Whatever your sport (running, swimming, lifting, biking, etc) keep in mind form, but also remember to relax.
You’d be surprised how much energy you might be exerting in those tightened shoulders while you run or the constant flexed feet or overly tight grip. Ease up a bit by focusing on using your muscles, not tightening your entire body. I periodically will check myself especially when I am in the last leg of a long run. Don’t relax till you lose form, just be aware of what your body is doing and what it needs. Treat your body well and it will respond well.