Originally Posted by toly
In video http://www.youtube.com/watch?v=mM1P2ej4YtY
Alejandro Falla, 29 years old pro from Columbia, looks like followed your advice, but failed to learn how to recognize direction of the ball bounce. IMO, he first must learn this stuff theoretically, then go to court and destroy Federer serve.
Federer hit an ace. as simple as that. he does that even against people like Djokovic. there is nothing you can learn theoretically, sorry