Focus in tennis

This article reviews "focus" in tennis, but I believe it can be applied to any discipline.

http://www.tennisserver.com/turbo/turbo_06_10.html

The author states that focus, let me say concentration, is something that can and must be trainned during trainning sessions. Also, that rituals play a crucial role on focusing, as most of the players do when they bounce the ball exactly the same number of times before serving, or when they walk away and come back to the same point between points.

Anyway, I found it interesting, so here it goes.

P.D. It also talks that you cannot be 24 hours a tennis player, that you must switch on and off. This I believe also applies for engineering, don't you think so?