"I'm sure you figure you snap your wrist on the serve on purpose and that pros do as well. But you may be confused by either of two pundits and their followers who tell you you're not figuring things out correctly here. One, Vic Braden, claims you and pros aren't snapping the wrist but only pronate the arm and hand; the other, John Yandell, says wrist movements are "passive," "not a causative factor" in power and spin, and that the wrist moves merely because it is "along for the ride" due to the movement of larger muscle groups or body parts. Both groups call the wrist snap "a myth."
This point of view is nothing short of ridiculous. Revolutionary Tennis says you're the one figuring things out right. And now clear scientific evidence disproving these pundits exists and can not be ignored.
TENNIS IS SIMPLE TO UNDERSTAND
THOUGH ADMITTEDLY HARD TO DO
item6A former teaching pro-now-Ph.D. candidate Brian Gordon in a series of articles researching "power" on a serve has published on the question whether the wrist moves voluntarily/consciously as a result of a muscle contraction on a serve ("wrist snap"), or whether the wrist moves involuntary because it is "along for the ride". This series of scientific articles ironically are showcased on Yandell's prominent web site which screams "the "wrist snap" "is a myth" in his article, "The Myth of The Wrist: The Serve." I stumbled onto Gordon's "The Serve and Tennis Science" by an email blast from the USPTA, I never would have found it trolling the site.
Is wrist movement a conscious thing, known as a muscle-driven joint torque, or is it involuntary, known as a motion-dependent torque because other body parts are moving? Pundits only claim the one, but Brian Gordon found both: He also found wrist movements to be conscious. What pros call a wrist snap is causative, active, purposeful."
I agree that it's conscious but it may well be that the end goal of wrist snap is what causes the arm to pronate. Pronating without wrist snap will give no power. Further, you don't see wrist snap because it is happening almost simultaneously with contact - you will see the wrist "broken" after contact though.