I remember playing some speed chess with someone my level (I'm not an experienced chess player). It's a really different experience from the regular long-contemplation chess. What really stood out to me was how dramatic the effect of deep deliberate breathing was. My ability to make quick and good decisions would improve immediately. Similarly in tennis (I've played like 3 times), or badminton, concentrating on the ball would have a huge effect on being able to return it well.