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Post by nmgolfer on Jan 8, 2012 16:41:48 GMT -5
Jeff, To make it clear, I'm giving up on you. I don't believe you're capable of understanding release physics. And you're obsessed with the incoherent musing of a Boeing drafter that like you knew little or no physics. Thats fine... its a free world but to me you look like Don Quixote. I don't know how many time a person must say something before it sinks in ... THE FORCE IS DIRECTED INWARD BECAUSE ITS PROPORTIONAL TO THE VELOCITY OF THE HANDS SQUARED (RAISED TO THE POWER OF 2). Hand velocity increases all the way to impact. BTW there is no SN hub path model. There is nothing theoretical about what he says. Its simple measurements with the kinetics backed out of them using the principles Isaac Newton came up with centuries ago. Do you consider Newton's equations of motion theoretical too? The model is a biometric model of the body.... has nothing to do with the forces and moments on the club. nmg, You wrote-: "Frankly it sounds to me like Nesbit is saying it right. I think you still do not understand it. (I tried like hell to explain the mechanics of release to you years ago and am dismayed to see that it apparently never sunk in... I give up)" I am glad that you are giving up - because I think that you seemingly have nothing useful to contribute other than your original idea about the hand release (which I think is rational). Jeff.
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Post by nmgolfer on Jan 8, 2012 16:56:33 GMT -5
Jeff...
It sounds like you fault Nesbit for not presenting some grand unified theory of the golf swing but clearly that was not his objective. He was discussing the force and moment on the club at various stages of the downswing based on his measurments. He does not say where the force comes from becuase its patently obvious: Club is connnected to golfer's hands at the grip. THE GOLFER is applying that force and torque.
I think there's probably nobody that knows more about the golf stroke than Nesbit and that includes you. Pick P.whatvere... can you tell me what work the average golf's hip are doing? What work his shoulders are doing? Nesbit can. He has a validated model. All you have are untested theories.
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Post by imperfectgolfer on Jan 8, 2012 17:23:11 GMT -5
Natep, Posting that diagram from the Miura article and likening it to the SN/BM rotation-about-the-coupling point model only demonstrates to me that you lack the ability to discriminate between the two. Consider Miura diagram. The Miura model is based on a double link model, which works according to the same principles as a driven double pendulum swing model. Note that he draws the arrows in the same direction as the hand arc path in the entire downswing (which makes sense) - and he doesn't inexplicably draw an arrow in a progressively more inward direction like SN - and that changing left hand movement along the hand arc path causes the club to CF-release according to the nmg explanation (Vclubhead = Vhands + V rel). That CF-releasing force is the tangential force that causes the club to release. It is very different to the SN model where he states that the club release phenomenon is due to the right hand applying a push-force on the aft side of the grip and rotating the club around the coupling point, which is the basis for BM's RACP release model. Secondly, Miura shows a radial force developing in the later downswing that is directed centrally, and that is due to elevation of the left shoulder socket in the later downswing. That radial-directed force produces parametric acceleration, and I do not disagree with the idea of there being a supplementary radially-directed force that produces radial acceleration. Note that he only draws arrows moving centrally starting at about the P6.5-P6.7 position. How large is that radial force and what effect does it have on clubhead speed? Here is another diagram from the Miura article. Note that he has modified his double-link model by adding a linear actuator that can pull the grip end of the upwards (centrally). He then shows how much force is applied by that linear actuator in the late downswing in his left-upper corner diagram. That centrally-directed force (due to the linear actuator) peaks at impact, and it is the only force working on the shaft at impact - because the club-releasing (tangential) force dissipates at impact in a double-link model due to the fact that the club has now caught up to the central arm (left arm). Note, in the right-sided graph, that he shows that it increases clubhead speed by ~5%. I have no problem with the Miura model because it is consistent with what happens in reality in a swinger's action. By contrast, The SN model i) posits a "force" (which is not precisely defined) that is inexplicably inward directed in the mid-late downswing - prior to the parametric phenomenon becoming operant and ii) it posits a positive torque force around the coupling point being used to release the club. I do not think that the SN model applies to a swinger, and it is really only applicable to a swing-hitting procedure. Finally, both the Miura model and the SN model were designed to maximize clubhead speed at impact and they were not designed to ensure that the clubhead doesn't bypass the left wrist between P7 and P7.2. I obviously believe that the "optimum" swing model for a golfer should ensure that the clubface remains square to the target throughout the entire immediate impact zone - from the P6.9 position to the P7.2 position - as demonstrated by Tiger Woods who still has a FLW and intact LAFW at the P7.2 position. . Jeff.
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Post by imperfectgolfer on Jan 8, 2012 17:35:01 GMT -5
nmg,
You wrote-: "He was discussing the force and moment on the club at various stages of the downswing based on his measurments. He does not say where the force comes from becuase its patently obvious: Club is connnected to golfer's hands at the grip. THE GOLFER is applying that force and torque."
SN discussed this issue during his presentation. He stated that he used 3-D measurements to measure the movement of body parts in many individual golfers. Then he used inverse engineering principles to devise a computer model that could replicate a golfer's body/arm movements and his model was also based on estimated torques needed to replicate the club's release phenomenon. His model does that correctly - but it only replicates a swing-hitter's swing action, and not a swinger's swing action, because he automatically presumes that a golfer will apply a positive torque with the right hand around the coupling point to induce/facilitate the club release phenomenon (as BM recommends for his swing-hitting action). I definitely agree that it is possible to play golf as a swing-hitter, but I much prefer the swinging technique that maintains an intact LAFW/FLW all the way to the P7.5 position. The SN model doesn't deal with what happens between the P7 position and the P7.5 position, and I think that it is critically important to ensure that the FLW/clubface remain square to the target beyond the P7 position, which is why I promote the intact LAFW/FLW swing technique.
Jeff.
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Post by nmgolfer on Jan 8, 2012 19:31:01 GMT -5
Jeff,
swinger/hitter:
Nesbit's model assumes no such thing (show me evidence to the contrary... where in his papers he states this). Based on measured motion the model tells him what forces and torques were required to generate it. Given the measured motion he uses Newton's laws to determine what forces and torques produced it. Its not some whacked out "driven" model like you've seen from all others including Jorgenson, mandrin and zick.
There is no "tangential" force... there is no "normal" force... there is only THE FORCE which causes the release and its mostly directed inward otherwise the path would not be an arc (contracting spiral actually). The fact that the line of action of THE FORCE does not go through the CG of the club is what cause's the release. Again release has NOTHING to do with some "tangential force" you are imagining and please stop attributing that nonsense, which I certainly do not agree with, to me. Thank you for your cooperation.
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Post by imperfectgolfer on Jan 8, 2012 19:51:37 GMT -5
nmg,
You wrote-: "There is no "tangential" force... there is no "normal" force... there is only THE FORCE which causes the release and its mostly directed inward otherwise the path would not be an arc (contracting spiral actually). The fact that the line of action of THE FORCE does not go through the CG of the club is what cause's the release. Again release has NOTHING to do with some "tangential force" you are imagining and please stop attributing that nonsense, which I certainly do not agree with, to me. Thank you for your cooperation."
The idea that the hand arc path contracts spirally is a figment of your imagination. The hand arc path in a swinger is primarily determined by the combination of two phenomena - i) the 3-D movement of the left shoulder socket in space in the downswing and ii) the release of PA#4. There is also a parametric acceleration element of variable degree added to the primary mix.
The term "tangential force" applies to the force of club release (a force working in a non-radial direction) - whether it is produced by a positive wrist torque or whether it is due to a CF-release action (Vclubhead = V hands + Vrel). If you do not like the term, you are not obliged to use it. Finally, I will interpret the CF-release phenomenon in any way that I want - whether you believe, or don't believe, that I am interpreting the CF-release phenomenon correctly. I no longer respect your knowledge in this arena, and I feel no need to gain your approval on how I personally choose to describe golf swing mechanics/biomechanics.
You also wrote-: "Nesbit's model assumes no such thing (show me evidence to the contrary... where in his papers he states this). Based on measured motion the model tells him what forces and torques were required to generate it. Given the measured motion he uses Newton's laws to determine what forces and torques produced it."
I agree that this is how he presented it in his papers. However, that is not how he presented it in his presentation at the BM AntiSummit II. Any forum member who has viewed the video can verify this fact - that SN went along with BM who claimed that a golfer applies positive wrist torque with the right hand around the coupling point, and that all golfers are pulling-and-pushing at the same time.
Jeff.
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Post by nmgolfer on Jan 8, 2012 23:27:46 GMT -5
Jeff,
You have not demonstrated the you understand even the most basic principles of physics. Torques don't produce force and the tangential component of the force is not responsible for release. You asked for comment and when you didn't like the answer you began dishing out insults. Very immature of you to do that. I've lost all respect for you as a person and researcher of the golf swing and frankly I'm sorry I ever gave you a minute of my time.
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Post by nmgolfer on Jan 8, 2012 23:33:31 GMT -5
Ps I still think very highly of sn's work. There is gold there for people who know how to find it and don't spend their time tilting at windmills.
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Post by imperfectgolfer on Jan 9, 2012 0:23:29 GMT -5
nmg,
You wrote-: "Torques don't produce force and the tangential component of the force is not responsible for release."
You seem to be incapable of understanding what I have stated. I never stated that "torques produce a force". I believe that a force applied in a rotary manner applies a torque. I also never stated that the "tangential component of the force is reponsible for the release". You are mixing up cause-and-effect. I believe that the tangential component is the result of the release - and the term "tangential" applies to any force that causes the club to move tangential to the clubhead arc after the club is released (rather than radial to the clubhead arc). In a swing-hitter's action, the force causing the club to move tangentially is due to a torque applied around the coupling point by the right hand, while in a swinger's action the club gets to move tangentially as a result of the CF-release action (as a result of the club gaining angular momentum due to Vclubhead = Vhands + Vrel).
You also wrote-: "I still think very highly of sn's work." So do I - as he presented his work in a peer-reviewed scientific journal. When I talked about "junk science" with respect to his work, I am only referring to his BM-manipulated presentation at the BM AntiSummit II. BM constantly interjected himself into SN's explanations and SN haplesssly (and perhaps unknowingly) allowed his scientific work to be manipulated into a biased presentation that I label "junk science".
You also wrote-: "I've lost all respect for you as a person and researcher of the golf swing and frankly I'm sorry I ever gave you a minute of my time."
I understand your position, and I am happy to reciprocate your sentiments in kind. I wish you well in any future endeavors to educate other forum members and other golfers re: golf swing mechanics/biomechanics.
Jeff.
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Post by imperfectgolfer on Jan 9, 2012 10:57:37 GMT -5
This what BM posted in his "new release" thread today when asked "what's the new release".
BM wrote-:
"I have NEVER CALLED IT a "New" Release.
The video is called IDEAS about The Release.
But....
To answer your "questions".....
What's new is ACTUAL SCIENCE is being used to describe, decipher, and TEACH the forces the golfer puts on the ball from the top of the swing through impact.
What the fuss is all about is how DIFFERENT the information is that the pull the handle through or pushy the handle through swings commonly taught the last 20 years. Importantly, the "idea" that the club should NEVER PASS THE LEFT ARM through impact was exposed for what it is—a guess.
To achieve it,from the top pull the club in the direction of the shaft CONTINUOUSLY as you begin to straighten your right arm (and your left arm slightly if it was bent) out away from you away from the target WHILE you preserve as much of your FULL shoulder turn as you can. About half-way down, WHILE YOUR CHEST IS FACING YOUR HANDS, use your right shoulder and right arm to re-position themselves to help you rotate the club about a point between your hands. When the club has some speed from this rotation, and the clubhead is level or slightly lower than your hands, use everything you have to pull the grip off of the club as our hips move left, open, and you lose all of your forward bend."
I bold-highlighted a series of statements - and BM got SN to provide scientific justification for those personal opinions by manipulating things in his standard dog-and-pony show manner at the BM AntiSummit II.
Note that BM also wrote-: "Importantly, the "idea" that the club should NEVER PASS THE LEFT ARM through impact was exposed for what it is—a guess."
He calls the idea of maintaining an intact LAFW/FLW well beyond impact in order to keep the clubface square to the target until at least the P7.2 position a "guess".
Phew! It's definitely different strokes for different folks!
Jeff.
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Post by imperfectgolfer on Jan 9, 2012 14:25:45 GMT -5
I have just completed a fruitful Skype video communication with Sasho MacKenzie.
He agrees with my personal assessment of the SN hub path computer model. The SN model (as described in SN's paper) only predicts where the hands should be along the hand arc path at every moment of the downswing and it also predicts what torque forces are required to release the club. It doesn't imply that the torque forces that release the club are due to the right hand applying a torque force around the coupling point - rather than being due to a CF-releasing force (V clubhead = V hands + V rel). In other words, if the hands follow the identical hand arc path, then it doesn't matter whether the left hand (which grips the club) is pulled forward, or pulled-and-pushed forward, or only pushed forward. The club only experiences a body-created "force" that causes the left hand to pull the club along the entire length of the downswing hand arc path. Sasho therefore also agreed with me that any "force" moving the club in the downswing has to work via the 3-D movement of the left hand along the entire course of the hand arc path, and that the "force" arrows must therefore be drawn tangential to the hand position at every instantaneous moment of the downswing - as Miura demonstrates in this diagram (ignoring the last 5 centrally-directed arrows that are due to the addition of a parametric acceleration force).
Sasho also explained why the only "force" operating at impact is a normal force (centrally directed force due to the left shoulder moving upwards thereby producing a parametric acceleration force). His explanation is that although the left hand is still moving forward fast through impact, it is not applying a tangential force to the club at impact because the club is moving too fast at that stage of the downswing to be further accelerated by forward motion of the left hand. An useful analogy is cycling a bicycle down a hill - when the wheels reach a certain speed, then one cannot produce further "force" via spinning the foot pedals to make the wheels travel faster. That explanation makes sense to me. In other words, the forward motion of the FLW between P7 to P7.5 can maintain an intact FLW, but it cannot biomechanically make the club move faster if it has already reached its maximum speed at impact - because it is biomechanically impossible for the left arm to move fast enough to achieve further clubhead speed.
Jeff.
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Post by natep on Jan 9, 2012 14:36:08 GMT -5
So Mackenzie says Nesbit's full of it??
I'd love to see that in writing.
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Post by natep on Jan 9, 2012 14:47:27 GMT -5
If the club is moving too fast thru impact for the laft arm to apply force then how is the left wrist going to stay flat?? You're so wrong on all of this its not even funny. I have no idea why you're so obsessed with validating TGM swinging when everyone else in the world already understands that the right hand torques the club on the downswing. NOBODY can swing as fast with one arm as they can with two.
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Post by imperfectgolfer on Jan 9, 2012 14:50:30 GMT -5
Natep,
You wrote-: "So Mackenzie says Nesbit's full of it?"?
Nope. He stated that BM's personal interpretation of the SN model is a selective interpretation of how the "forces" are generated to fit in with the SM model's predictions regarding "forces". He stated that the SN model is not only fully compatible with BM's swing-hitting action, but that it is equally compatible with a swinger's action. In other words, SN's model (as presented in his paper) is bias-free. It predicts the "forces" needed to move the left hand along the hand arc path and it specifies the "torque forces" need to release the club, but it doesn't mandate how those force must be produced by a golfer . A golfer can produce those same "forces" via a swinger's action, or via a swing-hitter's action - if they generate an identical hand arc path.
Jeff.
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Post by imperfectgolfer on Jan 9, 2012 15:01:12 GMT -5
Natep, You wrote-: "If the club is moving too fast thru impact for the laft arm to apply force then how is the left wrist going to stay flat?? You're so wrong on all of this its not even funny. I have no idea why you're so obsessed with validating TGM swinging when everyone else in the world already understands that the right hand torques the club on the downswing. NOBODY can swing as fast with one arm as they can with two." I asked Sasho those questions. He states that he generates more clubhead speed with a two-armed swing (110 mph versus 95mph) because he can release PA#3 more efficiently in the late downswing. He states that the addition of the right arm doesn't increase his speed of release of PA#4. The left wrist remains flat from P7 to P7.5 in most professional golfers because ball impact slows down the clubhead while they continue to actively complete their release of PA#4 (which only ends roughly at the P7.5 position if they do not stall through impact). Here is Freddie Couples. In the second image he is maintaining a FLW because his left hand (and FLW) doesn't stall through impact. Jeff.
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