[Jeff]

12PB You wrote-: "To hit the ball far . . . you extend from the feet up . . . each segment . . . . probably the biggest segment (really bunch of little segments) is the spine . . . . people who hit it really really long EXTEND/stretch out their spine . ."

I agree that long drive competitors need to brace their spine and left leg for maximum stability and I think that goal is best achieved when the spine is straight (extended) and the left leg is straight (extended), and the spine is angled back slightly so that the skeletal axis from the head to the left foot is optimised for power and balance.

Your photos demonstrate that even Jason has considerable secondary axis tilt at impact.

Jeff.