[coophitter]

I'm a new contributor and an anatomy/physiology nut along with GSEM and PGA affiliation; I am compelled to clarify that wrists cannot rotate. They can only flex, extend, adduct, abduct, or circumduct from standard anatomical position. I have trouble understanding GM terminology. Only the whole arm or forearm can rotate. Forearm rotation is termed supination or pronation and whole arm rotation is termed either internal or external rotation or, in some circles, lateral or medial rotation. So is so called wrist rotation a form of forearm rotation or whole arm rotation. Mechanical advantage suggests that forearm rotation is great for opening jars and manipulating most faucets from hot to cold or on to off but not so great for manipulating a golf club. Whole arm rotation is much more massive, powerful, and precise than forearm rotation during a golf swing. Please explain or reply if my words provoke anyone.

Great to see you posting again, Mike

Lets clarify and be more precise about what a Swivel is.
A Swivel is a rotation of the Left Wrist from a Turned position to a Vertical position or from a Vertical position to a Turned position. The former is what we usually call “Standard Wrist Action on Downstroke”, or more commonly known as a “Release Swivel”. The latter is known as “Standard Wrist Action on Backstroke” or “Start Up Swivel".

What does “Turned” mean? Per 4-C-2, “When TURNED…the left palm faces directly toward that Plane."

Putting both these concepts together, this means the left palm is “Swiveled On Plane”, per my previous post.

So what the Start Up Swivel does is to put the Left Arm Flying Wedge On Plane, so it can remain On Plane until Release, just before the Release Swivel takes the Left Arm Flying Wedge (or the left palm) Off Plane to get into position to apply the selected Hinge Action.

With a Flat Left Wrist, the palm of the Left Hand must be On Plane for the Club to remain On Plane.

PS: photos can be deceiving!