You wrote-: "Jeff . . . Why should we pivot like that?"
Because there is no other way. What I mean is that if a human being does nothing more than rotate the pelvis 45 degrees by moving the right femoral head backwards/leftwards, and he lets his body/head move naturally/passively in an unrestricted manner, then he will end up with a reverse K posture. BM is exaggerating the upper body rightwards tilt motion.
In a human golfer, who consciously decides to keep his head stationary during the 45 degrees pelvic rotation movement, the natural movement of the upper torso becomes restricted and that is why the mid-upper thoracic spine becomes verticalized (when it would normally continue to spiral rightwards in a natural spiral arc).
You wrote-: "Jeff . . . Why should we pivot like that?"
Because there is no other way. What I mean is that if a human being does nothing more than rotate the pelvis 45 degrees by moving the right femoral head backwards/leftwards, and he lets his body/head move naturally/passively in an unrestricted manner, then he will end up with a reverse K posture. BM is exaggerating the upper body rightwards tilt motion.
In a human golfer, who consciously decides to keep his head stationary during the 45 degrees pelvic rotation movement, the natural movement of the upper torso becomes restricted and that is why the mid-upper thoracic spine becomes verticalized (when it would normally continue to spiral rightwards in a natural spiral arc).
Jeff.
Jeff,
Couple of questions would like to ask...
Is there any way to have a "look" of 45 degrees hip turn that did not come from rotation?
If you practice your quoted "drill", did you hit fat?
__________________
If you cannot take the shoulder down the clubshaft plane, you must take along some other path and add compensations - now, instead of one motion to remember, you wind up with at least two!
If the pelvis is square to the ball-target line at address, and then 45 degrees angled to the ball-target line at the end of the backswing, then it has rotated 45 degrees. How it got to that 45 degree rotated position could vary from a biomechanical mechanism perspective. For example, in my diagram I show how the right femoral head has moved backwards and leftwards. That could occur via different biomechanical mechanisms. One could use pelvic girdle muscles to pull the right pelvis back and secondarily the right femoral head back (because of its snug-relationship to the hip socket joint). Alternatively, one could shift the torso right-laterally against the resistance of a "fixed" right knee => that causes the deflected forces to slant the right thigh to the left => that drives the right femoral head left-backwards => then the pelvis moves secondarily to the movement of the right femoral head.
I only tried the drill once to understand the biomechanics. I think that BM was using that drill to teach golfers not to sway the pelvis laterally, but to rotate the pelvis.
Brady Riggs is teaching the same basic principle is this swing video lesson.
You wrote-: "And what's the problem with "the natural movement of the upper torso becoming restricted and that is why the mid-upper thoracic spine becomes verticalized (when it would normally continue to spiral rightwards in a natural spiral arc)." Sounds like the way it should work to me."
I agree. I stated the same thing in the previous post. It is a good idea to keep the head stationary.
That is my photo of Snead. It is interesting because Snead turned his pelvis more then 45 degrees (? 70 degrees). That causes the lower lumbar vertebra to move so far leftwards that the front of the lumbar spine will almost be facing away from the target. With the addition of an erect posture, one could then rotate the upper torso around a near-vertical spine. Then, one would not end up with a reverse K posture - like Hogan. In fact, Snead has a small degree of reverse pivoting. The reason is that he has a near-vertical spine, and then the addition of a >100 degree shoulder turn torques his upper thoracic spine even more left-of-vertical.
If the pelvis is square to the ball-target line at address, and then 45 degrees angled to the ball-target line at the end of the backswing, then it has rotated 45 degrees. How it got to that 45 degree rotated position could vary from a biomechanical mechanism perspective. For example, in my diagram I show how the right femoral head has moved backwards and leftwards. That could occur via different biomechanical mechanisms. One could use pelvic girdle muscles to pull the right pelvis back and secondarily the right femoral head back (because of its snug-relationship to the hip socket joint). Alternatively, one could shift the torso right-laterally against the resistance of a "fixed" right knee => that causes the deflected forces to slant the right thigh to the left => that drives the right femoral head left-backwards => then the pelvis moves secondarily to the movement of the right femoral head.
I only tried the drill once to understand the biomechanics. I think that BM was using that drill to teach golfers not to sway the pelvis laterally, but to rotate the pelvis.
Brady Riggs is teaching the same basic principle is this swing video lesson.
Jeff.
Jeff,
I am seeing it a little differently. I am seeing Mr. Manzella creating some tilt by moving his head and shoulders back over the right foot. I am seeing Mr. Riggs create some tilt by moving his hips forward while keeping his head more stationary. Mr. Riggs motion reminds me a lot of VJ Trolio's Hogan "secret" move. I really like that motion.
What am I missing?
Kevin
__________________
I could be wrong. I have been before, and will be again.
I think that BM and BR are performing the same pelvic rotational movement from a biomechanical perspective, except that BM is deliberately allowing his head and upper torso to rotate as far as possible to the right (head is outside his inner right foot) to exaggerate the drill effect and to get that clubshaft perpendicular to the ball-target line. By contrast, BR is probably attempting to keep his head more stationary and within the boundaries of his stance.
Most folks see movements of the whole spine differently or similarly depending on what it is that they agree upon to see. There are three academically agreed upon sections of the spine that can manoeuver independently from each other or in concert with each other. If any or all of these sections pivot from a starting condition then there can be no sway (or bob). Each section can likewise sidebend, flex, or extend in concert or independently. The lumbar joints are typically less flexible and offer less range of motion than the thoracic joints, and thoracics likewise are less flexible and mobile compared to cervicals. Things get mighty complicated when the three sections are connected and thereby influenced by movements of scapulas, shoulders with humeral heads, pelvises with femoral heads, etc.
Regardless of the inherent complexity of observed spinal movements, if any section of the spine pivots from an original vertical, sidebent, flexed, or extended condition, then that section will retain its original condition. Otherwise the section or sections in question did not pivot. Most golfers start with a bit of sidebend away from the target with all three sections of the spine. If they truly pivot then the original sidebends are retained.
Perhaps "pivot" needs to be redefined for golf swing observations and resultant commentary. Perhaps golf swing observations and commentary concerning pivots are intrinsically too difficult for the human eye to accurately perceive because in the pivoting of any object with girth, the frontal view of a point on that object will move in the opposite direction of a point 180 degrees away on the backside of the same pivoting object.
If all agree that any segment of the spine is tilted or sidebent away from the target at address then all must agree that that segment will remain in that tilt or sidebend if it truly pivots thereafter, even though it may not look like it is truly pivoting from a different point of view. Otherwise we need to call segmental movements of the spine during the golfswing something else as we tend to do when we observe that at least a portion of the spine sidebends a bit more away from the target(secondary axis tilt) to facilitate a good downswing.
By the way, I'm probably like most experienced video teaching pros in that I have never witnessed what I could honestly diagnose as a pure backswing or downswing pivoting of the segments of a given spine in any given swing I have ever analyzed.