Originally Posted by JohnYandell
Most of the debate over technique centers on the fundamental stroke of the forehand.
Let's start with some basic facts. In the pro game in a typical groundstroke exchange, there is about 1 second between the rackets. The ball leaves Fed's racket and 1 second later it leaves Nadal's, plus or minus.
As our research was the first to show, the ball loses about 50 percent or more of it's speed in this interval. If that wasn't true the speed of tennis would exceed human reaction capacity.
So on a forehand measured off the racket at 80mph, pros are actually hitting an incoming ball that is, say, traveling around 40mph, and they have at most a few tenths of second after the bounce in which to make contact.
But speed and time are not the only factors to consider in the nature of pro excahnges. The balls are leaving the racket on the top forehands with 2500rpm of spin or more. And the spin actually increases after the bounce. The bottom half of the ball grabs the court and the friction causes the top half to accelerate. After the bounce the spin can double. We've measured balls spinning at over 5000rpm before the contact.
So between the hits, the speed is halved and the spin is doubled. What does it all mean?
I think it means the ball is freakin moving fast... The focus of a player at that level is to be able to still the mind and be able to slow down the perceived speed of the game. Every tennis player has felt this, when your mind is calm and you see the fastest balls slow and huge. Your sense of time is slowed. Its the zone. Every athlete has felt this.