Sports psyche: Crying when injured

In the past year, I’ve seen two kids I really care about break down in tears when they get injured during a game. In each instance the injury turned out to be minor, and they were able to return to the court after sitting for some minutes. But it was pretty scary for a little bit.

Being heavily into sports psychology, this got me wondering why some kids cry in injury and some don’t. I’m not finding anything online that’s helpful at all. But I theorize that those who get upset are usually the kids who tend to take things personally and/or have lower self-confidence and/or self-esteem. I’m interested in what others have read or studied, though.

Why do some kids get upset in the face of an injury?