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Post by imperfectgolfer on Aug 1, 2020 18:48:01 GMT -5
UG, You wrote-: " I understand that not all pros do a prominent sit-down squat move, but I think all pros get to this body squared and arm back position during the downswing, and this is when they begin to demonstrate the fastest pelvis and torso rotation." I disagree! I think that the slope-speed of their pelvis rotation starts before P4, or at P4, and the slope of their pelvic rotary velocity graphs do not increase after ~P5, which is usually when the hip-squaring phase is completed. Here are the kinematic sequences of muliple PGA tour golfers. Look at their pelvic rotary velocity graphs showing that the slope of their graph is generally the same between P4 => P5 compared to P5 => P6. I do not see the slope dramatically steepen after a slow phase happening between P4 => P5 - as your statement " I think all pros get to this body squared and arm back position during the downswing, and this is when they begin to demonstrate the fastest pelvis and torso rotation" implies. In fact, Rory McIlroy's pelvis rotary speed graph is steeper between P4 => P5 than it is between P5 => P6. Jeff.
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Post by utahgolfer on Aug 2, 2020 0:45:41 GMT -5
Jeff,
It may be true that there is not a slow and fast phase of pelvic rotation from p4 to p5, but I would think that no pro seeks to reach maximum pelvic rotation speed as soon as possible or as explosively as possible. There is probably an optimal rate of pelvic rotation acceleration and I would assume it is not as explosive as possible, knowing that all of the body segments must be properly timed within the kinematic sequence (for a given player). Consequently, I would assume most players feel the hips rotating as fast as possible just after the pelvis squared, arms back position, and not immediately after p4.
The graphs are fine, but they still leave out so much information. They don’t show when p5 is happening exactly, or what % of maximal power is being generated at a given point, or which muscles are firing and when, or the degree of hip hinge occurring during the transition, or the amount of left hip ER that precedes pelvic rotation.
Of course, the graphs show angular velocity of the pelvis, upper torso, left arm, and club, and indicate the kinematic sequence. This is valuable and interesting, but it is far from complete.
UG
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Post by imperfectgolfer on Aug 2, 2020 6:33:06 GMT -5
Jeff, It may be true that there is not a slow and fast phase of pelvic rotation from p4 to p5, but I would think that no pro seeks to reach maximum pelvic rotation speed as soon as possible or as explosively as possible. There is probably an optimal rate of pelvic rotation acceleration and I would assume it is not as explosive as possible, knowing that all of the body segments must be properly timed within the kinematic sequence (for a given player). Consequently, I would assume most players feel the hips rotating as fast as possible just after the pelvis squared, arms back position, and not immediately after p4.The graphs are fine, but they still leave out so much information. They don’t show when p5 is happening exactly, or what % of maximal power is being generated at a given point, or which muscles are firing and when, or the degree of hip hinge occurring during the transition, or the amount of left hip ER that precedes pelvic rotation. Of course, the graphs show angular velocity of the pelvis, upper torso, left arm, and club, and indicate the kinematic sequence. This is valuable and interesting, but it is far from complete. UG Regarding the bold-highlighted statement, a golfer "feels" the pelvis reach peak speed at P5.5, but the rate of acceleration should be constant from P4 => P5.5 if one performs the pelvic rotary motion optimally. I don't personally like the "idea" of "exploding" the pelvis rotation after P5 in terms of attempting to accelerate the pelvic rotary velocity after P5. I prefer the "idea" of smoothly rotating the pelvis, using a constant acceleration pattern, all the way from P4 => P5.5 by contracting the right-sided lateral pelvic rotator muscles at the very start of the transition and by simultaneously pushing off the left forefoot in an away-from-the-ball target line direction. Jeff.
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Post by syllogist on Aug 4, 2020 6:36:13 GMT -5
Hi UG, If I interpreted them correctly, it's interesting how the velocity graphs show hips, chest, and left arm acceleration are at similar rates from P4 and shortly thereafter for most of the golfers shown. Your initial post in this thread was about lead hip ER as the first downswing move.We know that the chest turn is 45+ degrees more than that of the hips in the backswing and that the hip turn is 10 to 25 degrees more than the chest turn at impact. Refer to the links below from Athletic Motion Golf for its review of hip turn and the relative openness of the hips and chest at impact. The point about openness at impact is that the chest must rotate far more than the hips even though the hips are more open at impact. (My intent to highlight the videos has nothing to do with commenting on their teaching.) www.youtube.com/watch?v=M-8bk1zvTX8 (note the relative "centeredness" of hip turn of the pro vs. the overturn and lack of recovery by the am) www.youtube.com/watch?v=Z1I_PDs3DbA. (Note the relative degree of backswing turn of the hips and chest and their relative degree of openness at impact. Also note the Shawn Webb "gets what he gets" at impact when he makes actual swings without being aware of the degrees of openness when making static poses.) I don't view the downswing acceleration of hip turn as you or Dr. Mann. My view is that, in general, the intent of the tour golfer (whether or not such intent materializes) is to begin downswing rotation of the chest and hips together (as in "whole body" rotation). The golfer controls his initial rate of rotational acceleration. From that point on, what happens just happens (given whatever lateral hip motion there may be, meaning how uncentered the motion may be), i.e., the various rates of acceleration and deceleration of the hips, chest, and left arm. Keep in mind that the tour golfer reaches impact from P4 in 1/4 of one second. S
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Post by utahgolfer on Aug 4, 2020 20:14:14 GMT -5
Hi S,
Thanks for your insightful post. The two videos were also instructive and helpful.
It is clear the Am does not use the backswing to prepare for the downswing. He is completely out of position, pelvic rotation-wise, and this does not transition well into downswing. The Pro is the opposite.
To me, this confirms the idea that a proper backswing hip turn is a part of the transition move of the downswing. The trail hip must get deeper and rotate enough to be able to then perform the downswing pelvic motion correctly.
I also really liked the AMG Pro model showing the targetward pelvic shift at p4, another possible part of the transition (at least for some players, and as shown in Hogan's swing).
This then leads to the hip ER move or the sit down squat position, that some player's perform. Again, this is based on the preference of the player.
And, finally a proper opening of the pelvis at impact.
I believe only the first and last parts are essential. The player must rotate the pelvis correctly during the backswing to set up the downswing, and he must rotate the pelvis open an acceptable amount at impact. The targetward shift, the lead hip ER, and the squat move are optional and only need to be done if this helps to get his pelvis properly opened at impact.
That is the pelvis' story. Let me know if you agree or disagree with this interpretation.
How the chest and pelvis interact on a rotation basis is another topic, I believe. A given is that the chest needs to be squared or slightly open at impact. I agree the chest and shoulders have more ROM to cover, but they can also cover that ground more quickly. The bottom line is that, at impact, there needs to be some torso-pelvic separation with the hips more open than the chest and shoulders. Of course, the player needs to work this out. Just saying the shoulders or chest must rotate from p4 is good, however, the pelvis and chest rotation must sync up. Obviously, some players turn the pelvis too quickly or too slowly, and other players turn the chest too quickly or too slowly. I don't think we can just say turn both from p4 and we will see good results across all players.
It depends on what we see at impact and where the player is deficient. Some will need to get the backswing pelvic rotation correct. Some will need to get the pelvis more open at impact. Some will need to get the chest more open at impact. All will need to get a proper combination of the two.
UG
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Post by syllogist on Aug 5, 2020 8:08:48 GMT -5
Hi UG,
I'm glad that you saw value in watching those videos. These days, provided that the measurement systems are accurate, we can see many aspects of gross positional movements of the tour pros. Explaining how best to make these movements are another matter. What muscles (or body parts) to activate, what amount of force used to activate, and what not to activate can be quite perplexing. It is as if the golf swing is largely what one might call a problem solvable only through experimental physics, which is why it may approach the impossible to teach how to make an elite swing.
In the "clearing the hips" video, the am overturned his hips in the backswing and created a difficult position from which to execute the downswing. To overturn the hips, he had to activate muscles in that region of the lower body to turn them. What if he didn't activate those muscles and allowed the hips to turn solely as a result of having turned his chest? Absent issues with flexibility, would he then have looked similar to the pro?
When his chest is fully turned at the top of the swing and provided that he did not actively turn his hips in the backswing (to reduce his "X factor"), can he really begin to turn his hips in the downswing any meaningful amount in advance of his chest rotation? I doubt it. Next consider what happens when the pro begins to rotate his chest in the downswing ("how to open yourself" video). Provided that he does not actively try to prevent his hips from rotating, they will freely rotate in conjunction with his chest rotation. Consider too that they will rapidly "square" to the target line with no effort as the chest begins to rotate for they have hardly any distance to cover. As the chest continues to rotate, the hips will continue to freely rotate, which is why the hips will always be more open than the chest. The amount of openness of the hips vs. chest at impact likely has to do with factors that have nothing to do with intentionally altering through muscle control the relative speed of hip vs. chest rotation. Since the chest should be more open than the shoulders, I don't consider shoulder rotation as part of the sequence; they physically must go along for the ride when the chest rotates.
S
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Post by utahgolfer on Aug 5, 2020 10:45:32 GMT -5
S, you write well and provide good food for thought. We are all biased by what we feel and what works for us. I would predict that your bias reflects what works in your swing. I know mine does.
I am much more on the muscle activation side of things and that the player should have conscious or automatic control of his skeletal muscles and associated pelvic and chest rotation. If things are spontaneously rotating properly then it is muscle activation that makes that happen. To say that chest rotation dictates pelvic rotation is about 180 from what I believe. I do realize the rotation of one body segment can influence and facilitate the rotation of other body segments, but not at a level that promotes a competent swing. The body is a kinetic linked chain, but that concept has limited application.
Many touring pros probably echo your assessment. The swing just happens. But, this I believe, is because their muscles activate and joints move without thought. Proper muscle activation, however, has to behind the essence of every human motion, especially when it comes to coordinated motion that is precise and powerful.
I can definitely move my hips with a delayed and slow chest rotation, and this is due to poor torso muscle activation. I can also move my chest ahead of my hips, where the hips in no way can keep pace with my chest rotation. The pelvis must have muscle activation to turn properly. And, the only way for me to do it correctly is with proper muscle activation, at least this is my understanding.
UG
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Post by dubiousgolfer on Aug 5, 2020 11:46:28 GMT -5
Hi UG/S From a previous thread here is a nice diagram showing the muscles that predominantly rotate the upper torso. If the pelvis rotates before the upper torso during the transition phase of the golf swing, then the abdominal wall muscles (depicted in green) are stretched, and they can therefore potentially contract a greater amount/distance per unit time when those abdominal wall muscles eventually become active during the early downswing. In other words, the increased active muscle power of those stretched abdominal wall muscles could potentially increase the uncoiling of the upper torso and generate faster upper torso rotational speeds. DG
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Post by syllogist on Aug 6, 2020 9:41:56 GMT -5
Hi DG,
The problem with the "stretch" theory is the stretch. First, for there to be stretch, the hips must turn more in the backswing than they would be turned by merely the turning torso. Second, the hips would have to turn in the downswing and "reach their limit" before the torso begins to turn, i.e. no slack between hips and torso. Third, how much rotational speed can the torso gain than it otherwise would if there were no stretch? Lastly, the muscles used to turn the torso must still be activated at a high level to cause fast torso rotation.
Doesn't the "stretch model" imply maximum stretch while the 45 degree hips turn/90 degree chest turn is, in itself, sufficient stretch to allow for high-speed chest rotation?
I am wondering, for example, if young Nicklaus who had a large hip turn in his backswing with a prominent lower body movement to initiate the downswing created such stretch or whether all the lower body movement was somewhat "extraneous" and a carryover from his days as a baseball batter.
S
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Post by dubiousgolfer on Aug 6, 2020 10:28:10 GMT -5
Hi DG, The problem with the "stretch" theory is the stretch. First, for there to be stretch, the hips must turn more in the backswing than they would be turned by merely the turning torso. Second, the hips would have to turn in the downswing and "reach their limit" before the torso begins to turn, i.e. no slack between hips and torso. Third, how much rotational speed can the torso gain than it otherwise would if there were no stretch? Lastly, the muscles used to turn the torso must still be activated at a high level to cause fast torso rotation. Doesn't the "stretch model" imply maximum stretch while the 45 degree hips turn/90 degree chest turn is, in itself, sufficient stretch to allow for high-speed chest rotation? I am wondering, for example, if young Nicklaus who had a large hip turn in his backswing with a prominent lower body movement to initiate the downswing created such stretch or whether all the lower body movement was somewhat "extraneous" and a carryover from his days as a baseball batter. S Hi S I suspect golfers have different levels of muscle contraction in their abs and different stretch levels. If the golfer is very flexible and has large pelvic-torso separation capability, I could easily imagine that he might have to rotate his hips more to optimise the abs stretch to rotate the torso . But then there is always the danger that this could cause his right arm to be 'stuck' behind him (aka Tiger Woods old golf issue when he was with Butch Harmon). Not sure about JN but his big backswing gave him the opportunity to apply forces to the club over a longer distance (angular and linear). Further, if those forces could be maximised via the hands by creating more X-factor between pelvis/torso separation in 'transition/downswing' , then he's probably 'killed 2 birds with one stone'. DG
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Post by imperfectgolfer on Aug 7, 2020 18:27:59 GMT -5
S, You wrote the following comments in a recent post-: " It is as if the golf swing is largely what one might call a problem solvable only through experimental physics, which is why it may approach the impossible to teach how to make an elite swing." I believe that it is wrongheaded to believe that the full golf swing action is a problem that can only be explained via explanations based on experimental physics, and I also believe that it wrongheaded to believe that it is impossible to teach a student-golfer how to perform a golf swing like an elite pro golfer.
You also wrote-: "My view is that, in general, the intent of the tour golfer (whether or not such intent materializes) is to begin downswing rotation of the chest and hips together (as in "whole body" rotation). The golfer controls his initial rate of rotational acceleration. From that point on, what happens just happens. --- Next consider what happens when the pro begins to rotate his chest in the downswing ("how to open yourself" video). Provided that he does not actively try to prevent his hips from rotating, they will freely rotate in conjunction with his chest rotation. Consider too that they will rapidly "square" to the target line with no effort as the chest begins to rotate for they have hardly any distance to cover. As the chest continues to rotate, the hips will continue to freely rotate, which is why the hips will always be more open than the chest.
I disagree 100% with your opinion that a golfer should think of rotating the whole body together during the downswing - starting with a rotation of the chest. I think that if a golfer starts the downswing with a chest (upper torso) rotation, that it will produce an upper body dive action and OTT move - as depicted in the following image from the SLAP book.
You can sense that the golfer (model) is throwing his upper body outwards towards the ball in the above photo. Note that the right shoulder has moved horizontally outwards towards the ball-target line, and note that it is starting to cross over the toe-line in the early downswing. Note that the hands have been thrown away from the body and they are well forward of the toe-line. To complete the downswing and hit the ball, the golfer (model) has to execute an out-to-in hand swingpath by pulling his hands inwards across the body (in the direction of the blue arrowed line).
Here are capture images of an amateur golfer showing that type of golf swing pattern.
Note how the amateur golfer starts the downswing with an upper body movement (involving an outward motion of the right shoulder) that throws the hands and club over the toe line along a steep downswing path (image 1). Note how the steep "over-the-top" movement of the hands then produces an out-to-in clubhead swingpath through the impact zone as the amateur golfer pulls his hands inwards towards his body during the remainder of the late downswing and early followthrough (images 2, 3 & 4). Note how the club exits below the left shoulder in image 4.
Note that his pelvis is also rotating counterclockwise, but passively in response to the active motion of the upper torso. Note that his shoulders are turning too horizontally because most of the active spinal motion is happening at the level of the mid-upper thoracic vertebrae. Also, it is very common in this type of upper body dive swing action for the head to move targetwards in response to the counterclockwise rotation of the upper torso and it is often associated with leftwards spinal tilt as the "chest covers the ball" during the later downswing and early followthrough when the head moves ahead of the ball - see images 3 and 4.
To correct this problem, the beginner student-golfer needs to re-think his entire approach to the downswing, so that he can achieve the type of downswing clubhead swingpath used by the majority of professional golfers - as depicted in the following image from the SLAP book showing the optimum clubhead path in blue.
Note that the clubhead first moves backwards (away from the ball-target line and towards the tush line) before it descends along a shallower arc towards the ball along an inside track.
How does a student-golfer learn how to produce that clubhead path pattern? I believe that the correct answer is based on learning how to optimise his golf swing biomechanics - as demonstrated by Tiger Woods in the following capture images.
Image 1 is at P4, image 2 is at P5, image 3 is at P5.5 and image 4 is at P7.
Note that he has rotated his pelvis by ~50 degrees during his backswing action and his shoulders have rotated by ~ 100 degrees, so there is a difference of ~50 degrees.
Note that his pelvis has squared by P5, which means that it has rotated counterclockwise by ~50 degrees. Note that his shoulders have rotated by <50 degrees by P5 and that accounts for the fact that his right shoulder socket is far back and he has a very closed upper torso alignment at P5. I believe that this pelvic-upper torso alignment is only possible because he rotates his pelvis first and also more actively than his upper torso.
Note what happens between P5 and impact. Note that TW's pelvis is more open that his upper torso at P7, and most importantly note that his shoulders are rotating more vertically in a ferris-wheel manner, rather than a merry-go-round manner, and that requires the combination of i) increased secondary axis tilt where there is rightwards-spinal tilt and where the head remains behind the ball and ii) an increased degree of right lateral bend. I believe that a major biomechanical element that makes this biomechnaical combination possible is the straightening of the left leg and elevation of the left hip joint that happens between P5.5 and impact and it also requires a conversion from having anterior pelvic tilt at P5 to acquiring posterior pelvic tilt by P7.
All these described biomechanical actions (seen in TW's elite-quality downswing) are teachable to a student-golfer, but the student-golfer must first not adopt a a mindset that asserts that "what happens just happens".
Jeff.
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Post by syllogist on Aug 8, 2020 8:08:34 GMT -5
Hi Dr. Mann,
Remember that I stated that the "intent" is to start "whole body rotation."
Throwing the upper body outward as Mann depicted is merely upper body rotation around the wrong "axis." Might that movement inhibit "natural" hip rotation? If I tried that movement, it likely would.
In the second series of photos, looks to me as if the am's arms have come down quickly, stalling upper and lower body rotation, perhaps as if his intent was to "swing the arms."
In the last series of photos (Woods?), you've speculated what you believe he dd based on what you can observe. Personal experimentation has shown me that with the intent to rotate the chest or, whole body if you will (with relaxed hips that have not overturned (turned more than that which backswing chest turn has turned them), I require no applied effort for the hips to rotate in the downswing. And then for me, the hips continue to turn, outracing the chest while the chest turns. I am sure that I would be aware of a need to actively rotate my hips - the total distance they cover is far less than that of the chest. With a decent axis of rotation of the chest (or shoulders if you'd like), the only way for my hips not to rotate a sufficient distance is to try to keep them from turning.
As for experimental physics being an important part of the process of acquiring skill, think of the infinite number of variations at your disposal from set up to top of backswing to sequence and other options in the downswing. How can you know what works best without experimentation? And even with experimentation, you cannot know whether other untested variations will work better.
S
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