Well, more and more athletes at all levels are applying lessons from the field of psychology to athletics.  The field of "sport psychology" has been growing rapidly for the last few decades.

Sport psychology has two main sides to it...

Assessing Mental States - On the one hand, it studies how thoughts and feelings affect how athletes perform, and how playing sports in-turn affects how people think and feel about themselves and others. 

Improving Performance - On the other hand, sport psychologists try to develop and teach specific mental techniques and skills that athletes can use to improve their performance, and that coaches can use to help their players play better.