Originally Posted by sureshs
No, you got it wrong as usual.
Vic's analysis (with his colleague) is here. The speed goes from 7 (top of swing) to 25 (lowest point of swing) to 71 near impact (in that analysis, contact was in front of the chest).
Did you really think Federer would swing at 17 mph at impact? I think even casual tennis and golf players know that the number is way too small.
It is possible that Wegner is discussing some other forehand, but I think that the video of the fh shown is fairly typical. As you correctly note, the racket goes from roughly 25mph at the end of the racket drop (sometimes called the 'pat-the-dog' position) to 71mph at contact. That's an acceleration of about 46mph into the forward swing.
So it is clear that the most of the pros, when hitting a hard ball, are accelerating hard out of the racket drop. They are not waiting to accelerate until almost at impact.
A question for Wegner: Do you really believe that players are waiting until the hand is almost at contact to accelerate, or is this a teaching trick to encourage players to accelerate harder with a short backswing?
The ATP players have shorter backswings (Soderling is an exception) than most of the WTA players who will have a more gradual acceleration profile. That short backswing suggest the acceleration out of the drop is going to be pretty impressive. (I could be wrong about the acceleration pattern differences, I probably should look for data when comparing ATP and WTA.)