|
Post by imperfectgolfer on Aug 12, 2012 7:05:35 GMT -5
Consider this BM-forum thread www.brianmanzella.com/golfing-discussions/17556-foley-says-kostis-mangled-tiger-swing-analysis-8.htmlBM stated-: " The pivot is leading the hands and club into impact.
But it is in MASSIVE deceleration before impact.
Trying to just pivot with no decel through the ball is total junk—if you actually do it." Wulsy agreed with BM when he stated-: " I just can't believe that there are still guys out there who think the opposite. They must be gaga." Where is the "evidence" that Hogan or John Erickson are massively decelerating their pivot motion before impact? Jeff.
|
|
|
Post by gmbtempe on Aug 12, 2012 13:03:07 GMT -5
What do some of the 3d graphs show?
|
|
|
Post by imperfectgolfer on Aug 12, 2012 18:37:36 GMT -5
Any graphs that I have seen have only measured golfers who decelerate their pivot action prior to impact. I have never seen torso rotational velocity measurements (or graphs) on golfers who pivot actively through impact - like John Erickson.
Jeff.
|
|
|
Post by imperfectgolfer on Aug 12, 2012 19:09:31 GMT -5
BM wrote-: "The hips turn less than the chest on the backswing, the chest less then the left shoulder complex, the left shoulder less than the hands, the hands less than the club.
Early in the downswing, the hips lead the chest, which lead the left shoulder, arms, hands, and clubhead.
If they all continued through impact at the same rate, you'd have a great big mess.
Why?
Because there would be no way to put the clubhead speed needed into the club. (plus a whole bunch of club delivery issues)"
That's BS!
The pelvis, upper torso, arms and club are all moving in different planes around different axes. In particular, the left arm mainly moves downwards and forwards towards impact when PA#4 releases, and there is very little outward motion (which is a measure of its rotational speed relative to the spinal axis of the upper torso). Therefore the left arm can move at a greater linear speed than the upper torso, but that doesn't mean that it is rotating around a central axis at a faster rotational velocity than the upper torso's rotational velocity. Secondly, the purpose of continued active pivot rotation between P7 and P9 has nothing to do with power generation, and it primarily allows a golfer to keep the arms/club in front of the rotating body if the golfer uses a CP-arm release action. If the golfer didn't rotate the upper torso and arms at the same rotational speed (not linear speed) during a CP-arm release action, then how could he efficiently keep the arms continuously in front of the rotating torso?
BM also wrote-: "Intention—to get the club to and though the ball—is the key.
Often, this intention is sub-conscious, but the application of the clubhead to the ball, through the hands, is what sets in motion all the accels and decels."
I bold-highlighted a BM-claim. How is that possible? I think that he has cause-and-effect reversed.
Jared wrote-: "If everything moved at the same rate, there would be no release. At some point the hands, arms and club have to release independent of the body".
That's a typical over-simplistic BM-groupie comment. They think so simplistically. The release of PA#4 and PA#2 are happening in a specific plane that has nothing to do with the plane of torso rotation. Imagine a rotating body rotating in space around the earth's equator (from east to west) at the same rotational speed of motion (relative to a central axis that goes from the north pole to the south pole) as the earth's rotational speed of motion. If during its rotational motion, it also moves northwards-and-then-southwards in a continuous sine-wave manner, then it has much greater linear speed along its sine wave path than the earth has along its rotational path, but it still has the same rotational speed as the earth (relative to a central axis that goes from the north pole to the south pole).
Jeff.
|
|
|
Post by imperfectgolfer on Aug 12, 2012 19:32:30 GMT -5
Ringer wrote in the BM-froum thread.
"It's simple.
Kinetic chain.
One muscle group helps to propel the next muscle group, which then helps propel the next muscle group.
If the first muscle group is trying to continue propelling all the way through impact, then only one set of muscles are actually doing any work. Seems rather silly."
He thinks that it is simple, but I think that he is being simple-minded (silly). The muscles activating the movement of the pelvis, and the muscles moving the upper torso and the left shoulder girdle muscles moving the left arm are not operating in the same rotational plane. There is obviously some passive contribution from the muscles that actively move the pelvis to the movement of the upper torso because the pelvis is connected to the upper torso via the spinal column and the torso's soft tissue structures (muscles and ligaments). There is also some passive contribution from the muscles that rotate the upper torso to the left arm's motion because the left arm is connected to the upper torso via the left shoulder socket joint, but PA#4 release is mainly downwards between P5.5 and P7 and its speed of motion is also affected by the active contraction of left shoulder girdle muscles. There must be a "correct" kinetic sequence of muscular contraction, but it doesn't operate like a kinetic chain.
Jeff.
|
|
|
Post by tomdavis76 on Aug 13, 2012 19:00:08 GMT -5
As the arms and club extend during the release phase, the arms/club moment of inertia increases. Unless the golfer at this late stage increases his rotational torque, things will start slowing down on their own.
That said, it doesn't look like Hogan ever slows the hips down until he runs out of range-of-motion:
|
|
|
Post by imperfectgolfer on Aug 13, 2012 21:06:34 GMT -5
Jeffy wrote-: "That said, it doesn't look like Hogan ever slows the hips down until he runs out of range-of-motion."
Hogan also doesn't slow down his upper torso rotation, and the left arm is attached to the upper torso via the left shoulder socket.
Jeff.
|
|