release could theoretically be a mix of 'pivot driven' and shoulder girdle actions. 3. If we were able to quantitatively assess the ratios of their PA#4 involvement we could then properly define the action as 'pure' , 50/50 mix, or non 50/50 mix with one dominant over the other.
So is there a necessity of having 'some' pinning of the left arm to upper torso (with PA#4 released solely by the pivot action) a better definition of a pure TGM swinging action?
DG
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Post by dubiousgolfer on Apr 30, 2020 8:20:45 GMT -5
Am I correct that a pure TGM swinging action can be represented by the action of the Iron Byron machine in the video below (where PA#4 is released by the pivot)?
I don't think there is an 'pinning' of the arm to its 'torso' and am assuming that the 'arm' angular acceleration is only influenced by the speed and circular path of the offset 'shoulder' joint (powered by the central pivot).
Therefore the release of the 'arm' (PA#4 in TGM terms) is the same physics that is being used to release PA#2 (ie. D'Alemberts principle).
So there is no need for any pinning of the left arm to the torso , so my previous post is incorrect.
PS.
I'm struggling to make sense of the Iron Byron machine because its equivalent 'left arm /shoulder and pivot centre' are always in a straight line . I need to think a bit more deeply about this :-)
It's basically a double-pendulum isn't it?
I think a triple pendulum is a more realistic representation of the golf swing and therefore the PA#4 release of the left arm does follow the same principle as PA#2 release for a purely pivot driven swing . Therefore there is no need for any pinning of the left arm to produce a pure TGM swinging action.
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Post by syllogist on Apr 30, 2020 16:10:41 GMT -5
Hi DG,
Left arm "pinning" to the torso in the backswing, or adduction, is equivalent to making the maximum backswing of the left arm in that the greater the adduction, the longer the backswing. "Pinning" during the downswing allows sequential rotation of the torso then arm. Of course, during the downswing, there can be some left arm abduction during the initial torso rotation than eventually becomes greater. A human swing is largely a triple pendulum (torso, arm, club via wrists) and, in a less major sense, is a quadruple pendulum if the straightening of the right arm is added, which creates additional travel of the hands.
A swing where adduction is not at its maximum is simply a shorter backswing where the same sequence of torso then arm can be used.
S
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Post by utahgolfer on May 1, 2020 2:53:47 GMT -5
Hi DG,
The robot has no shoulder turn or torso rotation, and only simulates independent left arm motion. It is obviously good at testing golf shafts, but can it serve as a proxy for the human body?
PA#4, 2, and 3 involve the left arm, forearms, and wrists, but function with a pivot running in the background. How does it all ideally interact?
UG
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Post by dubiousgolfer on May 1, 2020 7:47:02 GMT -5
Thanks S/UG Yes, unsure why I thought Iron Byron was mirroring a TGM swinging action . On reflection , I sort of touched on this subject about pivot driven vs left arm (shoulder girdle) release of PA#4 in a previous thread. newtongolfinstitute.proboards.com/thread/681/why-pivot-classified-power-accumulator?page=1Apologies to all, especially Dr Mann, but I seem to be forgetting my own previously answered posts (my memory is not so good these days). DG PS. In that link above is the picture of a 2nd robot with an offset shoulder. I may have thought that represented a TGM swinging action (but I don't think it's an Iron Byron model). Actually the other robot with the offset shoulder is 'PING MAN' and I think its trying to replicate some of the shoulder socket movement in a real golfers swing. "PING’s swing robot has an interesting history. The first generation of PING’s swing robot was named Mr. PING and was designed by PING founder Karsten Solheim in the mid-1970’s. He decided to design his own after testing his clubs on other swing robots of the day. He wanted to design a robot that would swing more like a real golfer, which incorporated a free wrist and a shoulder. This design allowed for an upward motion of the lead shoulder at impact and an inertially-controlled swing path that did a great job aligning with the natural swing of a player. "Still unsure whether this offset shoulder makes it any different to the Iron Byron Dave Tutelman's says the following on his website: "The PingMan robot has an offset "shoulder". That is, the arm does not extend from the center of rotation, but rather from the edge of the shoulder "plane". This is claimed to add a level of realism other robots don't achieve. I will agree if the shoulder joint moves with respect to the driving shoulder disc during the downswing. If not, then the actual performance is the same as a rigid arm from the center of rotation."Strange that I cannot find any info on how it works but it looks like its an equivalent of a golfer using mostly shoulder girdle torque (ie. torque via that offset 'shoulder' joint section) to release PA#4 while its also being rotated around that central large hub section to change its shoulder 'joint' path (ie. and maybe induce 'some PA#4' and PA#2 release via D'Alemberts principle). Imho, it's basically a double pendulum to be honest just like Iron Byron.
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