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Post by dubiousgolfer on Jan 7, 2019 10:41:33 GMT -5
Dr Mann I have been thinking a bit more deeply about Dave Tutelman's diagrams below regarding forward bend of shaft means a negative torque at the hands (ie. hands cannot keep up with the angular velocity of the club). But when I looked at his video below , it basically confirms by experiment that the 'forward' bend of the shaft does not rotate with the rotation of the shaft around its longitudinal axis. So even though physics says that the rear hand cannot add more positive torque (in the direction where there is forward bend of the shaft) , there is nothing to stop the right hand from increasing the 'conical path' linear velocity of the clubhead by using PA#3 pressure forces (not aligned with the forward bend of the shaft). The PA#3 action would be analogous to Dave Tutelman turning that 'spin indexer' handle. I understand that you regard PA#3 as being a 'club squaring action' rather than a 'Power Accumulator' to increase clubhead speed , but if some golfers did have strong rotational forearm muscles, then could those same golfers 'theoretically' increase their linear clubhead speed using a very active PA#3 ? Although I can imagine a golfer doing this (with a weak/neutral grip) might succumb to a 'full roll' hand release action with a high ROC in the immediate impact zone area. On reflection, the size of the PA3 angle will also impact how much linear CHS could be generated because of the increased MOI . Further, the conical angular velocity caused by any Ryke effect might also lessen the affect of PA#3 release (ie. if conical angular velocity of club too fast for the hands one would need to apply even more PA3 positive torque to increase linear CHS). DG
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Post by imperfectgolfer on Jan 9, 2019 10:24:42 GMT -5
Dr Mann I have been thinking a bit more deeply about Dave Tutelman's diagrams below regarding forward bend of shaft means a negative torque at the hands (ie. hands cannot keep up with the angular velocity of the club). But when I looked at his video below , it basically confirms by experiment that the 'forward' bend of the shaft does not rotate with the rotation of the shaft around its longitudinal axis. So even though physics says that the rear hand cannot add more positive torque (in the direction where there is forward bend of the shaft) , there is nothing to stop the right hand from increasing the 'conical path' linear velocity of the clubhead by using PA#3 pressure forces (not aligned with the forward bend of the shaft). The PA#3 action would be analogous to Dave Tutelman turning that 'spin indexer' handle. I understand that you regard PA#3 as being a 'club squaring action' rather than a 'Power Accumulator' to increase clubhead speed , but if some golfers did have strong rotational forearm muscles, then could those same golfers 'theoretically' increase their linear clubhead speed using a very active PA#3 ? Although I can imagine a golfer doing this (with a weak/neutral grip) might succumb to a 'full roll' hand release action with a high ROC in the immediate impact zone area. On reflection, the size of the PA3 angle will also impact how much linear CHS could be generated because of the increased MOI . Further, the conical angular velocity caused by any Ryke effect might also lessen the affect of PA#3 release (ie. if conical angular velocity of club too fast for the hands one would need to apply even more PA3 positive torque to increase linear CHS). DG I cannot fathom how the release of PA#3 can significantly increase clubhead speed. Surely, the amount of increased clubhead speed is derived from multiplying a <90 degree change in the clubface angle that happens between P6 and P7 X the distance from the hosel to the sweetspot. I am not good at golf physics, but I presume that it can only contribute a few miles per hour to clubhead speed. Also, any attempt to actively release PA#3 pre-impact will not predispose to a full-roll hand release action (which is due to external rotation of the left humerus) through impact and it will predispose to a rolling subtype of non-DH hand release action through impact. Jeff.
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Post by dubiousgolfer on Jan 9, 2019 21:52:14 GMT -5
Many thanks Dr Mann - got my hand release actions confused. So a rolling subtype of a non-DH hand release action could be any of the below?
Crossover Hand Release Action Roller Release Hand Action/Flip Roll Flip Release Hand Action
Out of interest , how would one define Jamie Sadlowski's hand release action ?
DG
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Post by imperfectgolfer on Jan 10, 2019 10:10:34 GMT -5
Many thanks Dr Mann - got my hand release actions confused. So a rolling subtype of a non-DH hand release action could be any of the below? Crossover Hand Release Action Roller Release Hand Action/Flip Roll Flip Release Hand Action Out of interest , how would one define Jamie Sadlowski's hand release action ? DG There are three subtypes of non-DH hand release action - i) rolling subtype (which includes a hand crossover release action and the roller hand release action [which are both exaggerated forms of a rolling subtype]) and it is due to excessive left forearm supination happening between P7 and P7.2; ii) flipping subtype, which is due to left wrist extension; and iii) flip-rolling subtype, which combines elements of both i) and ii). Jamie Sadlowski is a DHer because his clubshaft does not bypass his left arm between P7 and P7.2, and he only flip-rolls his left wrist after P7.2 (with the flipping element being the major element). By contrast, Domenic Mazza is a DHer who rolls after P7.2 with very little left wrist extension. Jamie Sadlowski Domenic Mazza Jeff.
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Post by dubiousgolfer on Jan 10, 2019 20:47:45 GMT -5
Many thanks Dr Mann
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Post by dubiousgolfer on Feb 1, 2024 11:34:41 GMT -5
I am going to revisit this post because of Dr Sasho MacKenzies forward dynamic model research results in his articles: Club position relative to the golfer’s swing plane meaningfully affects swing dynamics A three-dimensional forward dynamics model of the golf swingSIM1 - A simulated golf swing that didn't use any forearm supination torque but where the club was squared at impact by passive torques - clubhead speed 36.2 m/s = 81 mphh SIM3 - A simulated golf swing that did use active forearm supination torque to square the club at impact - clubhead speed 44.1 m/s = 99 mph SIM1 downswing started with the clubs COM positioned 7.3 cms below the lead arm swing plane. The torso/shoulder/wrist torque generators were switched on , while the whole arm torque generator for rotation about its longitudinal axis was switched off .The model was able to create a swing where the clubface was square at impact with clubhead velocity components in the x,y,z axis as shown below. I think the ball trajectory would have been a fade looking at the table below . SIM3 downswing was initiated with the shaft perfectly within the golfer’s swing plane (ie. COM positioned 1.4 cm below lead arm swing plane) and the optimisation was conducted with all the torque generators available to supply energy to the system (ie. including the arm rotation torque generator). Again, the model was able to create a swing where the clubface was square at impact with clubhead velocity components in the x,y,z axis as shown below. I think the ball trajectory would have been a draw looking at the table below. The results for SIM3 was the same for SIM5 (which was setup with 10 degree steeper lead arm swing plane) and the graphs showing the torques are below Fig 6. The graphs look very similar to another optimised swing by Dr Mackenzie in a different research article where he first introduced his forward dynamics model (see Fig 7) that had a clubhead speed of 94.3 mph at impact. SMK said "the clubhead path employed an inside-to-outside clubhead path, which is characteristic of expert golfers". The interesting point is that the forearm/arm generator in 'SIM3 & SIM5' switched on at about P5 and ramped up to a maximum torque of about 25 Nm at about P5.7 . This torque was applied to the whole mass of the 'arm/hand/club unit' but did not tumble the club over in any OTT fashion (or like Mike Malaska move). The club path at impact still mirrored that of an expert golfer. The models torque capacity for rotation of the lead arm was increased over and above the capability of human muscles associated in the shoulder area. This was to cater for a missing trail arm capability. The important point to note was that active supination torque in SIM3 & SIM5 seemed to be responsible for the increase in clubhead speed of 18 mph compared to SIM1 (ie. no supination torque). Doesn't this imply that PA#3 is not just a club squaring mechanism but can create a significant increase in clubhead speed if timed properly with all the other kinematic movements during the downswing? DG
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Post by dubiousgolfer on Feb 1, 2024 12:01:29 GMT -5
I seem to also have a copy of an email I sent to SMK back in 2021, where I asked him the following (but he never replied back with any answers).
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Dear Dr MacKenzie
I was wondering whether you had similar optimal torque graphs for Sim1 and Sim3 ?
In your article Sim3 clubhead speed at impact was 18% greater than Sim1.
You then stated the below later in your article:
"which indicates as to how much active rotation of the forearm from a muscular torque can contribute to clubhead speed"
But did SIM1 show less optimised 'Torso/Shoulder/Wrist' torque generation values than SIM3 or SIM5? Could the differences in the latter torque generator values also account for why SIM1 clubhead speed was 18% less than SIM3/SIM5 at impact?
Is there any means to identify what % of that clubhead speed increase for SIM3 and SIM5 was just due to active forearm muscular torque?
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So still some questions about whether PA#3 was a direct cause for the increase in clubhead speed for SIM3/5.
DG
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