A wrist question on a spin serve...

[gzhpcu]

John,
I just read a new take on the wrist movement on the serve, and was wondering what your thoughts were. Basically what is being said is that at the moment of impact, there is a "wrist snap" (wince...), but here they define it as not that the wrist bends forward but rather moves from left to right (ulnar deviation), and this must be done intentionally.
So they say, the wrist comes up from the flexed to neutral position at impact, plus there is an intentional left to right wrist action (ulnar deviation).

[johnyandell]

I think that this is again a result of other forces. I definitely can see it in the high speed footage--on some serves--ie, wide in the deuce court for righthanders.

If the wrist is loose it's the natural consequence of the speed and direction of the racket.