When you go to a tennis match, what exactly are you watching? Or, more precisely, how much tennis are you watching?

According to this article by Stu Woo of the Wall Street Journal, only about 17% of a match involves actual playing. The rest is taken up with toweling, arguing, bouncing balls, strolling, challenging, you name it.

And according to Woo, baseball (10%) and football (6%) have an even lower percentage of action.

All this down time gives the athletes plenty of time to think. That means how they think and what they think becomes vital to their success. Thinking can bring your mind to mistakes (past) and to worries about the outcome (future). Both these paths can get in the way of peak performance.

The more time between plays, the more skill you need in keeping more mind in the present. Whether you’re playing in the U.S. Open, the World Series or in a high school volleyball match, your mental game shapes the outcome.