Be careful with the hip flexor. You don't want to be all knotted up on game day. Limping during a routine is probably considered bad form. I remember going to a karate competition with a pulled groin muscle. It didn't work out to well. Happily I mostly got kicked in the stomach by small women and children so it didn't hurt very much but it's kind of tough to be graceful if you can't get your feet off the ground.