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Post by dubiousgolfer on Jun 14, 2020 9:36:17 GMT -5
Example 1 Endless Belt (how a tighter circular hand path will increase clubhead speed). The maths is correct but one can quite easily show pictorially how the MOF could be applied to the endless belt concept by changing the club to a more lagging position before the pulley starts rotating the club (I'll add an image a littler later). k = 1 + L/R
Therefore a sudden decrease in R (hand path radius ) will cause an increase k which means V2 /V1 will increase
DG
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Post by dubiousgolfer on Jun 14, 2020 10:10:39 GMT -5
Example 2 (Endless Belt with club lag) - Shows how a tangential (FT) and radial force (FR) added together can create a 'Net Force' that will be angled in a direction in front of the COM of the clubhead (M1). This will cause an MOF release of PA#2. DG
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Post by dubiousgolfer on Jun 15, 2020 9:18:59 GMT -5
Hi Dr. Mann, Note how I used the term wristcock angle and not left hand wristcock angle (left hand radial deviation). I believe that the characteristic of release involves the clubhead's position "behind" the right hand. The most influential "reduction in radius" is at the bottom, at the release point where, with the grip positioned along the roots of the fingers of the right hand, the release radius is smallest as the right hand begins to exhibit palmar flexion. Call the release, if you will, a release from the "right hand cocked position." Where there is nowhere else to look to explain clubhead speed difference among players, I believe that the difference lies in the "radius of release" both in terms of linear distance of hand travel during release as well as the release of the club "around" the right hand. S Hi S I think there is definitely a connection with increased clubhead speed and a tighter circular hand path during release (apart from the hand/club speed generated from P4 to around P5.5). I cannot see how the 'release radius' by the right hand from dorsi- palmar flexion could be any different from the radial -ulnar deviation of the left hand . For your theoretical concept to be feasible , you will somehow need to suddenly stop the right wrist joint in space to change the clubs COM from moving in a larger radius of curvature to a minimal radius of curvature (with the right wrist joint almost stationary in space). How could one do that 'move' in some anatomically natural way? I can understand how one could maybe restrict the movement of the pitch elbow position over the right hip and abruptly decrease the effective radius of the right hand path and also the 'clubs COM' curvilinear path. To do the latter would also mean changing the hand path of the left arm at the same time by some biomechanical means maybe by : 1. Bent left arm? 2. Steeper movement of left shoulder socket up and back during release? Whatever the biomechanics , the 'decreasing of the hand path radius of curvature ' needs a force applied to them and therefore across the 'Mid-Hands' point on the grip (ie. the Net Force) to create an MOF that will increase the angular velocity of the club. Imho, the decrease in hand path radius of curvature and the generation of the 'Net Force' to cause that MOF go 'hand in hand'. DG PS. Can one now see that the 'release' of PA#2 is virtually the same physics involved in 'parametric acceleration' ? I say virtually the same because in parametric acceleration , there is a negative hand couple accompanying the MOF whereas during PA#2 release there seems to be some small 'positive hand couple' .
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Post by imperfectgolfer on Jun 15, 2020 10:07:50 GMT -5
DG, I don't dispute the validity of the endless belt model where the power of the PA#2 release phenomenon will be much greater when the club moves around the pulley's more "tightly" circular hand arc path. However, such a dramatically "tight" circular hand arc path is not seen in the "real life" golf swings of pro golfers. Here is Jamie Sadlowski's hand arc path.
His hand arc path is very "straightish" between point 1 and point 2, and it becomes much more circular between point 2 and point 3 and yet there is very little club release happening between point 2 and point 3. JS's club release action mainly happens after point 3 when the hand arc path is becoming less "tightly" circular.
I have seen this same phenomenon in many other pro golfers where the club release action happens much closer to P5.5 even though the hand arc path's maximum degree of circularity happens between P5 => P5.3.
More importantly, are the calculated MoF values for "real life" pro golfers.
The MofF values become positive after P5.5, but their magnitude is not large enough between P5.5 => P6 to be solely responsible for causing the PA#2 release phenomenon. I believe that the hand couple torque being positive up to P5.5 provides an additional amount of PA#2 releasing power that adds to the PA#2 releasing power due to an increasing MofF. One can think of the hand couple torque as providing an extra "kick" to the club releasing phenomenon that happens at about P5.5.
The problem with TGM's rigid model of dividing golfers into swingers and hitters is that it implies that a TGM swinger gets all his swing power (PA#4 => PA#2) from the lead arm and it does not take into account the possibility that the trailing arm can assist in the release of PA#4 and PA#2. I am now increasingly sympathetic to the "idea" that the trailing arm can assist in the release of both PA#4 and PA#2.
I also think that the TGM concept of a TGM hitting technique as being a viable technique for a full golf swing action is invalid. The "axe handle" technique where a trailing arm provides a positive torque against the aft side of the club all the way into impact does not apply to a full golf swing action, and it only applies to a punch shot from a shortened backswing position.
The TGM instructor who is most famous for teaching a TGM hitting technique was Ted Fort.
Here is Ted Fort demonstrating a TGM hitting swing action.
Note that the peripheral clubshaft is bent forward at P6.3 (image 4) which is incompatible with a positive torque being applied in the late downswing.
Note that he is using a pitch elbow motion of his right arm, which limits the amount of positive torque that can practically be applied to the aft side of the club handle - even if the release of PA#1 is active - and that can help explain why the "real life" torque in the later downswing is actually negative.
I now believe that the active release of PA#1 (prescribed for a TGM hitting technique) is simply a manifestation of a golfer increasing the positive "force-across-the-shaft" in a slightly different manner to a TGM swinger, who is unknowingly applying a small amount of positive hand couple torque between P4 and P5.5. In fact, if you think about it more carefully, the TGM concept of "extensor action" (which is recommended by Homer Kelley) is equivalent to the trailing arm applying a small level of positive "force-across-the-shaft" in the same manner as would happen in a hand couple phenomenon. However, it is practically not possible to keep-on applying a positive"extensor action" force after P5.5 when the club releases very fast because the right hand cannot easily keep up with the releasing club.
Jeff.
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Post by dubiousgolfer on Jun 15, 2020 10:33:35 GMT -5
Dr Mann
"The MofF values become positive after P5.5, but their magnitude is not large enough between P5.5 => P6 to be solely responsible for causing the PA#2 release phenomenon. I believe that the hand couple torque being positive up to P5.5 provides an additional amount of PA#2 releasing power that adds to the PA#2 releasing power due to an increasing MofF. One can think of the hand couple torque as providing an extra "kick" to the club releasing phenomenon that happens at about P5.5."
It looks like you are correct .
PS. Still wondering why Dr Kwon has normalised his graphs with the mass of the golfer. I can only assume he thinks there is some direct relationship between the mass and strength of the golfer and his/her ability to create that MH-Net force (and therefore MOF).
DG
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Post by imperfectgolfer on Jun 15, 2020 11:41:55 GMT -5
Here is a question for golfers who like to think deeply about golf swing biomechanics. Here is the result of a study using the Koike instrumented grip on a single pro golfer.
Note that the trailing arm is applying a positive "force-across-the-shaft" between P4 and P5.5, while simultaneously applying a negative "force-along-the-shaft" (that pulls the grip onto the shaft). How is that combination biomechanically possible? Jeff.
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Post by dubiousgolfer on Jun 15, 2020 11:52:04 GMT -5
Dr Mann
I can only assume that the left arm is pulling while the right arm is impeding (ie. not moving as quickly) . We therefore have a 'tug of war' happening between the hands on the grip while both are still moving along the hand path.
Could that explain why we have an increasing tangential hand force from P6-P7 while the left hand speed is decreasing?
DG
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Post by imperfectgolfer on Jun 15, 2020 11:59:45 GMT -5
Dr Mann I can only assume that the left arm is pulling while the right arm is impeding (ie. not moving as quickly) . We therefore have a 'tug of war' happening between the hands on the grip while both are still moving along the hand path. Could that explain why we have an increasing tangential hand force from P6-P7 while the left hand speed is decreasing? DG DG, Why would the right arm be impeding the motion of the club handle down the hand arc path between P4 and P5.5 if the right upper arm is being actively adducted in an unimpeded manner during that same time period? Jeff. p.s. According to this Dr. Kwon graph, the tangential force peaks at P6, and then decreases between P6 => P7.
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Post by dubiousgolfer on Jun 15, 2020 13:34:27 GMT -5
Dr Mann
I think that tangential force is increasing from P6-P7 because the clubshaft is becoming progressively aligned with the left arm . The left arm has to exert more 'pull force' (increased tension in the left arm) to counteract the 'inertial' pull of the club which increases progressively from P6 - P7 to about 100 lbs weight force. The component of that pull force along the shafts axis explains the increasing tangential force while the angular velocity of the arm/hand decreases.
DG
PS. Got this completely wrong - sorry.
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Post by imperfectgolfer on Jun 15, 2020 13:40:02 GMT -5
Dr Mann I think that tangential force is increasing from P6-P7 because the clubshaft is becoming progressively aligned with the left arm . The left arm has to exert more 'pull force' (increased tension in the left arm) to counteract the 'inertial' pull of the club which increases progressively from P6 - P7 to about 100 lbs weight force. The component of that pull force along the shafts axis explains the increasing tangential force while the angular velocity of the arm/hand decreases. DG See the graph in my previous post. The tangential force decreases between P6 => P7. The radial force increases between P6 => P7 and that will counteract the outwards-directed 100lbs force that happens at impact. Jeff. p.s. This is a separate (tangential) issue that has nothing to with my question about the trailing arm.
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Post by dubiousgolfer on Jun 15, 2020 17:53:04 GMT -5
Dr Mann Apologies but I am getting confused with the Dr Kwon graphs that we should agree reflect the MH Tangential and Radial forces . Is it these ones below or the Fig 3 graph above? With regard the Koike graphs , I'd rather use his repeat experiment in 2016 (diagrams below). For graph 'a' the results were virtually the same as the one in 2006 and Tutelman states (on his website) the following: ""Graph (a) shows the force across the shaft by each hand individually, the pull by the left hand and push by the right hand. (Actually, it's measured as a push either way; the mostly negative dotted curve says the left hand force is a pull until almost impact.) They are nearly equal the whole duration of the downswing, and comprise a couple almost perfectly. The forces cross about 20% of the downswing time before impact, and form a negative couple of about 10 Nm at impact."So yes , the right hand is applying a push force in the early downswing and almost to impact but check out graph 'c' which shows that its 'couple' is closer to zero and becomes more negative by P5 ,becoming zero by P5.3 , positive from P5.3- P6.5 , then drops quickly to near zero by P7. The left hand is pulling from P4 almost to P7 and is exerting a virtually constant positive couple from P4-P5 , then it drops progressively to zero by P6.5 , becomes more negative all the way to P7 (although a slight blip where it becomes slightly less negative just before impact). Now look at graph (b) for forces along the shaft (y axis) which is very different from the 2006 graph (b). Check the right hand graph which (imho) shows a fairly constant drag impedance force from P4-P7 as if its just holding onto the club and not applying any active right arm adduction ( ie. a passive right arm straightening action). The left hand/arm is responsible for virtually all the force down the shaft from P4-P7. It's very difficult to make any 'generic' sense of the golf swing biomechanics using the sample graphs of single golfers that Koike used in his research. I don't even know whether he used the same golfer in both experiments but the 'forces along the shaft ' graphs for 2006 and 2016 look completely different. DG PS. I struck through 'passive right arm straightening action' because the right hand is applying positive torque from P5.3-P7 and that may actually be caused by a right arm straightening action (don't know for certain).
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Post by dubiousgolfer on Jun 15, 2020 18:24:55 GMT -5
I checked with Dr Kwon about those graphs and Dr Mann is correct.
Dr Kwon says:
"It is force normalized to body mass to eliminate the effect of body size."
I find this completely and utterly confusing.
DG
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Post by dubiousgolfer on Jun 15, 2020 18:49:50 GMT -5
Dr Mann
Aren't we forgetting PING MAN and IRON BYRON? They swing without the use of any positive hand couple torque.
If it is found that real life Tour Pro golfers might be using some positive torque to 'kick start' the release of PA#2 , that still doesn't mean they are using optimal biomechanics.
DG
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Post by imperfectgolfer on Jun 15, 2020 19:18:17 GMT -5
Dr Mann Apologies but I am getting confused with the Dr Kwon graphs that we should agree reflect the MH Tangential and Radial forces . Is it these ones below or the Fig 3 graph above? With regard the Koike graphs , I'd rather use his repeat experiment in 2016 (diagrams below). For graph 'a' the results were virtually the same as the one in 2006 and Tutelman states (on his website) the following: ""Graph (a) shows the force across the shaft by each hand individually, the pull by the left hand and push by the right hand. (Actually, it's measured as a push either way; the mostly negative dotted curve says the left hand force is a pull until almost impact.) They are nearly equal the whole duration of the downswing, and comprise a couple almost perfectly. The forces cross about 20% of the downswing time before impact, and form a negative couple of about 10 Nm at impact."So yes , the right hand is applying a push force in the early downswing and almost to impact but check out graph 'c' which shows that its 'couple' is closer to zero and becomes more negative by P5 ,becoming zero by P5.3 , positive from P5.3- P6.5 , then drops quickly to near zero by P7. The left hand is pulling from P4 almost to P7 and is exerting a virtually constant positive couple from P4-P5 , then it drops progressively to zero by P6.5 , becomes more negative all the way to P7 (although a slight blip where it becomes slightly less negative just before impact). Now look at graph (b) for forces along the shaft (y axis) which is very different from the 2006 graph (b). Check the right hand graph which (imho) shows a fairly constant drag impedance force from P4-P7 as if its just holding onto the club and not applying any active right arm adduction ( ie. a passive right arm straightening action). The left hand/arm is responsible for virtually all the force down the shaft from P4-P7. It's very difficult to make any 'generic' sense of the golf swing biomechanics using the sample graphs of single golfers that Koike used in his research. I don't even know whether he used the same golfer in both experiments but the 'forces along the shaft ' graphs for 2006 and 2016 look completely different. DG PS. I struck through 'passive right arm straightening action' because the right hand is applying positive torque from P5.3-P7 and that may actually be caused by a right arm straightening action (don't know for certain). DG, I agree with you - it is very confusing when they show graphs that have different results. So, Dr. Kwon's tangential force graph (that you have posted here) shows that it increases all the way into impact, while that other posted graph shows the tangential force peaking pre-impact and then decreasing. Likewise, it is also confusing when the Koike graph (you posted) shows that the right hand has produced near-zero force along the Y axis and that all the "force-along-the-shaft" is due to the left hand, which is very different to that Koike graph I posted that was measured on a single golfer. I agree that it is very confusing as to why Dr. Kwon needs to consider body mass in his calculations of forces being exerted at the level of the club handle. Jeff.
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Post by imperfectgolfer on Jun 15, 2020 19:25:52 GMT -5
Dr Mann Aren't we forgetting PING MAN and IRON BYRON? They swing without the use of any positive hand couple torque. If it is found that real life Tour Pro golfers might be using some positive torque to 'kick start' the release of PA#2 , that still doesn't mean they are using optimal biomechanics. DG I have a new "idea" that wonders whether the Pingman machine does not need the addition of a hand couple torque because the hinge joint is free of tension, while human golfers need a hand couple torque to overcome the tension in their wrists that holds back the release of PA#2 and thereby make the left wrist more biomechanically able to uncock freely and without tension (like a Golf Robot machine's hinge joint). Bob Grober has apparently written about this topic and he stated that he will publish his 38-page paper next week. I will let you know when it becomes publically available. Jeff.
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