The importance of early preparation in tennis and other sports has been well-documented.
Nick Bollettieri, the well known tennis coach, in one of his books describes a rating system that he used to evaluate the level of various tennis players.
An average player gets ready or prepared as the ball bounces on his or her side.
A good player gets ready or prepared as the ball comes over the net.
A better player gets ready or prepared as their opponent hits the ball.
A top player gets ready or prepared before their opponent makes contact with the ball.