|
Post by dubiousgolfer on Jun 19, 2019 19:51:16 GMT -5
I've tried to create force diagrams on the double-pendulum model for Pure swinging, Swing-Hitting , Pure Hitting. Don't know whether they are correct or not but made an effort to try and understand how 'Moments of Force' could influence the golf swing. ------------------------------------------------------------------------ ----------------------------------------------------------------------------------- ---------------------------------------------------------------------------- ------------------------------------------------------------------------------
|
|
|
Post by imperfectgolfer on Jun 20, 2019 9:10:53 GMT -5
I've revisited the diagrams above and made it slightly more reflective of an actual swing (using a pivot torque rather than weight). It still shows a force F1 that will cause m1 (distal mass point) to rotate and align itself with F1. If I've got the physics correct and it reflects what actually happens in a golf swing ,then to stop that clockwise rotation one would need apply a bracing positive torque/couple via the hands (or let the club rotate clockwise until one reached the limit of left wrist radial deviation - which will then become that bracing torque). I've emailed Dave Tutelman about the above (no reply yet) but I've also asked a physics professor (awaiting reply). I don't think Dave Tutelman will reply back to me as he regards TGM (and people who still believe in its concepts) as outdated , unfairly imho. I'm sure he would have changed his thinking if he spent some time reading through your articles in more detail. I think my confusion is the PP1 pressure force. Isn't it also likely that applying that force on the aft side of the grip may also cause the last 3 fingers of the right hand to also push on the forward side of the grip? This would cause an active right wrist torque (a couple) but this could not be applied if forward shaft bend was happening (as Tutelman has shown using ShaftLab research data for pro swings of 5 iron- Driver). But active right wrist torque might be useful for short irons , and speciality shots out of rough. So I'm wondering whether 'hitting' is actually 'active right wrist torque' happening in the golf swing when using a dominant PA1# release (with PP1 and PP3 linear pressure forces being applied but also pressure forces being applied on the grip by the last 3 fingers of the right hand). DG I don't understand your questions. I don't understand what you mean by stating that "pressure is being exerted by the last 3 fingers of the right hand". I also don't know what you mean by "active right wrist torque". Does it mean "something" different than applying push-pressure against PP#1 and PP#3 with the right hand? Jeff.
|
|
|
Post by dubiousgolfer on Jun 20, 2019 19:42:23 GMT -5
I've revisited the diagrams above and made it slightly more reflective of an actual swing (using a pivot torque rather than weight). It still shows a force F1 that will cause m1 (distal mass point) to rotate and align itself with F1. If I've got the physics correct and it reflects what actually happens in a golf swing ,then to stop that clockwise rotation one would need apply a bracing positive torque/couple via the hands (or let the club rotate clockwise until one reached the limit of left wrist radial deviation - which will then become that bracing torque). I've emailed Dave Tutelman about the above (no reply yet) but I've also asked a physics professor (awaiting reply). I don't think Dave Tutelman will reply back to me as he regards TGM (and people who still believe in its concepts) as outdated , unfairly imho. I'm sure he would have changed his thinking if he spent some time reading through your articles in more detail. I think my confusion is the PP1 pressure force. Isn't it also likely that applying that force on the aft side of the grip may also cause the last 3 fingers of the right hand to also push on the forward side of the grip? This would cause an active right wrist torque (a couple) but this could not be applied if forward shaft bend was happening (as Tutelman has shown using ShaftLab research data for pro swings of 5 iron- Driver). But active right wrist torque might be useful for short irons , and speciality shots out of rough. So I'm wondering whether 'hitting' is actually 'active right wrist torque' happening in the golf swing when using a dominant PA1# release (with PP1 and PP3 linear pressure forces being applied but also pressure forces being applied on the grip by the last 3 fingers of the right hand). DG I don't understand your questions. I don't understand what you mean by stating that "pressure is being exerted by the last 3 fingers of the right hand". I also don't know what you mean by "active right wrist torque". Does it mean "something" different than applying push-pressure against PP#1 and PP#3 with the right hand? Jeff. Dr Mann Basically , I cannot understand the physics that can explain: 1. How a 'hitting' action can be achieved just using PP1 and PP3 pressure forces. 2. How an overly dominant PP1 and PP3 can cause a flipping action The term 'active wrist torque' was from Tutelmans website (described below). "The picture shows what we really mean by wrist torque, when we use the double pendulum model. It is not a force that tries to twist the shaft about its axis, but rather a force from the hands that tries to turn the club down to the ball -- a force that releases the wrist cock."
I suspect he is inferring the use of forearm muscles to actively release PA2# --------------------------------------------------------------- Releasing PA2# using left forearm muscles If one looks at the left hand , I suspect one could use the 'extensor carpi ulnaris muscle' in the forearm' to create ulnar deviation. Wouldn't this cause a pressure force on the shaft by the thumb and another opposite force by the last 3/4 fingers (as shown in image below) to create a 'torque' which will release PA2#? ------------------------------------------------------- -------------------------------------------------------------------- Right Forearm Supination Trying to describe an active wrist torque by the right forearm supination is a bit tricky. If a golfers right hand is supporting the intact LFFW on plane in the downswing, and uses a pitch elbow action, I am assuming this will cause the right forearm to supinate. If that supination is overly active it can cause a wrist torque that can also release PA2# (see image below). ------------------------------------------------- ----------------------------------------------------- If the physics is right , overly dominant use of linear pressure forces like PP1 and PP3 might not cause premature release of PA2# or a flipping action. It looks like one might need to use active wrist torque as described above. All this is just hypothetical on my part until I can ask someone qualified to check whether my physics is correct. DG
|
|
|
Post by imperfectgolfer on Jun 20, 2019 21:30:55 GMT -5
I've tried to create force diagrams on the double-pendulum model for Pure swinging, Swing-Hitting , Pure Hitting. Don't know whether they are correct or not but made an effort to try and understand how 'Moments of Force' could influence the golf swing. ------------------------------------------------------------------------ ----------------------------------------------------------------------------------- ---------------------------------------------------------------------------- ------------------------------------------------------------------------------ You wrote-: " Basically , I cannot understand the physics that can explain: 1. How a 'hitting' action can be achieved just using PP1 and PP3 pressure forces. 2. How an overly dominant PP1 and PP3 can cause a flipping action". I think that a TGM hitting action that releases PA#2 can occur secondary to the release of PA#1 (right arm straightening action combined with a "fixed" right wrist extension phenomenon) that causes the right hand to apply push-pressure at both PP#1 and PP#3 in the direction of left wrist radial => ulnar deviation. I don't believe that isolated push-pressure by the right hand at PP#1 will produce flipping because the push-pressure is being applied above the coupling point. I believe that flipping will more likely happen if the push-pressure being applied by the right hand is only applied below the coupling point at PP#3 - eg. due to a right wrist straightening action (which should not happen in a TGM hitting action because the right wrist is kept "fixedly" bent throughout the downswing and early followthrough). You wrote-: "If one looks at the left hand , I suspect one could use the 'extensor carpi ulnaris muscle' in the forearm' to create ulnar deviation. Wouldn't this cause a pressure force on the shaft by the thumb and another opposite force by the last 3/4 fingers (as shown in image below) to create a 'torque' which will release PA2#?"
I can imagine that one can manually produce a PA#2 releasing force by manually inducing ulnar deviation by muscularly contracting the left extensor capi ulnaris muscle, but use of that manual "force" is not recommended in either a TGM swinging technique. or a TGM hitting technique. Also, that muscular-induced "force" would be insignificantly small and of little relevance.
I cannot understand your claims in this annotated image. I have no idea why you believe that an overactive right forearm supination phenomenon will induce the release of PA#2 (which is due to left wrist ulnar deviation). Right forearm supination may produce increased pressure in the right hand's 2nd, 3rd, 4th and 5th fingers in the clockwise direction of increased clubshaft shallowing, but any resultant "force" produced will be be at right angles to the plane of left wrist radial => ulnar deviation. I cannot understand why you believe that it will produce a "force" in the plane of release of PA#2 (plane of left wrist radial => ulnar deviation). Jeff.
|
|
|
Post by dubiousgolfer on Jun 21, 2019 8:32:35 GMT -5
Dr Mann
"have no idea why you believe that an overactive right forearm supination phenomenon will induce the release of PA#2"
I made a video that makes me believe this (see below). I attached pens to represent the forces via the thumb and last 3/4 fingers of the right hand and just made a pitch elbow move.
As you can see , the pens rotate in space as if there is a torque/couple created by the net supination of my right forearm as I do the pitch elbow move. Won't that torque help release PA2# while in plane?
DG
|
|
|
Post by imperfectgolfer on Jun 21, 2019 9:07:37 GMT -5
Dr Mann "have no idea why you believe that an overactive right forearm supination phenomenon will induce the release of PA#2"I made a video that makes me believe this (see below). I attached pens to represent the forces via the thumb and last 3/4 fingers of the right hand and just made a pitch elbow move. As you can see , the pens rotate in space as if there is a torque/couple created by the net supination of my right forearm as I do the pitch elbow move. Won't that torque help release PA2# while in plane? DG Nice video! I agree that you are creating a torque, but I think that it is across the plane of the intact LAFW and it causes the shaft to shallow. If your left arm/hand was attached to that shaft, then the left forearm would have to pronate more to allow that clubshaft shallowing phenomenon (secondary to increased right forearm supination) to happen. Shallowing the shaft between P4 and P6 changes the plane of the intact LAFW, but it does not induce a PA#2 releasing action, which must happen within the plane of the intact LAFW (within the plane of left wrist radial => ulnar deviation). Jeff.
|
|
|
Post by dubiousgolfer on Jun 22, 2019 9:38:13 GMT -5
Dr Mann
On reflection , it does look like my 'overactive right forearm supination phenomenon to induce the release of PA#2' is indeed flawed thinking. I need to revisit this again.
Could the torque have been created by the straightening of my right wrist in the plane of the 'Right Arm Flying Wedge'? Could I cause a PA2# release my actively flexing my right wrist (providing I used a neutral grip)?
Can how I grip the club with the right hand also dictate how I could release PA2# and still keep an intact LFFW? For example, couldn't I deploy a very strong right hand grip and use radial- ulnar deviation of both left and right wrists together to release PA2#?
Apologies - I've striked through the above (irrelevant questions).
DG
|
|
|
Post by dubiousgolfer on Jun 23, 2019 11:52:43 GMT -5
Dr Mann "I don't believe that isolated push-pressure by the right hand at PP#1 will produce flipping because the push-pressure is being applied above the coupling point. I believe that flipping will more likely happen if the push-pressure being applied by the right hand is only applied below the coupling point at PP#3 - eg. due to a right wrist straightening action (which should not happen in a TGM hitting action because the right wrist is kept "fixedly" bent throughout the downswing and early followthrough)."
Can you advise if you have any detailed information about this 'coupling point' and any evidence that shows push pressure PP#1 below 'coupling point' might cause flipping? I've searched the internet for 'coupling point' and all it seems to be is a reference point to define the hub path but no info about how forces applied above or below this point affects the movement of the club. I've seen a research article that describes the pivot point in the golf swing being way above this coupling point (see below). So if the below is correct why should a PP#1 force above the coupling point be any different to one below? If the above pivot points were fixed stationary in space and then a right hand applied a PP#1 force vector : 1. A PP#1 force vector pointing through the pivot points would not cause the club to rotate. 2. If the PP#1 force vector pointed below the pivot points , then I could readily imagine that it would cause the club to rotate But what if the club were regarded as a free moving body in space and then a PP#1 force was applied 'not in line' with its COG ? It would cause a rotation as shown in Sasho's video below (look at the CD player floating in space example and what happens if a force is applied not through its COG). The issue I do not understand is whether to regard those pivots in the first diagram (on the left arm) as being relatively fixed in space compared to the golf club. If it were then any PP#1 force below those pivot points would cause a club rotation. But if the left arm and club are regarded as free moving bodies in space (as if floating in space) , then a PP#1 force not through the clubs COG will cause a rotation (where the clubs COG will rotate and align with the tail of that vector force). Difficult one for me to understand and which is why I need someone who is an expert in physics/mechanics for assistance. DG ADDENDUM: I've also found this old Brian Manzella video mentioning coupling point but when he demonstrates a 'Force across the shaft' through the coupling point , he has firmed up the wrists/forearms . He has therefore created a rigid body unit of 'left arm and club' combined and the pivot point will become his lead shoulder (which can be relatively stationary from a lateral perspective in the late downswing). A force across the shaft in that scenario (where he uses his right finger) will obviously not cause any flipping but push the left 'hand/club/arm' unit forward in an arc (like a simple rigid pendulum arm where the pivot is the left shoulder joint). The same movement of hands 'forward in an arc' would apply if he firmed his 'wrists/forearms' as before but applied that 'force across the shaft' below the coupling point. This coupling point makes no sense to me from a physics standpoint because its not a real pivot point , just a useful reference point that BM used to explain his 'Alpha Torque' concept (showing a 'couple' made by the wrists/hands whose centre is something he coins the 'coupling point').
|
|
|
Post by dubiousgolfer on Jul 16, 2019 5:17:59 GMT -5
I have now received a reply from Dave Tutelman regarding my diagrams below: Dave Tutelman- email response: Your diagram with a vertical and horizontal force is almost perfect. I only say "almost" because, while the left arm pull and the right hand push are probably close to vertical and horizontal, respectively, there's no reason to suspect it is exact -- nor even approximate enough to tell us something important.You really want the resultant force of both hands on the handle. If its component along the arc of the hands is "back", then it produces a positive moment of force about the center of mass. And the relative sizes of the forces you show are misleading. The left arm pull has to exert something like 100 pounds of centripetal force to keep the club in the hands, so it is going to be a lot larger than the roughly tangential force of the right hand.BTW, the biomechanical models I have seen designate the forces to be applied at the mid-hands point, not the left wrist. I understand why you think about it that way, and I did for years. It may make some sense for intuition. But as soon as you try to analyze what the forces do to the club, you want a free-body diagram of the club with the forces related to the center of mass -- not some "fulcrum" that it's nice to think about. The intuition of the fulcrum is often misleading. The fulcrum will exert its own force, as needed to keep the analysis consistent.Thinking about the hands as a clamp is a trap for the informal analyst. It is nothing like fixed. (And, of course, the wrist is one step removed from this, but the principle is still the same.) The hand and arm have a mass and have the proximal members exerting forces on them, to be sure. But those forces and masses are hardly enough to keep the hands fixed in any way that is meaningful to the analysis.So I think Dave Tutelman is in agreement with me about the physics of the force vectors across the shaft. But to all intents and purposes, that vertical pull via the lead arm is so large that it makes the tangential force element almost unimportant (from a clubhead speed perspective) for a TGM swinger with a pivot release of PA4#.
For a hitter , imho , just using a 'push force' across the shaft (like F2 in the first diagram or F1 in the 2nd diagram) will cause a lagging moment of force , so doesn't that mean a requirement to add positive torque with the right hand to counteract that 'lagging moment of force'? That to create clubhead speed , one must not also push with the right hand to create tangential hand speed (and therefore increased linear speed of the clubs COM), but it must also be accompanied with right hand positive torque (in the absence of a left arm pulling force across the shaft).DG
|
|
|
Post by dubiousgolfer on Jul 28, 2019 12:06:38 GMT -5
Just looking at this video by Mike Jacobs and noticed that it correlates with what I've said above. But imho, it proves that he is advocating a 'hitting' action (as I've inferred above) using an active couple with both left and right hands around the 'coupling' point (ie. Alpha Torque) while also applying PP1 and PP3 linear forces.
Imho , he and Brian Manzella (for some unknown reason) have ignored the pull force (across the shaft and in front of the clubs COM) via the lead arm using an active pivot (ie. a TGM 'swinging' action).
Why won't Nesbitt point this out as I'm sure he is aware that both Jacobs and Manzella are showing an incomplete picture of the physics involved in a golf swing?
DG
|
|
|
Post by imperfectgolfer on Jul 28, 2019 17:27:38 GMT -5
Just looking at this video by Mike Jacobs and noticed that it correlates with what I've said above. But imho, it proves that he is advocating a 'hitting' action (as I've inferred above) using an active couple with both left and right hands around the 'coupling' point (ie. Alpha Torque) while also applying PP1 and PP3 linear forces. Imho , he and Brian Manzella (for some unknown reason) have ignored the pull force (across the shaft and in front of the clubs COM) via the lead arm using an active pivot (ie. a TGM 'swinging' action). Why won't Nesbitt point this out as I'm sure he is aware that both Jacobs and Manzella are showing an incomplete picture of the physics involved in a golf swing? DG I personally think that Michael's video is insanely wrongheaded! Also, note that I have resisted responding to some of your other opinions expressed in recent posts in this thread because they make no sense to me. I am not claiming that your (and DT's) opinions are wrong, but I personally find them to be incomprehensible. Jeff.
|
|