I am not a teacher, but common sense tells me the swing starts simultaneously. If anyone trys to build into their swing the concept that the swing starts in the leggs and makes a conscious effort to start it from the legs they are doomed. There are many things happening at the same time, "SIMULTANEOUSLY."
One thig I have noticed on theis forum is that the movement of conversation is conventonal in nature.
There is a Paralysis by Analysis in the on going saga of many folk on this board - a fundamental departure form NG and a true SA method of golf.
Conventional Golf has this problem, "Paralysis by Analysis."
