[Mike O]

In this model of a golfer, surely there are three axis points - i) the shoulders are rotating around the spine fulcrum point; ii) the left arm is rotating around the left shoulder socket fulcrum point; and iii) the clubshaft is rotating around the left hand/wrist fulcrum point.

As Matthew has correctly stated, the left shoulder point fulcrum point is moving upwards in the peri-impact zone and this moves the left hand/wrist fulcrum point upwards to an equal degree. While this is happening, the clubshaft is descending to the low point of its arc (relative to the left wrist/hand fulcrum point) and the low point depends on where the clubhead is in space at the time point of impact and the time point of the deepest divot depth (low point of the entire system). However, there is a third compounding factor - the movement of the spine fulcrum point upwards and rightwards as the golfer stands-up through impact. Surely, that must affect the low point of the entire three fulcrum point system because movement of the spine affects the position of the left shoulder?

Jeff.

Jeff,
Feel free to post but I'm waiting for Matthew to respond to my post and closing out our conversation. Surely, there are many other centers - and they may or may not affect the overall lowpoint of the system but I believe for now that Mathew and I are limiting the discussion to a "two center system" in order to understand the principle at hand.
Thanks