a coach's advice

Avoid using, wearing, or eating anything on a race day that you haven't tried in practice. You never know whether that new mango-flavored gel will disagree with you midway through the race or whether going barefoot in the new long jump spikes will cause blisters, and you don't want to find out during a competition. Maybe everything will be fine, but why take a chance? Test snacks, equipment, socks, and shoes in practice first. You don't need anything else to be nervous about.