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Post by dubiousgolfer on Jan 22, 2018 20:26:29 GMT -5
Dr Mann I have been viewing a few of Sasho McKenzies videos regarding Kinetics , Couples and Moment of Force , etc. vimeo.com/158419250In the above video from 6:05 -10:24 he states that at P4 (for a group of professional golfers) the 'Trail Hand' is applying a force UP in opposition to the lead hand. This is according to research done (by Japanese researcher Koike in 2006) using some instrumented handle that could measure forces being applied by each hand. He also states that at P4 this UP force is greater than the DOWN force and will cause a 'moment of force' in the clockwise direction which assists clubhead 'lag' in the downswing until club is vertical (mentioned in video below at 10:00 - 11:30) vimeo.com/158856998Question 1: Do you think this video is representative of how PGA golfers apply forces with the trail hand? Question 2 : If yes to question 1, can we explain this phenomenon from a TGM perspective, by assuming that this UP force is caused by applying PP1 from P4-P5? That extensor action, is keeping the left arm comfortably straight but also assisting in the production of lag?
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Post by imperfectgolfer on Jan 23, 2018 1:57:14 GMT -5
Dr Mann I have been viewing a few of Sasho McKenzies videos regarding Kinetics , Couples and Moment of Force , etc. vimeo.com/158419250In the above video from 6:05 -10:24 he states that at P4 (for a group of professional golfers) the 'Trail Hand' is applying a force UP in opposition to the lead hand. This is according to research done (by Japanese researcher Koike in 2006) using some instrumented handle that could measure forces being applied by each hand. He also states that at P4 this UP force is greater than the DOWN force and will cause a 'moment of force' in the clockwise direction which assists clubhead 'lag' in the downswing until club is vertical (mentioned in video below at 10:00 - 11:30) vimeo.com/158856998Question 1: Do you think this video is representative of how PGA golfers apply forces with the trail hand? Question 2 : If yes to question 1, can we explain this phenomenon from a TGM perspective, by assuming that this UP force is caused by applying PP1 from P4-P5? That extensor action, is keeping the left arm comfortably straight but also assisting in the production of lag? Unfortunately, I do not have the physics-knowledge to rationally critique Sasho's opinions on this topic. I saw that video years ago, and I contacted Sasho to ask how it is possible to supply that upforce when swinging with only the lead arm (and when there is no trail hand). He answered by stating that a different part of the lead palm was supplying that upforce. I am very sceptical of that explanation! I personally find his explanations based on the couple-force phenomenon (which are purely theoretical) very unconvincing. Steve Nesbit uses different theories to explain what is happening in terms of forces/torques being applied to the club handle and like Sasho's explanations, they are purely theoretical and therefore questionable/debatable. I have never learned anything useful/practical about how to biomechanically perform a full golf swing from either Sasho MacKenzie's or Steve Nesbit's theoretical work. Have you? Jeff.
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Post by dubiousgolfer on Jan 23, 2018 6:14:32 GMT -5
Dr Mann - To be honest 'No'. I tried to get into that P4 position and found it almost impossible to push up with the trail hand (in the suggested video's direction), and it's more difficult trying to replicate the same UP force with a lead arm swing only. That's why I found it so confusing , because the physics does seem to make sense but the feasibility of doing this with the human body doesn't.
Anyhow , many thanks for the reply.
Regards DB
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Post by imperfectgolfer on Jan 25, 2018 11:33:26 GMT -5
Dr Mann - To be honest 'No'. I tried to get into that P4 position and found it almost impossible to push up with the trail hand (in the suggested video's direction), and it's more difficult trying to replicate the same UP force with a lead arm swing only. That's why I found it so confusing , because the physics does seem to make sense but the feasibility of doing this with the human body doesn't. Anyhow , many thanks for the reply. Regards DB I think that there is a very simple reason why the clubhead moves upwards at the start of the downswing. Let's presume that your left arm is at 10;30 o'clock at the P4 position and that you have a lag angle of 90 degrees. That means that your on-plane clubshaft should be pointing left of the target and it should be angled upwards (as viewed from face-on). Then presume that you start the downswing by moving your left arm to the 10 o'clock position while maintaining a lag angle of 90 degrees. Wouldn't the clubhead automatically/naturally move upwards (skywards) simply because the clubshaft angle would become steeper? Here are capture images of Jason Day. Image 1 is at his P4 position. Image 2 is at the start of his downswing when he moves his left arm downwards from the 10:30 o'clock position to the 10 o'clock position while maintaining the same degree of lag. Note that his clubhead moves upwards. Who cares what theoretical forces are in play during this time period - considering the fact that the golfer only has to think of moving his left arm downwards-outwards-slightly backwards (away from the target) as he rotates his upper torso counterclockwise prior to the release of PA#4, while maintaining the same degree of lag. Jeff.
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Post by dubiousgolfer on Jan 29, 2018 7:39:16 GMT -5
Yes , I think Sasho's video can be useful (for those interested in the Kinetics of the golf swing) for describing which forces are being used to assist in "maintaining the same degree of lag" from P4 -P5. I obviously can't be certain but it almost seems as if there is a bit of 'PA5' (ie. your new accumulator concept) involved during P4-P5 with a torque being produced from the right shoulder (secondary to an active pivot) that helps create a greater right hand force on the grip (relative to the left hand) and also creates that 'lagging moment of force' (ie. negative torque) on the club. In fact , I've always wondered if the 'torques' (generated by the pivot) at the left and right shoulder sockets are equal in size and move with the same angular velocity (relative to the upper pivot centre) from P4-P5. PS. I've probably not explained clearly why that right hand force would be greater than left hand for 'maybe' an equal torque at the shoulders but it was explained in Tutelman's article below: www.tutelman.com/golf/swing/leecommotion1.php
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Post by imperfectgolfer on Jan 29, 2018 9:48:42 GMT -5
Yes , I think Sasho's video can be useful (for those interested in the Kinetics of the golf swing) for describing which forces are being used to assist in "maintaining the same degree of lag" from P4 -P5. I obviously can't be certain but it almost seems as if there is a bit of 'PA5' (ie. your new accumulator concept) involved during P4-P5 with a torque being produced from the right shoulder (secondary to an active pivot) that helps create a greater right hand force on the grip (relative to the left hand) and also creates that 'lagging moment of force' (ie. negative torque) on the club. In fact , I've always wondered if the 'torques' (generated by the pivot) at the left and right shoulder sockets are equal in size and move with the same angular velocity (relative to the upper pivot centre) from P4-P5. PS. I've probably not explained clearly why that right hand force would be greater than left hand for 'maybe' an equal torque at the shoulders but it was explained in Tutelman's article below: www.tutelman.com/golf/swing/leecommotion1.phpIt is certainly possible that an active pivot action can provide swing power during the P4 => P5 time period for the eventual release of PA#4 via two mechanisms - i) the left shoulder socket pulling the left arm targetwards and ii) the bent right arm applying push-pressure at P#1 via the right palm during an active right arm adduction maneuver. It would be very fruitful with respect to our better understanding of golf swing biomechanics/mechanics if some golf researcher did a pressure sensor study where a pressure sensor placed at PP#1 could detect the amount of push-pressure being exerted by the right palm against PP#1 at every moment during the downswing. An active right arm adduction maneuver between P4 and P5.5 combined with a bent right wrist and supinated right forearm can also potentially allow a golfer to maintain a lot of lag - as seen in Jamie Sadlowski's golf swing. Note how JS maintains a lot of lag at P5 (image 5) - and an active right arm adduction maneuver combined with a bent-back right wrist and a supinated right forearm may make this more easily achievable. He could also be applying push-pressure against PP#1 between P4 and P5 with his right palm thereby allowing his upper torso rotation to be applying pivot power to his left hand via right palm push-pressure against PP#1 - note how he first starts to release PA#4 between image 4 and image 5. Jeff.
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