Feeling jittery before a race is normal, but staying sharp is key. One handy...
https://wiki-view.win/index.php/Breathing_Exercises_You_Can_Do_Without_Anyone_Noticing:_Quiet_Coping_for_Pre-Performance_Nerves
Feeling jittery before a race is normal, but staying sharp is key. One handy trick is to breathe in for four counts, then out slowly for six to eight—this helps calm the nerves