@kamilo12, thanks for the question. This is exactly what sport psychologists help athletes to do! Athletes can calm down before competition in a number of ways. Examples include using relaxation strategies (such as deep breathing), positive self-talk (i.e., speaking positively to yourself) and imagery (i.e., imagining being relaxed in your head and performing to your best). While it is generally good to be calm before competition, feeling nervous before an event is normal and as long as athletes recognize and see nerves as something positive, then that will lead to better performances.