It is basically sports psychology--being able to focus, staying calm under pressure, and sometimes being able to block out pain while performing.
Here is a link to a basic overview on it relating to gymnastics. In my personal opinion, I think that the concept is geared more towards teenagers and adults. I'm not too certain if young kids even have to worry about this at such a young age. But...I could be totally wrong. If someone has more experience with this subject, please chime in!!!
MdGymMom hit the nail right on the head...its basically talk therapy for athletes. I've found it somewhat helpful. Basically they try to get us to put fears aside and concentrate on the important stuff like winning a game, scoring a goal, or nailing a perfect floor routine