how about this example,
Originally Posted by toly
Let’s assume that ball travels from opponent’s racquet to your point of contact Ttr seconds and your back and forward swing takes Tsw (can be about 0.5sec). Thus you should start backward swing after Ttr-Tsw when the ball lives the opponent racket. That’s why there is practically no correlation between timing of your swing and ball’s bounce.
To illustrate this idea there is Safin difficult FH from baseline http://youtu.be/PvkLy7vZyy4
. He almost finishes his forward swing before ball’s bounce.
Somewhat confusing ...