DG,
You asked-: "
If the left leg is in external rotation and the left knee angled more targetwards, won't increasing its flexion slightly cause the pelvis to move slightly towards the target line and also slight left-lateral pelvic shift?"
If the left leg is unweighted at P4, and if one simply externally rotates the left femoral head in the left hip joint without attempting to deliberately move the pelvis, then the left knee will move targetwards if one does not attempt to significantly change the degree of left knee flexion. The left pelvis will consequently drop groundwards as a result without there being any significant left-lateral pelvic shift.
You asked regarding the following image-: "What are the biomechanics involved in the 'natural' left-lateral pelvic shift that could explain R1 moving to R2 in a 'Pro Golfers Pelvic Motion' in your website diagram below? Does George's move provide a possible explanation for that R1 to R2 movement?"
Most pro golfers have rightwards pelvic-loading motion during their backswing action. Then, when they rotate their pelvis counterclockwise during their hip-squaring phase that happens between P4 => P5, they often simultaneously shift their pelvis slightly targetwards. I will show you 5 examples shortly when I examine the "real life" pelvic motion of 5 different PGA tour golfers.
George Gankas claims that he can shallow the clubshaft between P4 and P5 without using any external rotation of the right humerus or any clockwise rotation of either forearms - watch his video between the 9:50 - 10:222 minute time points where he demonstrates his claim. How is that possible?
Here are capture images from that latest GG video that you posted.
Link to image if it does not appear -
perfectgolfswingreview.net/GankasSquat.jpgImage 1 is at a simulated P4 position and image 2 is at a simulated end of the hip-squaring phase.
Note that his clubshaft has shallowed between image 1 and image 2 without him "adducting his right arm + externally rotating his right humerus + supinating his right forearm". How is that possible?
It is possible because his body motions are atypical of what is seen in the early downswing of pro golfers - note that he is going from anterior pelvic tilt to posterior pelvis tilt that causes him to markedly decrease his spinal bend inclination angle and that causes his right shoulder to become much lower and become level with his left shoulder. Those biomechanical motions do not happen in the "real life" golf swings of pro golfers during their hip-squaring phase between P4 and P5.
Show me a video of a PGA tour golfer who does that type of artificial GG-squat move? I have never seen that phenomenon happen.
I will now analyse the pelvic motions of 5 famous PGA tour golfers to see whether they externally rotate their left femur a lot during their hip-squaring phase that happens between P4 => P5 (or P5.5).
Tiger Woods
Link to image if it does no appear -
perfectgolfswingreview.net/WoodsPelvicDepression.jpgImage 1 is at P4, image 2 is at P5 and image 3 is when his pelvis is square to the ball-target line.
I have drawn a red line along his pelvic crests at P4 (which is a good marker for hip joint height from the ground) and one can see that his right pelvic crest is slightly higher.
Note that both of his his pelvic crests get slightly lower during his hip-squaring phase, with no evidence of the left pelvic crest (left hip joint) getting much lower due to a lot of external rotation of his left femur in his left hip joint (note how little his left knee moves targewards between image 1 and image 2).
Note that the rightwards end of the green line (at his left pelvis) has moved targetwards relative to the rightwards end of the red line (at his left pelvis) and that reflects the amount of targetwards pelvic shift happening during his hip-squaring phase.
Sergio Garcia
Link to image if it does not appear -
perfectgolfswingreview.net/GarciaPelvicDepression.jpgImage 1 is at P4, and image 2 is at the end of his hip-squaring phase when his pelvis is square to the ball-target line.
I have drawn a red line along his pelvic crests at P4 (which is a good marker for hip joint height from the ground) and one can see that his right pelvic crest is slightly higher.
I have drawn a green line along his pelvic crest at the end of his hip-squaring phase - note that his left pelvic crest gets slightly lower in image 2 and that there is left-lateral pelvic shift happening. Note that there is only a small amount of targetwards motion of his left knee happening between image 1 and image 2.
Rory McIlroy
Link to image if it does not appear -
perfectgolfswingreview.net/McIlroyPelvicDepression.jpgImage 1 is at P4, and image 2 is at the end of his hip-squaring phase when his pelvis is square to the ball-target line.
I have drawn a red line along his pelvic crests at P4 (which is a good marker for hip joint height from the ground) and one can see that his right pelvic crest is slightly higher.
Note that both pelvic crests drop groundwards in image 2 by roughly the same amount because Rory increases his knee flexion bilatarally because he has an exaggerated squat move happening during his hip-squaring phase. Note that there is left-lateral pelvic shift happening during his hip-squaring phase. Note that there is negligible targetwards motion of his left knee happening during his hip-squaring phase due to external rotation of the left femur in the left hip joint (as recommended by GG).
Henrik Stenson
Link to image if it does not appear -
perfectgolfswingreview.net/StensonPelvicDepression.jpgImage 1 is at P4, and image 2 is at the end of his hip-squaring phase when his pelvis is square to the ball-target line.
I have drawn a red line along his pelvic crests at P4 (which is a good marker for hip joint height from the ground) and one can see that his right pelvic crest is slightly higher.
Note that his left pelvic crest actually becomes higher by the end of his hip-squaring phase due to the fact that there is no targetwards motion of his left knee happening during his hip-squaring phase due to external rotation of his left femur in his left hip joint (as recommended by GG) and due to the fact that his left hip joint becomes more vertically aligned over his left foot due to some targetwards pelvic shift happening with no significant change in his degree of left knee flexion happening at the same time.
Dustin Johnson
Link to image if it does not appear -
perfectgolfswingreview.net/JohnsonPelvicDepression.jpgImage 1 is at P4, and image 2 is at the end of his hip-squaring phase when his pelvis is square to the ball-target line.
I have drawn a red line along his pelvic crests at P4 (which is a good marker for hip joint height from the ground) and one can see that his right pelvic crest is slightly higher.
Note that both pelvic crests drop lower during his hip-squaring phase with the left side actually dropping less than the right side. Note that there is negligible targetwards motion of his left knee happening during his hip-squaring phase due to external rotation of the left femur, and that any targetwards shift of his left knee is due to left-lateral pelvic shift.
Jeff.