The CompuSport CD, “MODEL GOLF – Swing Like A Pro”, by Dr Ralph Mann, a biomechanics expert, has detailed instruction about the transition move. The lateral hip slid should start well before the shoulders have fully turned in the backswing.
There is just one small problem. The associated animated computer model - “The Pro” - based on over 100 pro swings of both PGA and LPGA players, does not show this at all.
Instead if you will see first a motion of the upper body resembling that of a tree gently toppling towards the target before the lower body gets into the act.
I have seen this before in golf swings and viewing Brian’s lagpressuredrill.mov video I also noticed exactly this same motion. The very first move appears an upper body move gently topping over to the target.
It is an interesting example of discrepancy between what is being taught and what is actually taking place.