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Post by utahgolfer on Jun 29, 2020 16:21:36 GMT -5
What should be the first move of the downswing? Is it pelvic rotation or lead hip external rotation (ER)?
The standard kinematic sequence graph, although valuable, only shows the angular velocity during the swing involving the pelvis, upper thorax, lead arm, and club shaft. This can cause the instructor or player to think that other parts of the body are not important or not noteworthy. It might cause an instructor or player to think that the downswing begins with pelvic rotation, since the kinematic sequence doesn't show what the entire body is doing.
We see in many professional swings, a purposeful leading or bowing of the left leg to start the downswing. Visually it appears to happen before any significant pelvic rotation. See Hogan (at 1:04) and Lines (at 3:05):
We know that during the downswing the left pelvis is turning CCW on top of an essentially stable left femur. We call this left hip internal rotation, since in a relative sense, the left femur becomes more and more medial compared with the left pelvis.
However, to begin the downswing, many pros first perform left hip external rotation and then perform left hip internal rotation after that. Why? A hip that is in more external rotation has the ability to then do even more overall internal rotation, and can probably do so more easily and more effectively.
Lead hip external rotation at the beginning of the downswing, on the other hand, involves mostly the movement or rotation of the femur under the left pelvis. This motion causes the left knee to bow outward with the left patella also rotating outward. Since the left pelvis is stationary or only slowly moving, the left femur becomes more and more lateral compared to the left pelvis (defined as left hip ER). In a sense, the left femur is "getting out of the way" so the upcoming CCW left pelvic rotation can be fast and effective.
Early in the downswing, left hip ER gives way to left hip IR, and the initial left hip ER gets the left femur out of the way so the left pelvic can rotate CCW unimpeded and with a full range of motion.
However, there may be other possible benefits to the initial and brief left hip ER at the beginning of the downswing. For example, it seems logical to believe that the initial left hip ER motion can help to prevent OTT path issues. When the pelvis complex rotates immediately at the beginning of the downswing, it is common for the right shoulder to rotate CCW as the same time, pulling the hands across the swing plane line. A proper left hip ER at p4 with very little pelvic rotation, and some arm drop motion (see Hogan's and Line's swing) may help alleviate or prevent OTT path issues. It might also be a good time to shallow the club shaft and palmar flex the left wrist, depending on the player.
Another nice feature of the initial left hip ER move is that it does not cause any weight pressure shift from the right to left foot. This is important to ensure proper stability of the right leg, proper activation of the right hip ER muscles, and proper CCW rotation of the right pelvis, which gets the entire pelvic complex rotating CCW during the downswing.
I can definitely see why left pelvic ER is important to lead the downswing. There appear to be many benefits. However, I'm unsure why a golfer would gain any additional benefit from doing dual hip ER (or the Sam Snead move). The Ben Hogan left hip ER move seems good enough to me. It is simple and effective. To best prepare the right hip ER muscles for an upcoming contraction, wouldn't it be best to keep these muscles at a normal length. Why would a player want to shorten the right hip ER muscles (via dual hip ER) immediately before a concentric (shortening) contraction? Perhaps, some instructions would suggest that dual hip ER helps to weight pressure load the left and right foot, which could be true, but I think flexing the right hip or knee could do the same thing. I can see value in only performing left hip ER early in the downswing, but not dual hip ER.
Consequently, I believe the first downswing move should be lead hip ER, and not pelvic rotation as many instructors and players believe.
UG
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Post by dubiousgolfer on Jun 29, 2020 18:53:52 GMT -5
Hi UG The intricacies involved is complicated but explained in Dr Mann's chapter link below: www.perfectgolfswingreview.net/pelvicrotation.htmlIn the early downswing while the right hip/leg is pressure loaded , both the right and left pelvic girdle rotary muscles are contracted. But because the left leg is relatively 'unweighted', the left pelvic rotary muscles will just rotate the left femur into external rotation. That's why you might see the left hip ER before the pelvic rotates. DG PS. There may be some assistance by the impetus created in that ER motion , because in the 2nd phase of the downswing (after the hip squaring phase) , the golfer can isotonically contract the 'Adductor Magnus ' muscle which can help pull the "left inferior pubic ramus (and therefore the left side of the lower pelvis) closer to the left femur" Dr Mann has a question and answer section in that chapter that is worth reading: Question number 5: If a golfer decides to use the pro golfer's pattern of rotary pelvic motion during his early downswing action, should he move the left knee targetwards before he starts to rotate his pelvis counterclockwise? There is another chapter that goes into even greater detail: www.perfectgolfswingreview.net/spinalmotion.htmSubtopic b: What do you think of the opinions expressed in the Somax Performance Institute's video analysis of Rory McIlroy's swing action?
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Post by utahgolfer on Jun 30, 2020 9:33:13 GMT -5
DG, thanks for your input. I appreciate the references back to Dr. Mann's material. I choose to not view these before discussing an idea so I can go with my current thinking, whether valid or not. I certainly don't pretend to know all the complexities. This may seem like an inefficient way to learn, but I need to make my little statements (current observations) and see where it goes. It helps me consider new ideas and fine-tune my current thinking.
In looking over this review paper, I especially liked the gif animation of Bubba Watson, showing his initial lead hip ER. Wow, that hits the nail on the head as an excellent example. I also appreciate that some golfers don't internally rotate the left hip during the backswing as much, so they may need less overt left external rotation to get their femur out of the way at p4. I also assume that a player with exceptional left hip internal rotation ROM, excellent hula hula separation, and overall fluidity of movement may not need to perform the initial left hip ER move, but it is still a very common trigger to begin the downswing across professional golfers.
When considering the Somax claim that this initial move can increase swing power, I now see things differently. Yes, by itself, this move does little to increase power. But, as a primer to allow for fast and unimpeded left hip IR, by getting the femur out of the way, it may certainly help to increase swing power as part of the collective movement.
But, I am most excited that this initial move may be an effective way to minimize or prevent OTT issues, which is an accuracy issue.
So, in the end, this initial left hip ER movement pattern at p4 may serve to increase both power and accuracy.
UG
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Post by utahgolfer on Jun 30, 2020 9:43:06 GMT -5
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Post by dubiousgolfer on Jun 30, 2020 11:49:41 GMT -5
Hi UG
" A proper left hip ER at p4 with very little pelvic rotation, and some arm drop motion (see Hogan's and Line's swing) may help alleviate or prevent OTT path issues. It might also be a good time to shallow the club shaft and palmar flex the left wrist, depending on the player."
So are you favouring an arm drop release of PA#4 at the start of the downswing rather than an active pivot ? But can't the golfer just drop the arms without any left hip ER and still prevent an OTT?
Shawn Clement also promotes an arm drop but I cannot see how it will increase clubhead speed. Clubhead speed requires torque so if you want to 'drop' the arms won't that involve 'no torque' being applied and reduce clubhead speed?
DG
Here is an old video by Shawn Clement but he never mentions the detailed biomechanics involved in 'falling' downplane which I think is an inaccurate term because that implies 'freefall' and allowing gravity to power the swing (which is incorrect because it only has a small effect). He doesn't get involved in biomechanics and uses task analogy feels which might be a different way of teaching the golf swing.
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Post by utahgolfer on Jun 30, 2020 19:25:02 GMT -5
Hi DG,
I'm recommending whatever Hogan, Lines, and Bubba are doing.
My concern is directed at the advice to turn the pelvis CCW from p4, as fast as possible, as the first move of the downswing.
When done with the initial left hip ER move, the pelvis move a little, but I don't believe this is an active pelvic rotation pivot yet. The shoulders turn CCW as the left arm moves downward, so the motion of the left arm looks to be pivot driven. As such, the left arm does not move without accompanying shoulder motion.
From what I see, Hogan et al. perform a truly active pelvic rotation after p4, and maybe as late as p4.5. I don't see the right hip ER muscles being fully active until after this initial left hip ER move.
It appears the pelvis motion has two phases. The first is a reactive response to the left hip ER move. The second is the active rotation of the pelvis using the right hip ER muscles.
Most importantly, I don't see these players rotating the pelvis as fast as possible from p4 as an attempt to move the left arm down the inclined plane as fast as possible. Rather, I see a preparation phase to get ready and optimize the active pelvic rotation phase, and then I see a fast rotation of the pelvis and the accompanying pivot driven left arm swing.
UG
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Post by syllogist on Jul 1, 2020 6:51:07 GMT -5
Hi UG,
My personal opinion - "leading" the downswing with a fast, active firing of the pelvic girdle accomplishes nothing except to get the hip turn too far advanced for "simple" chest rotation. The hips already have a head start given that they've turned approx. 45% in the backswing. If you consider the Hogan video you posted and Hogan's admonishment about "turning the shoulders" to start the downswing, rotating the shoulder girdle can certainly leave the hips behind to do nothing but pure chest rotation brings the hips "along." I see left leg ER and pelvic rotation as a "natural" consequence of pivot-driven chest rotation.
This discussion reminded me of Paul Bertholy's notion of "proper sequential motion," which he came up with from watching fabulous golfers such as Hogan. Paul advocated a "buckling" of the left knee as the first movement of the downswing. However, usually you don't see the "aesthetic" lower body action of a golfer who starts down with an independent turn of the shoulders accompanied by a firing of the arms.
S
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Post by dubiousgolfer on Jul 1, 2020 8:25:23 GMT -5
Hi UG/S
The kinematic sequence graphs by Phil Cheetham definitely show the pelvis moving first during transition.
This particular kinematic sequence graph shows the slope of the pelvis graph (ie. its angular acceleration) increases up to a max at P4 , then decelerates. So the pelvis is starting to turn CCW just before P4 is reached.
UG's comment below is quite interesting with respect to left leg ER happening before pelvic rotation (at transition)
"I see a preparation phase to get ready and optimize the active pelvic rotation phase, and then I see a fast rotation of the pelvis and the accompanying pivot driven left arm swing."
I was watching this video below showing some fantastic slow motion video of Sam Snead and found the section regarding the ballet dancer rotation move quite intriguing.
Look at the rear view of Sam Sneads swing (from 4:41 - 6:30) and then the ballet dancer creating a squat (see frame 6:04) . From a physics perspective , note that the ballet dancers feet are flared and he has created a greater MOI by stretching out his arms and knees around a vertical central axis of rotation . He can now use contractions of his core muscles and shear forces (between his feet and ground) to create some instantaneous angular momentum (with that large MOI). As he quickly brings/snaps his knees together (just after creating that initial large angular momentum), it decreases the MOI but increases the angular velocity of his body/outstretched arms .
So 'theoretically' , it looks like the squat move could be a preparatory stage to creating an increase in the angular velocity of the 'pelvis/torso /left shoulder socket' with an increased pull on the left arm . The golfer does the 'squat' move , then the 'snap' move by internal rotation of the femurs in their hip sockets while bringing the knees closer together (the presenter calls it the 'squeeze pivot') to assist in the increase of the angular velocity of the 'pelvis/torso' pivot.
Obviously , there is no evidence that this is actually happening but its an intriguing possibility and I suspect more applicable from P5 just after the 'hip squaring' phase of the downswing. I still think many PGA pro golfers use a contraction of their internal/external obliques to release the left arm from P4 via an upper body pivot and that its assisted by a connective muscular 'stretch' by the rotating pelvis.
DG
PS. When I look at Phil Cheethams kinematic graph in that video, it seems to show that the angular acceleration of the pelvis /ribcage decreasing after P4 , therefore the above doesn't make full sense. Maybe the 'squeeze pivot' theory could be a means to try and maintain the angular velocity of the pelvis/ribcage or limit their deceleration by P7.
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Post by syllogist on Jul 2, 2020 7:01:27 GMT -5
Hi DG,
Snead's swing was quite good. I don't think that the squat move was as remarkable as the narrator of the video made it out to be. At the top, Snead's left knee pointed rightward quite a bit. As soon as pelvic rotation starts, the left leg is going to externally rotate and such will appear to be more pronounced the more the left knee was made to point rightward. To leave the knee behind while the pelvis rotates would require concentration. :-)
I wouldn't doubt it if the term "turn in a barrel" came from watching Snead. He has a very "centered" rotation and looks to make the most of "efficiency of rotation." You see with Snead a lower body rotation where the left leg rotates "behind" him and snaps straight in a pronounced fashion. Well, he did have quite a bit of rotational speed as he went after that ball.
S
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Post by dubiousgolfer on Jul 2, 2020 8:43:55 GMT -5
Hi DG, Snead's swing was quite good. I don't think that the squat move was as remarkable as the narrator of the video made it out to be. At the top, Snead's left knee pointed rightward quite a bit. As soon as pelvic rotation starts, the left leg is going to externally rotate and such will appear to be more pronounced the more the left knee was made to point rightward. To leave the knee behind while the pelvis rotates would require concentration. :-) I wouldn't doubt it if the term "turn in a barrel" came from watching Snead. He has a very "centered" rotation and looks to make the most of "efficiency of rotation." You see with Snead a lower body rotation where the left leg rotates "behind" him and snaps straight in a pronounced fashion. Well, he did have quite a bit of rotational speed as he went after that ball. S Hi S Personally , I don't think there is much of an effect on any increase in pivot rotation due to to this 'squeeze pivot' move (but I suppose it might assist in some small way). If you look at the dancer he kept his feet very close together and his knees bent outside of the perimeters of his feet (that doesn't happen with a real golfer). So any change in MOI would be minimal in my humble opinion. DG
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Post by syllogist on Jul 2, 2020 9:33:10 GMT -5
Hi DG,
The dancer does keep his feet close together, probably for ease of remaining vertical during the spin. On the other hand, a figure skater swings a leg around from a wider stance to gain momentum for the spin and does not remain vertical during the spin. I agree with your last comment about MOI.
S
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Post by utahgolfer on Jul 2, 2020 11:21:36 GMT -5
Hi DG and S,
What a wonderful video example of Snead. I also like the ballet example and the use of the word: preparation.
S thanks for your input, but I think this topic is very important for many golfers.
The idea is to prepare for a fast and effective pelvic rotation. The preparation phase is essential for this, as illustrated in the Snead video. It doesn't happen without instruction in many golfers, as they will straighten the left knee/hip at the beginning of the downswing and unknowingly greatly hamper their overall pelvic rotation.
It is true that the left femur and left pelvis can move together, but I doubt Snead and Bubba would do this preparation phase unless it helped in some way. I don't think it is a simple personal preference, or an individual oddity.
I believe the left pelvis can rotate CCW on top of a more stable femur, much more effectively, when the left femur is flexed and when the left femur is externally rotated. Try rotating your left hip CCW when the left femur is straight with no hip flexion. Do the same when the left hip is externally rotated versus internally rotated. It is easy to see that both matter a lot...for a faster, longer, and more effective pelvic rotation. The importance of this preparation phase surely varies depending on the player's mobility and stability, but it is seems smart to teach all players to increase hip/knee flexion and hip external rotation at p4 to optimize pelvic rotation.
It is also intriguing that open to closed knees during the downswing increases the MOI to improve body rotation. Again, Snead probably used that right knee to his advantage, too. But, I do believe the left leg action is more important than the right leg in producing an optimal pelvic rotation.
Of course, the pelvic/torso rotator muscles are probably active at p4 when all of this is taking place, but I would bet they don't fire 100% until the time is right and when pelvic rotation is purposely optimized by the actions of the golfer.
UG
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Post by utahgolfer on Jul 7, 2020 14:55:59 GMT -5
Here are some added changes/new insights to this thread:
I have wondered if the title should be changed, but I currently would stick with it. The title is mostly a swing cue for me, but I assume many golfers could benefit from this approach. Not all golfers need to do lead hip ER first thing in the downswing, as they have a hip joint structure and accommodating muscles that allows for a fast, fluid, and long lasting pelvic rotation without getting the lead femur out of the way. However, this lead hip ER to start the downswing is very useful to me and obviously many other golfers.
I actually did the Sam Snead squat move several years ago with success, but I stopped doing it because the added hip flexion before hip extension created some low back pain. At the time, I did it for two main reasons: to prevent early hip extension and increase ground reaction force to possibly increase swing power. As it turned out, it was a good antidote for early hip extension and it provided a stable base of support. I didn’t notice much of an increase in swing power, but it was effective in preventing early hip extension. I would have kept doing it had it not caused some low back issues.
In the Milo Lines video, posted earlier, he essentially said that initial left hip ER gets the femur out of the way so the hips can turn better and longer. I had never heard of this before and decided to give it a try. As I practiced, I didn’t even think of the Sam Snead squat move, since I was only working on left hip ER. Of course, Sam Snead did both dual hip ER and hip flexion at the same time. In Milo’s videos, he also recommends opening the left knee and “reflexing” the hips and knees at the start of the downswing (a sit down move).
I have now made the left hip ER motion into a repeatable swing habit, and can enthusiastically say I agree with Milo. I also do a little right hip ER (dual hip ER), and probably a little hip hinge (sit down) motion, even though I don’t purposely try to hip hinge. Milo was correct--initial left hip ER does get my left femur out of the way and opens the door to better pelvic rotation. Focusing on left hip ER has also not created any back pain, and may even decrease the load/stress of pelvic rotation.
Two drills helped me establish initial left hip ER at the top of the downswing:
1) At address, with the left foot motionless, move the left knee inward (hip IR) and outward (hip ER) as much as you can. Feel the motion through the left hip joint. Notice how the knee cap rotates inward, then outward, as the thigh moves back and forth. This drill can also be done right before a shot, as part of your pre-shot routine, similar to how Matthew Wolff chooses to rotate his pelvic before starting his swing. However, in this case, the only motion would be to do left hip IR and ER.
2) Pause at the top of the backswing and do the same. Move the left knee inward (hip IR) and outward (hip ER) as much as you can. Feel the motion through the left hip joint and notice how the knee cap rotates inward, then outward.
It took a few days of practice to improve my independent left hip ER/IR motion, but it has been relatively easy to incorporate this motion into my actual golf swing.
At this point in my learning/experience, I still agree that pelvic rotation has both a preparatory and power phase. I was in error to say the pelvis doesn’t rotate until after the left hip ER move. It obviously does but the relatively slow CCW pelvic rotation is preparatory and not powerful in its purpose. The power phase of the pelvic rotation is delayed so the left femur can get out of the way and pelvic rotation can occur as active, fast, and long-lasting as possible.
I believe it was Ben Doyle who taught the “catching a pig between your legs” swing tip. The idea is to separate the knees (dual hip ER) to let the pig run between your legs at the beginning of the downswing, and then to quickly pull the knees closer together to catch the pig by its tail before it gets away. The preparatory phase is to separate the knees (dual hip ER) which will promote relatively slow pelvic rotation and gets the left femur out of the way. The power phase, on the other hand, is to quickly rotate the pelvic/hips to bring the knees together. This allows the hips and knees to move quickly from flexion to extension. It allows the knees to move quickly from wide to narrow (to catch the pig) and maximize the MOI. It clearly represents the power phase of pelvic rotation.
I also still agree that left hip ER/dual hip ER helps to minimize OTT issues. The preparatory phase of hip rotation involves a slower and less active hip rotation. That means there will be less rotational energy being directed up the spine that could ultimately cause the right shoulder to move too horizontally or OTT. Of course, early rotational activation of the upper torso can cause an OTT issue regardless of what the pelvis/hips are doing, but aside from this problem, the slower preparatory phase of pelvic rotation is inherently designed to minimize OTT issues.
As we know, the body is a connected kinetic chain, and one movement can influence others up and down the kinetic chain. Recently, I had been straightening my left hip and knee immediately at the beginning of the downswing, as I would start my pelvic rotation. I also wondered why my left shoulder was elevating so early and quickly in the downswing, leading to a host of swing path issues, hanging back problems, and inconsistent ball contact since the swing would bottom out too early. Of course, the early straightening of the left leg caused my left pelvis to elevate, which caused my left rib cage to elevate early, which caused my left shoulder to elevate early, which caused early right lateral spinal bending.
Learning the initial left hip ER move helped to solve this problem immediately. My left shoulder now doesn’t elevate early, so I have been able to minimize swing path errors, hanging back problems, and poor ball contact issues.
I now realize the Sam Snead squat move is a lot more than just the “sit down” move. I think its most important part is left hip ER. I think left hip ER should be done first. I think dual hip ER happens as a result of left hip ER. I think the sit down move happens as a result of left hip ER. I believe getting the left femur out of the way is the key component for the many golfers who have trouble rotating the left pelvis around a neutral or internally rotated left femur.
I had one of my best ball striking days yesterday playing golf with Jeff at the South Mountain golf club in the SLC area. I basically had two swing thoughts: left hip ER and let the relaxed arms fall downward via the power phase of pelvic rotation.
Milo is correct on this very important swing mechanic. It leads to increased accuracy and power and it all makes good sense. I plan on catching pigs by the tail for many years to come!
UG
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Post by dubiousgolfer on Jul 7, 2020 17:22:51 GMT -5
Hi UG
Many thanks for that detailed post and I really like the term 'to catch the pig' . I think I'll give it a go the next time I ever get to play golf again - not played for over 9 months now. But I might practice some of the drills in my back garden just to see how left hip ER feels on my inflexible back.
DG
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Post by dubiousgolfer on Jul 8, 2020 8:35:19 GMT -5
Hi UG
Did you mean minimise MOI in the your sentence below ?
"It allows the knees to move quickly from wide to narrow (to catch the pig) and maximize the MOI. It clearly represents the power phase of pelvic rotation."
DG
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