Originally Posted by TheLambsheadrep
So there's pronation early before contact which relates to the racquet whipping around when you accelerate low-to-high to the ball. Is that pronation what causes the natural motion of the SSC aka the wrist turning over itself and finish "thumbs down" when you follow through across your body? Or is there another pronation just before/at contact that turns the wrist over and is mistaken for wrist action?
I wouldn't think of it that way.
Depending on the shot the pronation can occur before contact or after contact. There can be forearm pronation as well as pronation from the shoulder. There are several factors which come into play such as personal style and flair, grip, intent etc. There's also wrist ulnar and radial deviation.
SSC is something else and happens earlier in the swing and is not caused by pronation.