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Post by dubiousgolfer on Aug 13, 2019 5:37:19 GMT -5
Dr Mann Been reading your Tyler Ferrell Review and looking at this Electromyography Chart that Tony Luczak published. Can EMG differentiate between the type of muscle contraction (Isometric, Eccentric , Concentric)? If not, I cannot understand how one can discern what these muscles are actually doing during the golf swing (ie. are they being used to accelerate or decelerate movement?). DG
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Post by imperfectgolfer on Aug 13, 2019 6:44:16 GMT -5
Dr Mann Been reading your Tyler Ferrell Review and looking at this Electromyography Chart that Tony Luczak published. Can EMG differentiate between the type of muscle contraction (Isometric, Eccentric , Concentric)? If not, I cannot understand how one can discern what these muscles are actually doing during the golf swing (ie. are they being used to accelerate or decelerate movement?). DG EMG simply measures the degree of strength of muscular contraction in terms of its electrical signal - compared to the electrical signal produced by a maximum contraction (often established at baseline by performing a maximum isometric contraction against resistance). However, it does not measure whether that muscular activity is producing an isometric contractile event versus an isotonic contractile event. Jeff.
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Post by dubiousgolfer on Aug 14, 2019 7:45:51 GMT -5
Many thanks Dr Mann
I've just found this video below (especially the MYSWING 3D analysis shown later ) which seems to suggest that PA#4 can be even more loaded during transition. Is this a fair description of left arm adduction's importance in generating torque in the early downswing to increase hand/clubhead speed during the 'straighter path ' before release (if we disregard Zach Allen's opinion regarding ground forces)? Some of the closeups of the right shoulder scapula doesn't show much movement with regards retraction/protraction but could there be 'isometric' contraction from P4-P5?
For example, if we looked at Tony Luczak's chart above for the 'forward swing' from P4-P6, could the 3 right-sided muscles 'Subscapularis, Latissimus Dorsi, Pectoralis Major' be mainly Isometric contraction , while the left 'Subscapularis/Lattisimus Dorsi' be an 'Isotonic' contraction?
DG
PS, I have raised the below question to Mr Luczak but he deleted my previous 'you-tube' comment about whether he has used Dr Steven Nesbit research in his modelling software.
"Hi Tony - Unsure why my comment about Dr Steven Nesbit was deleted as I'm only concerned with the physics being used here. Your EMG charts do indeed show higher readings for muscular contraction in the right sided muscles, lats , pecs, etc from P4-P6 but you cannot confirm whether they are isometric or isotonic contractions (or a mix during that swing phase). So which muscles are actually producing most of the isotonic (concentric contractions) to create hand speed in the 'Forward Swing' phase?
Further , if you are using algorithms based on Dr Steven Nesbitt modelling research , especially the equations he used to map shaft bend , then you must already be aware that there are group of golf scientists & biomechanic experts who think he has made some errors. Especially the damping factors in the differential equations for the interaction between the hands and club grip. If you use Dr Nesbits research data , it will infer that there is positive torque being produced by the hands but really it should be 'negative torque' . This is a very dangerous for golf instruction to the multitudes if the science research is found to be flawed. All it will do is cause bigger problems and more frustration for learning golfers and drive them away from the game."
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Post by imperfectgolfer on Aug 14, 2019 13:43:06 GMT -5
Many thanks Dr Mann I've just found this video below (especially the MYSWING 3D analysis shown later ) which seems to suggest that PA#4 can be even more loaded during transition. Is this a fair description of left arm adduction's importance in generating torque in the early downswing to increase hand/clubhead speed during the 'straighter path ' before release (if we disregard Zach Allen's opinion regarding ground forces)? Some of the closeups of the right shoulder scapula doesn't show much movement with regards retraction/protraction but could there be 'isometric' contraction from P4-P5? For example, if we looked at Tony Luczak's chart above for the 'forward swing' from P4-P6, could the 3 right-sided muscles 'Subscapularis, Latissimus Dorsi, Pectoralis Major' be mainly Isometric contraction , while the left 'Subscapularis/Lattisimus Dorsi' be an 'Isotonic' contraction? DG PS, I have raised the below question to Mr Luczak but he deleted my previous 'you-tube' comment about whether he has used Dr Steven Nesbit research in his modelling software. "Hi Tony - Unsure why my comment about Dr Steven Nesbit was deleted as I'm only concerned with the physics being used here. Your EMG charts do indeed show higher readings for muscular contraction in the right sided muscles, lats , pecs, etc from P4-P6 but you cannot confirm whether they are isometric or isotonic contractions (or a mix during that swing phase). So which muscles are actually producing most of the isotonic (concentric contractions) to create hand speed in the 'Forward Swing' phase? Further , if you are using algorithms based on Dr Steven Nesbitt modelling research , especially the equations he used to map shaft bend , then you must already be aware that there are group of golf scientists & biomechanic experts who think he has made some errors. Especially the damping factors in the differential equations for the interaction between the hands and club grip. If you use Dr Nesbits research data , it will infer that there is positive torque being produced by the hands but really it should be 'negative torque' . This is a very dangerous for golf instruction to the multitudes if the science research is found to be flawed. All it will do is cause bigger problems and more frustration for learning golfers and drive them away from the game." I am very sceptical that a a few degrees of increased left arm adduction at the transition to the downswing has any significant effect in terms of the amount of swing power ultimately derived from the release of PA#4. Jeff.
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Post by dubiousgolfer on Aug 15, 2019 6:32:13 GMT -5
Many thanks Dr Mann I've just found this video below (especially the MYSWING 3D analysis shown later ) which seems to suggest that PA#4 can be even more loaded during transition. Is this a fair description of left arm adduction's importance in generating torque in the early downswing to increase hand/clubhead speed during the 'straighter path ' before release (if we disregard Zach Allen's opinion regarding ground forces)? Some of the closeups of the right shoulder scapula doesn't show much movement with regards retraction/protraction but could there be 'isometric' contraction from P4-P5? For example, if we looked at Tony Luczak's chart above for the 'forward swing' from P4-P6, could the 3 right-sided muscles 'Subscapularis, Latissimus Dorsi, Pectoralis Major' be mainly Isometric contraction , while the left 'Subscapularis/Lattisimus Dorsi' be an 'Isotonic' contraction? DG PS, I have raised the below question to Mr Luczak but he deleted my previous 'you-tube' comment about whether he has used Dr Steven Nesbit research in his modelling software. "Hi Tony - Unsure why my comment about Dr Steven Nesbit was deleted as I'm only concerned with the physics being used here. Your EMG charts do indeed show higher readings for muscular contraction in the right sided muscles, lats , pecs, etc from P4-P6 but you cannot confirm whether they are isometric or isotonic contractions (or a mix during that swing phase). So which muscles are actually producing most of the isotonic (concentric contractions) to create hand speed in the 'Forward Swing' phase? Further , if you are using algorithms based on Dr Steven Nesbitt modelling research , especially the equations he used to map shaft bend , then you must already be aware that there are group of golf scientists & biomechanic experts who think he has made some errors. Especially the damping factors in the differential equations for the interaction between the hands and club grip. If you use Dr Nesbits research data , it will infer that there is positive torque being produced by the hands but really it should be 'negative torque' . This is a very dangerous for golf instruction to the multitudes if the science research is found to be flawed. All it will do is cause bigger problems and more frustration for learning golfers and drive them away from the game." I am very sceptical that a a few degrees of increased left arm adduction at the transition to the downswing has any significant effect in terms of the amount of swing power ultimately derived from the release of PA#4. Jeff. Dr Mann There is a possible 'tenuous' explanation for why there could be an increase in swing power and that is something I read on Tutelmans website. "It is probably worth mentioning here that, when I was working on my article on mathematical models of the swing, something about Sasho MacKenzie's model clicked. I refer now to his swing optimized for clubhead speed. For the first part of the downswing, the muscular torque is all torso. There is no shoulder torque, the torque that separates the left arm from the chest. That means that the left arm is being driven by what MacKenzie calls "passive tissue interaction" with the chest; the chest is pushing the left arm around. That is further confirmation that this does in fact increase clubhead speed, because a computer optimization of one of the better swing models recommends it." Tutelman then shows a diagram below where the radius of the left arm is shortened because the fulcrum at the left shoulder joint is effectively replaced (from P4-P5) by 'passive tissue interaction' point between chest and upper arm (ie. a new 'temporary' fulcrum point - see green Line compared to blue line). The formula for Torque is below T = Force x radius Therefore for a given shoulder Torque , if you shorten the radius, the Force (at the hands ) gets larger. The larger the Force exerted on the hands/grip , the greater the clubhead speed (during the straighter path of the early downswing). I must admit that I am not convinced about the above explanation because this would mean that the 'Force' direction on the hands/grip would be mostly 'outwards' perpendicular to the axis of rotation of the 'shoulder torque'. So it might increase clubhead speed in a 'horizontal abduction direction of the left arm' which I think would cause an OTT clubhead path. But could it help a golfer create clubhead speed (without an OTT move) who might have an 'On Plane' swing via the TSP? Not sure. DG PS. Dave Tutelman said he achieved more speed using 'passive tissue interaction' and I suspect this is the same technique he was using in his you-tube swing below.
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Post by imperfectgolfer on Aug 15, 2019 9:06:54 GMT -5
I am very sceptical that a a few degrees of increased left arm adduction at the transition to the downswing has any significant effect in terms of the amount of swing power ultimately derived from the release of PA#4. Jeff. Dr Mann There is a possible 'tenuous' explanation for why there could be an increase in swing power and that is something I read on Tutelmans website. "It is probably worth mentioning here that, when I was working on my article on mathematical models of the swing, something about Sasho MacKenzie's model clicked. I refer now to his swing optimized for clubhead speed. For the first part of the downswing, the muscular torque is all torso. There is no shoulder torque, the torque that separates the left arm from the chest. That means that the left arm is being driven by what MacKenzie calls "passive tissue interaction" with the chest; the chest is pushing the left arm around. That is further confirmation that this does in fact increase clubhead speed, because a computer optimization of one of the better swing models recommends it." Tutelman then shows a diagram below where the radius of the left arm is shortened because the fulcrum at the left shoulder joint is effectively replaced (from P4-P5) by 'passive tissue interaction' point between chest and upper arm (ie. a new 'temporary' fulcrum point - see green Line compared to blue line). The formula for Torque is below T = Force x radius Therefore for a given shoulder Torque , if you shorten the radius, the Force (at the hands ) gets larger. The larger the Force exerted on the hands/grip , the greater the clubhead speed (during the straighter path of the early downswing). I must admit that I am not convinced about the above explanation because this would mean that the 'Force' direction on the hands/grip would be mostly 'outwards' perpendicular to the axis of rotation of the 'shoulder torque'. So it might increase clubhead speed in a 'horizontal abduction direction of the left arm' which I think would cause an OTT clubhead path. But could it help a golfer create clubhead speed (without an OTT move) who might have an 'On Plane' swing via the TSP? Not sure. DG PS. Dave Tutelman said he achieved more speed using 'passive tissue interaction' and I suspect this is the same technique he was using in his you-tube swing below. I don't believe that there is significant chest-left arm contact during the P4 and P5 time period that would move the fulcrum point to the chest wall in most pro golfers - and I suspect that it is not a source of significantly increased torque being applied to the left arm in the plane of left arm abduction. Many pro golfers (eg. Tony Finau and Jon Rahm) do not even get their left arm so far back at P4 that it actually touches the chest wall far medially relative to their left shoulder socket. I noted from that DT-video that David Tutelman is a big-time flipper through impact. Jeff.
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Post by dubiousgolfer on Aug 16, 2019 7:57:19 GMT -5
Many thanks Dr Mann
I noticed in DT's practice swing that he uses a pitch elbow and he didn't release PA#2 as early as he did in his actual swing. In his actual swing he used a 'punch' elbow and released PA#2 very early .
One question I need to ask you.
If lead leg extends more vertically upwards rather than helps rotate the pelvis back and up (ie. after hip squaring phase), what effects could this have on the release of PA#4 ,PA#2 and PA#3 ?
More specifically , if you lateral shift your pelvis towards target while extending the lead leg in a more vertical direction, what would be the most likely swing fault that one expect to see? I'm also assuming a scenario that when a golfer does that pelvic lateral shift they are not necessarily shifting too much weight pressure on the lead hip joint when they extend the leg (ie. the left hip doesn't bypass the lead knee).
The reason I asked this is because of Milo's you tube video below and his opinion of cause and affect of that pupil golfers swing fault.
It looks like Milo has altered the pupils hand and arm release (plus moved from flat left wrist to a palmar flexed one- but only from P4-P5 I think!).
1st swing - elbow plane at impact, 'full roll - non-DH hand release', CF -arm release
Fixed swing - elbow plane at impact, 'No roll- DH hand release' , CP -arm release.
DG
PS. Difficult to really assess what is happening with the 1st swing without a face view.
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Post by imperfectgolfer on Aug 16, 2019 15:58:52 GMT -5
DG, You asked-: " More specifically , if you lateral shift your pelvis towards target while extending the lead leg in a more vertical direction, what would be the most likely swing fault that one expect to see?" I think that it may predispose to pushed shots or push-slices. If one shifts the pelvis left-laterally while straightening the left leg, then one will be braced against the left side but without an ability to open the pelvis and therefore the upper torso through impact because of a lack of counterclockwise rotation of the pelvis. Under those conditions, one cannot easily swing the arms inside-left through impact and that would predispose to pushed shots. It is also possible (under those same conditions), that a golfer will not release the left arm freely through impact and if the left arm stalls through impact it could predispose to left wrist flipping, which would cause a leftwards ball flight as a result of the flipping action. Jeff.
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Post by dubiousgolfer on Aug 17, 2019 5:53:18 GMT -5
Many thanks Dr Mann
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