52 - The Serve - From hi-techtennis.com - Lesson 5: Pronation - Pronation Visualized

Lesson 5: Pronation - Pronation Visualized

I would like to look at "pronation" much more closely. It is the key to a big serve, and it is the heart of a big overhead as well, so I think it will be very worthwhile to explore pronation in depth.

There is a very specific sequence of events that occurs just before impact. First, you can see how the racket and forearm are at a 90 degree angle in the first frame. This comes from "pulling" the racket, butt cap first, upward. In this first frame, the wrist is laid back, causing the racket to be in the "Big L" position.

Now the wrist will "catch up" to the forearm by whipping forward and turning (rotating) into the ball. On impact, the wrist will remain stable (it has caught up to the rest of the forearm) and the entire arm will turn outward.

Federer's technique is identical to Johannson's. The racket twists into contact and then the entire arm turns outward after impact. Notice the long extension of the arm and racket towards the net.

Here you can see how Johannson's racket face completely reverses direction from the first frame to the third frame. On contact, his racket is half way through this 180 degree twist. The serve (and overhead) gets tremendous power from this torquing motion which we refer to as "pronation".