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  1. On further investigation about the AMG video I posted regarded early extension , I have been contacted by a 3D expert in GEARS who advises that those measurements cannot be made in GEARS system. That the only way the AMG team could have produced those angle values were by using avatar images , putting dots on them and then measuring with a 2D tool. He also advises me that AMG have produced many good videos but also unbelievably poor ones too , sometimes for marketing purposes. I don't blame AMG for marketing their product but they must be very careful producing videos that may give golfers inaccurate data or false perceptions.
  2. On another matter , I have been looking again at Dr Sasho Mackenzie's 'Intro To Kinetics' video . https://vimeo.com/158419250 I think the following 2 screen images might confuse people who don't really understand how a 'pure couple' (applied via the hands) moves the club. If you look at the 1st screen, I have highlighted a bullet point in a red box. Note what is says regarding a couple , that it has "no net effect on linear motion' . This means that a couple applied at the grip will not move the COM of the club in a linear direction (the COM cannot move in space). But if you look at the 2nd image , he has drawn (by mathematical convention) the couple 19 Nm about the mid-hand-point . A person seeing that image might assume that the club is being rotated about that mid-hand-point but that is incorrect . That couple would cause rotation of the club about the COM which I have added into the image (see green rotation arrows around the COM). I think one has got to be careful assuming how forces and couples might move the club when using inverse dynamics, because it could give a false 'feel' perspective.
  3. Maybe , but no-one can 100% categorically know cause and effect in the golf swing, not even Monte Scheinblum. Golf instructors can try different fixes, and if it works , fine. The fact that one can measure/identify EE in a golf swing is a signpost that something may be going wrong. My point is pelvic thrust is not the only kinematic variable that should be used to identify EE.
  4. Here is another issue about defining early extension. Look at the Sportsbox video with Dr Phil Cheetham from 20:20 , who seems to infer progressive pelvic thrust (ie. forward towards the ball-target line) in the downswing , or retention of any pelvic thrust in the downswing (done during the backswing) is a sign of an early extension fault. https://www.youtube.com/watch?v=2vlbCyjLzLU But I think its more complicated than the above to define an EE (early extension) fault, which is also defined by EA Tischler below: https://www.youtube.com/watch?v=fW9Xhim4uoY Further , Dr Jeff Mann has another opinion: "When I think of the swing fault of 'early extension', I think of the the pelvis going from a condition of anterior pelvic tilt to a condition of posterior pelvis tilt and it is a 'standing-up' phenomenon because if the pelvis moves towards posterior pelvic tilt then a line drawn perpendicular to the pelvic axis between the upper sacrum and the symphysis pubis becomes more vertical. That 'early extension change can occur with, or without, a pelvic thrust motion in the direction of the ball-target line. It is also possible for the center of the pelvis to move towards the ball-target line without any change in pelvic tilt angle - and that would not represent an 'early extension' swing fault. Phil Cheetham's graph is measuring pelvic thrust, and it is not measuring changes in the pelvic tilt angle." The above EE fault as explained by Dr Mann happens before P5 in the downswing. The description of anterior and posterior pelvic tilt is explained in this video by Dr Greg Rose: https://www.youtube.com/watch?v=SU-MQnnP4Ts Here are examples of 3 golfers pelvic tilt (red line) and pelvic thrust (green line) during their golf swing: My own translation of those graphs are as follows: 1st graph - it seems that the golfer has anterior pelvic tilt during the downswing , loses that slightly in the early downswing , then increases slightly again in the late downswing. So not much change from original address position which has 13 degrees anterior pelvic tilt. Yet he/she has also thrusted their pelvis towards ball-target line in the backswing and has generally retained that thrust value throughout the downswing. So in effect , that is a net forward thrust without any increase in posterior pelvic tilt . According to the definition in my opening post, that would not be deemed to be early extension. 2nd/3rd graphs - show no increases in posterior pelvic tilt in the early downswing (ie. before P5), and no significant pelvic forward thrust (ie. butt cheeks not moving towards ball-target line and kept against the 'wall/tush line'), therefore no early extension. So, according Dr Mann's definition (and probably EA Tischler) we might conclude that none of those graphs are showing 'EE' even though there is obvious pelvic thrust happening early in the backswing for 1st graph. Early extension needs to be clearly defined before being used as a swing fault explanation. PS. Here are some additional graphs showing typical pelvic tilt for typical PGA/LPGA players.
  5. Checking out that AMG video again, now I think their measurements are flawed because their camera was only moving from a changing DTL view and not normal to that triangular plane (as per my eye drawing in previous post). Therefore, they will be measuring projected angles rather than the real 3D angles. So for example, in reality the lead side triangle might actually be increasing just before impact from the 'eye' view , but because that triangular plane being tilted away from the target, its projected angle might show a decrease due to parallax.
  6. This new AMG video about early extension is interesting but I don't know if there is any scientific validation in the way they define it for the lead and trail side of a golfer. Early extension is usually defined as the centre of pelvis thrust towards the ball-target line , usually in the backswing and early downswing . AMG are using strange marker point placements in the centre of the chest , the hip and knee joints. https://youtu.be/yepkMQdy0Z4 The angle they are measuring is generally an obtuse angle of a triangular plane formed by those 3 marker points (see image below for the trail side triangle only but obviously there will be one on the lead side too). Anyhow , quite an interesting video.
  7. What proof do you have that Rory's use of grfs is responsible for his driving distance? A golf biomechanics scientist who is an expert on GRFs is Dr Scott Lynn and he sent me an email saying the following: "Thanks so much for your email. You ask some really good questions that I don’t think anyone has the answers to yet. I’m not aware of any published work that has been done to date where the GRFs have been measured on the same swings where club inverse dynamics analyses were run so that the calculated club/hands kinetic values could be related to the measured GRFs. Hopefully this type of work will happen soon as this would really help our understanding of golf swing mechanics." Dr Kwon thinks there is a grf cause and effect to clubhead speed in his research articles but I've also read articles by other scientists who state no correlation.
  8. With regards the extent of the straightening of the trail arm check out Justin Thomas below: He has a spinning pelvis action and outstretched lead arm such that the angle between his lead arm and shaft is almost 180 degrees at impact. Look at his trail elbow bend just before P6 , its about 10-15 degrees more than a 90 degree angle between his forearm and upper arm. Now look at Sergio Garcia Image 2 is club horizontal in the downswing (P6) and his elbow has straightened significantly more than JT . Also his lead arm plane is more vertical and the shaft makes an angle with his lead arm far less than 180 degrees at impact (image 4). Here is Milo Lines He's another golfer who has outstretched lead arm and has not straightened his trail elbow by much Here's a selection of golfers at P6 with varying trail arm elbow bend and I suspect it's related to a whole range of variables in their swing . Image 1 = Justin Thomas; image 2 = Tommy Fleetwood; image 3 = Adam Scott; image 4 = Rory McIlroy; image 5 = Brooks Koepka, image 6 = Dustin Johnson
  9. It might be helpful as a feel for some , but I think the amount of trail arm straightening is dependent on other variables that the golfer finds biomechanically natural for them. Not all golfers might benefit from the Justin Rose drill or MS's feel image below. Further, if they overexaggerate and ingrain that specific movement, they might end up hitting fat shots. With regards AMG videos , I don't know over what sample of golfers 3D data they've used but maybe they should publish it before claiming this is what PROs do vs AMs. I will check if there is any average 3D data on trail elbow bend vs time with Michael Neff and Dr Phil Cheetham (or even Jon Sinclair) as they have 100's of pro golfer data on their GEARS and AMM3D systems. Also , MS sort of denounced X-factor but he needs to be more careful, because X-factor is important for creating clubhead speed but the way it's created (ie. purposely restricting the rotation of the pelvis) might not be the optimal way (see video below with Dr Phil Cheetham - renowned golf biomechanics scientist). https://www.youtube.com/watch?v=-UbtLZo2Wos In fact, Dr Cheetham says the X-factor is equally as important as X-factor stretch.
  10. There are a few things in MS's video above that doesn't make sense to me. 1. The straightening of the trail arm in the downswing to P6. I don't see that happening to any great degree in many golfer swings although I'm open to seeing any evidence that can prove it. 2. He doesn't make it clear whether he is defining shoulders separately to the chest . I am assuming he thinks it's one and the same although the shoulder girdle sits on the ribcage (just like a large overcoat sits on your torso). The shoulder girdle and chest can move independently within a certain degree of range of motion and can have its own 'x-factor' stretch. From 38:21 he talks about x-factor stretch, about the separation between the hips and shoulders during transition. I am assuming he really means separation between chest(thorax) and pelvis during transition (not the shoulders). As far as I am aware , there can be X-factor stretch created between the shoulder girdle muscles and the chest , also between chest and the pelvis and also between the wrists and the arms. 3. MS says almost universally in elite golfers, by the time the swing gets to left arm parallel (ie. P5) in the downswing the left arm is accelerating from the chest. He says learn how to do this by looking at "Rory McIlroy where his chest does not turn, that's how he hits the ball so far. He turns his hips a good 30 degrees and drops his arms maybe this much before his shoulders start to turn." " The longer you keep your chest closed and stay in left tilt, that creates the big x-factor stretch and allow the left arm to accelerate away from the chest" I am assuming he is using the same info/opinion from Michael Neff (founder of GEARS) about Rory that is mentioned in this video below at 18:44 -23:50 https://youtu.be/xyxfFZfL7Fg But the distance that Rory lowers his arms/hands is nowhere near the exaggerated distance MS infers in his video. Also Michael Neff never once says that Rory has stopped turning his shoulders/chest during the downswing. I'm not sure that retention of left lateral spine tilt and that 6 inch drop of the arms in the early downswing can explain in totality why Rory hits the ball so far. I'm more likely to believe it's a lot more complicated and involves many other variables in his golf swing mechanics. If you look at Rory's kinematic sequence graph below on the left , can you see the 'green line' (ie. his chest/thorax) rotating at zero degrees per second in the early downswing (ie. moving along the horizontal time axis)? If no , then his chest is rotating and hasn't momentarily stopped. I'm sure the lead upper arm is starting to accelerate quicker than the chest in its own 3D plane as the early downswing progresses and that is probably due to assistance by trail upper arm adduction.
  11. This seems to be the left forearm flying wedge concept that TGM (The Golfing Machine) uses. The 'ideal' is to always have the shaft tracing the ball-target line in the backswing and downswing. Obviously that can't happen when the club is parallel to the ball-target line (ie. P2 , maybe P4, P6). The right arm/wrist/hand is being used support the left forearm flying wedge to always be 'on plane' (ie. shaft tracing the ball-target line) even as the club shaft may change plane angles (see images below). As an example , lets assume the above golfer was swinging 'On Plane' during the downswing . As his downswing progresses, the shaft swing plane changes from the blue to the red line , but it would still point /trace the ball-target line . Look at the Anthony Kim images below where the shaft is moving from a steep to flatter plane while he retains the left forearm flying wedge but the shaft is still 'On Plane' all the time because the shaft is tracing the ball-target line. The right 'arm/wrist/hand' is supporting the intact 'Left Forearm Flying Wedge to keep it 'On Plane' (see image below where I've drawn the red triangle LFFW . Seems like a simpler qualitative concept for performing a golf swing. With regards the AMG video about their definition of shallowing the club , that's not how I perceive it . I regard shallowing the 'club's instantaneous swing plane' relative to the 'instantaneous hand plane' like DJ and RF below. The red line is his hand path and its obvious that the club is shallowing relative to instantaneous hand path/plane. Phil Mickelson shallows his club according to the AMG definition which is the angle the shaft makes relative to the ground but he doesn't according to the definition that I've been using. Here is PM whose shaft swings closely to his hand plane , therefore isn't shallowing (according to the alternative definition). There is no consensus of opinion about many terms used in the golf swing and 'Release' and 'Shallowing' are a few examples.
  12. Shallowing a club is a whole new can of worms . 1. How do you define it . 2. Why do it ? What are the pros and cons? 3. If there is a valid reason for doing it , how and when do you do it?
  13. Hip depth could be related to the anatomy of your hips but I suspect you could flare your right foot a bit if you really wanted to (which might help). But even little tweaks can affect other elements of your swing , so be careful going down a road which might make things worse.
  14. Why do you think your swing is flawed when your a 2.2 Hcp? Many of us will never improve our handicap to anywhere near your achievement. Addendum: Just read an earlier post from you showing your handicap has increased to 6+ but that's still very good. In fact , after reading through more recent posts , it's gone down to 2.8 so it varies by only about 3 or 4 over a period of 2-3 years.
  15. So NTC is teaching something that doesn't gel with what Monte is saying on those videos I posted?
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