On going hard

A lot of the time when I run or play sports, I feel myself holding back, and I hate that. The reason I do it is because I am so afraid of pushing too hard and getting hurt again, and being sidelined from everything is one of the worst feelings in the world. It's really not worth it. I remember when I was younger, I would go harder than anyone else out there, and that's what defined me. Everything is different now, and I get that's how things go, but it still sucks. As we get older, we become more experienced and begin to learn. And yet, things don't really get any easier.