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  1. Hi Richard - sorry for the delay in replying as I've been busy with other issues for many months . I'm glad that I have provided some information that has been useful to you. Regards Wildthing
  2. There aren't too many PGA tour players who bend their wrists like DJ and Rahm at the top of the backswing . There is a golf instructor called Jon Sinclair who has the worlds largest database of PGA tour player 3D data (literally hundreds of players ). He says that the majority of tour players have an extended or flat lead wrist at the top of the backswing and players like DJ and Rahm are 'outliers' . If you are getting pain in your lead wrist , then maybe its an unnatural movement that you are forcing your wrist to do.
  3. Given up buying and reading golf books (whose instruction never fully worked) but I am busily helping Dr Jeff Mann in spotting errors in his newly edited, free, enormously detailed explanation on the biomechanics of the downswing ( it's going to take me many days ). Pros - It relates to the technique that most golfing pros do (according to Dr Mann) Cons- Its extremely difficult to master Downswing (perfectgolfswingreview.net)
  4. Maybe it would be a good idea to define what a bowed wrist is first. For example: 1. I could just flex and extend my wrists back and forth like the video below. Arm Muscles: 27 Wrist Flexion and Extension - YouTube 2. I could radial and ulnar deviate my wrists like below Supination vs Pronation, Radial vs Ulnar Deviation of the Hand - YouTube 3. Circumduction movements of the wrists where there is a mix of point 1 and Point 2 happening simultaneously . OrthoIndy Exercises | Supported Wrist Circumduction - YouTube The question we must ask is what net effect does the doing of 1 /2/3 (at different positions in the golf swing) have on the clubface as it approaches impact. As far as I am aware there are different geometrical effects on the closure of the clubface at impact depending on when points 1 ,2, 3 might happen during the swing. There is an article below that goes into great detail but be warned this is incredibly non-intuitive and might make your brain spin but it isn't as 'cut and dry' as one might imagine. What effect does lead wrist bowi (perfectgolfswingreview.net)
  5. If you look at Clay Ballards swing in slo-mo near the end of the video (09:27 -09:33) , it almost seems like he got his right elbow stuck by his torso because he's straightening his right arm and wrist just before impact. I don't think he does the 'Sam Snead Squat' move to any great degree in his own swing and could be right hip spinning in his early downswing (look at 09:43) blocking the movement of his elbow .
  6. Seems like a the video is trying to explain that the golfer requires something called 'lag tension' to get to a good impact position with some forward shaft lean. I don't understand what 'lag tension' actually is apart from maybe the tension one feels in the lead arm when the dynamic weight of the club maxes out just after impact. But personally , I don't think I need a training aid with some visual etched line to provide me a guide on how to feel that position. Actually ,there was quite a debate on another forum regarding lag tension where Bertie Cordle got personally involved to defend his position. Questionable golf science! | Newton Golf Institute (proboards.com) There is also a link to some research that Dr Sasho MacKenzie did relating to the above. Assessment of DST Impact Line Technology Theory 20 sep 19 4 (dstgolf.com) Note: After seeing the video again , I'm unsure whether Bertie's physics is correct about that 1st 'de-stablising torque' . He says "at full extension, when the clubhead is subjected to its maximal rotational torque, and because the clubhead is moving faster than the players hands, the clubface wants to flip over and rotate around the shaft and close very quickly". Then he goes on to say this explains why Dr Phil Cheetham's research found no difference in shot dispersion accuracy between high and low handle twist velocity (what does it explain? Makes little sense to me). Also , where is his evidence regarding the 2nd destabilising torque where he infers that a flipping hand release action will increase the forward shaft bend of the shaft compared to a hand release action where there is forward shaft lean at impact? Why hasn't he mentioned clubhead droop ? Isn't that another golf club torque or it too small to be considered? I'll need to check the above with Dave Tutelman but I suspect the degree of forward bend at impact could be dependent on several factors . The degree of hand couple/torque being applied by the hands on the grip , the timing of its application, clubshaft characteristics (ie. how quickly the shaft tries to restore its shape- its elasticity). I don't think a golfer has enough time to muscularly do things (ie. micro manage destabilising torques) at the grip end for it have much effect at the club end in the late downswing. The physics to close the clubface by impact would have had to be initiated a lot earlier in the downswing. Also at 26:21 -26:46 he mentions 'Gear Effect ' with an image of an iron , but, unless I'm mistaken, there is no only some 'gear effect' with irons (check out link and extract below) but not as much as drivers. Design Notes - Golf Physics p2 (tutelman.com) Gear effect is sidespin which is the result of an off-center hit with a club whose center of gravity is well back from the clubface. Without both these conditions, gear effect does not happen. Here is a very short description of gear effect. If you are interested in more, I have written a very detailed article on it. Let's see what causes gear effect. In the picture at the right, we have two off-center impacts, one on an iron and the other on a driver. Both are toe impacts, which means it is to the toe side of the center of gravity of the clubhead. (The CG is denoted by the four-quadrant black-and-white circle; it's a pretty common notation for CG.) What does Newton say about such an impact? The CG wants to continue moving forward in a straight line, but there is a force on the clubhead that is off that line. That creates a torque that wants to twist the club. The result is that the CG keeps moving forward, but the club rotates around the CG in a clockwise direction (red arrows). The CG of the iron is close to the clubface. So, where the clubface and ball meet, this rotation (the red arrow) consists of the clubface "falling away" from the ball. This results in loss of distance (the momentum transfer is not as complete as it should have been), and perhaps the ball flying somwhat to the right as the face opens. But there isn't any special effect on spin. The driver is a completely different story. Its CG is well behind the clubface. When the driver head rotates around its CG, the whole face of the club moves sideways. Look at the direction of the red arrow where the clubface and ball meet; it is mostly parallel to the clubface, with only a bit of "falling away". So the club's face is moving to the right while the ball is compressed on it. The result is that the ball starts to rotate so its surface doesn't slide along the clubface; remember it's compressed so sliding is difficult. This rotation is the blue arrow in the picture. If the clubhead is rotating clockwise (as in the picture), then the ball rotates counter-clockwise. It's as if the clubhead and ball were a pair of gears, with their teeth meshing where they meet. That's why a toe hit with a driver tends to hook. For all the same reasons, a heel hit with a driver tends to slice. You don't have this effect with an iron. Well, you do, but not nearly as much. The CG of an iron head isn't in the face; it is slightly behind the face. And since this was first written, iron heads are being designed with the CG further and further back, to make them more forgiving and higher launching. So today's irons have more gear effect than 20 years ago, but not nearly as much as drivers.
  7. Although Padraig has tried to explain the hip movement in his own style , there is an alternative theory that could explain the 'what/how' is happening from an anatomical standpoint (but it will take a lot of mental stamina and further investigative work to understand the function of the muscles being discussed). Once you have committed several hours reading through it all in detail you will have (in my opinion) a better appreciation of how the pelvis moves in pro golf swings. http://www.perfectgolfswingreview.net/pelvicrotation.html The above article is complemented in the below video https://youtu.be/gsX-o6ZWeOw PS. There are some TGM references at the start (for 1st 4 mins) regarding power package and intact flying wedges (which you might not agree with from a theoretical perspective) but then he goes into more detail on the pelvic movement.
  8. The graphs above are really describing the movement of the club in space as per diagram below, from top of the backswing P4 to impact P7. They are describing the 'spin' of the club around its COM. So basically the 'Hand Couple' and the 'Moment of Force' (which is also a couple ) has spun the club from P4 to P7 in the time taken to perform the downswing. Using my own driver characteristics : The COM is about 11 inches from the base of the club (ie. length AB =R) = 0.28 Metres Point B will have rotated 270 degrees from P4-P7 = 4.7 radians For a typical pga pro, the downswing time is about 0.25 secs So the average angular velocity (caused by the couples) = 4.7/0.25 = 18.8 rad/sec using V = RW (ie. speed = radius x angular velocity) Average clubhead speed (caused by the couples only) in the downswing= 0.28 x 18.8 = 5.3 metres/sec = 11.9 mph Lets make another large assumption that most of the 'spin' happens around 100 milliseconds from impact (maybe P5.5), so lets use this as the downswing time rather than 0.25 secs The average angular velocity (caused by the couples) = 4.7/0.10 = 47 rad/sec Average clubhead speed in the downswing from P5.5-P7 = 0.28 x 47 = 13.16 metres/sec = 29.4 mph So it's rather amazing that the golfer is actually 'spinning' the clubhead to such a high speed by impact using 'Couples' . The average speed of a PGA golfers driver is 114.1 mph so where is the other 114.1 -29.4 = 84.7 mph coming from ? It has to be coming from linear forces applied via the hands on the clubshaft pulling the clubhead (using increased shaft tension) from P4-P7.
  9. When I look at 'Moment Of Force' graph below (black line) it is therefore representing the 'spin' of the golf club around its COM , not the clubhead (or its COM) rotation around the 'Mid-Hand Point'. Further , 'Hand Couple' (blue graph) is also a 'free vector' and will also cause the club to 'spin' around its COM. What we really need superimposed on the below graphs are 3 more graphs . 1. Speed of clubhead sweetspot vs time 2. Speed of COM of club vs time 3. Net linear force applied by the hand vs time Then we might be able to relate what proportion of 'couple' and 'force' might be contributing to the 'clubhead sweetspot speed' during the downswing .
  10. Is there anyone out there who has a background in physics and maths? I'd like to exchange some private messages with them concerning some issues I don't understand about the golf swing kinetics. Example : I have looked at Dr Sasho MacKenzie's 'Intro To Club Kinetics' VIMEO video below (see up to 06:00 ) and the physics looks wrong. https://vimeo.com/158419250 Sasho says 'Eccentric Linear Net Force' will cause a 'Moment of Force' (ie. Torque) that will rotate the clubs COM (centre of mass) to line up with the net force (see image below). I have plotted the movement of the COM and its a straight line , not rotating at all . Also in physics , an eccentric force (one that doesn't pass through the COM) on a rigid object causes translational movement and a 'couple' . As far as I am aware, a couple will cause rotation of a rigid object around its COM (Centre of Mass) . A 'couple' is a free vector and effectively causes the rigid body to spin around its COM and not cause it to accelerate. The only forces that can rotate the COM of the clubhead is a 'Torque' and that has to be applied via the hands but its NOT that 'Moment of Force'. Other movements by the golfer are somehow being directed through the arms and hands to cause the clubs COM to rotate in the downswing. Unless I'm mistaken, the speed of the clubhead is caused by : 1. Linear forces (mainly via increased tension in the shaft) that will accelerate the COM and clubhead in a straight line . This can be increased by a sudden variation in hand path, with the COM moving in one direction while the hands move in another. 2. 'Intrinsic Spin' of the club around its COM (ie. the 'Couple' caused by the 'Eccentric Net Linear Force' ). This will cause the clubhead to spin around the clubs COM increasing its speed. 3. Torques via the hands (not just active muscular wrist torques although that is a possibility) that move the COM (and therefore clubhead) around in a curvilinear path. All three above are contributing to clubhead speed but its mainly point 1 responsible for clubhead speed in a golfers downswing. Have I made any obvious errors?
  11. For anyone who remembers their old school physics lessons where their teacher used to teach by rote (which my one did and didn't really understand physics at all) this might be confusing. But one can clearly see how easy it is to misinterpret Newton's 2nd Law when applying it to the golf swing. One can end up with a completely wrong perception on how to hit the ball a long distance. https://twitter.com/i/status/1333958039049744387 Dr MacKenzie polled some questions regarding Newtons 2nd Law on his twitter below and there are some surprising results.
  12. Here's some proof that might show there is no motorcycle move and also a bit surprising about the golf swing in general. This is research done by 'Choi' where they've put sensors on the golf grip to measure torques and forces applied via the hands . Look at graphs O and S which show the left and right hand torques applies on the grip (ie. clubshaft twist ). If your into physics you need to use the 'right hand rule ' to visualise the rotation of the club that will produce a torque vector in the 'Z ' axis direction on the coordinate system (connected to the club in that left image). The magnitude is basically zero for the whole downswing and most of the follow-through. Unless I'm mistaken , there doesn't seem to be a 'reverse motorcycle' move being applied via the hands on the grip for the 9 golf pros used . If you look at the shaded areas around the best fit solid line graphs it shows the variance between the golfers data, but its all pretty consistent for graphs O and S (ie . virtually zero torques with no shaded variance regions). This means the clubface squaring is being done by something else and not any torques/twisting on the grip via the hands. Its more likely caused by Dr Sasho Mackenzie's passive torque concept (see image further below) which creates some angular momentum in the yellow arrow direction ,which will increase the angular velocity of the club (around its longitudinal shaft axis) as the left wrist ulnar deviates . For a given initial instantaneous angular momentum, the ulnar deviation causes the MOI of the 'upper arm/forearm/club' unit to rapidly reduce which will cause increasing shaft rotational angular velocity that closes the clubface automatically by impact without any active muscular forearm rotation . PS. The 'Crosswise' force is something else I found out about and too complicated to explain here but it's quite small ( nothing like that Green arrow suggests) and a requirement to facilitate the passive torque effect as seen in the diagram above.
  13. This video is really interesting and way before Tyler Ferrell and Monte Scheinblum started using the 'reverse motorcyle move' , but is it correct ? Have a look at this new article that goes into great depth What effect does lead wrist bowi (perfectgolfswingreview.net) Maybe some of the more technically minded forum members might be able to fit all the pieces of the puzzle together better than I can.
  14. You do understand that Monte Scheinblum is one of Golfwrx sponsors so posting alternative opinions is a banning risk . I don't think Monte himself would demand someone be banned but some of the 'shills' might do so on his behalf. What if I can provide some research data that casts doubt on any 'motorcycle move' in the downswing? It might help your swing using the qualitative opinions of Monte and Tyler but is it really happening the way they proclaim? I can provide the graphs that show the flexing of the lead wrist for 97 golfers which may provide some rationale why Tyler Ferrell and Monte advocate the move. But I can also show you more accurate research data that proves there is no active flexing of the wrist and torqueing of the grip to close the clubface (in the downswing). That the closing of the clubface is more likely explained by Dr Sasho MacKenzies 'Moment Of Force' concept which will passively cause the clubface to square by impact. Addendum: Actually , on reflection and reading the research article again , I could be wrong about the 'motorcycle' move . Now , if the other Golfwrx forum members had argued their case with some logic, I would have accepted it but they just banned me without giving any reason at all .
  15. Golfwrx has definitely gone downhill and seem to ban members whenever they cast doubt on golf instruction especially if the golf instructor also happens to be a sponsor of their site. I can understand the financial reasoning but its not very good for golf instruction if people are banned for posting alternative opinions. There also seems to be a clique of forum members waiting to attack as a group anyone who does not conform to their ideas. They are especially sensitive (and fearful) about modern biomechanical research which is slowly progressing closer to the truth about the kinetics and kinematics involved in a golf swing . Think about it ! If golf science provides a more accurate model of cause and effect in the golf swing , then any 'qualitative' golf concepts being sold out there are virtually 'dead meat' (with the potential of severe financial loss). I regard the MSG as the mature adult while Golfwrx suffers from childish tantrums.
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