It really depends on the sport, and what you consider a sport. For things such is Football, or Rugby can often lead to concussions more often than other sports, like soccer or bowling even. But you're running quite a bit in most sports, even in things like tennis. So I would say an increased lung capacity, and building more leg muscle. However if you're bowling, you'll gain more arm strength, but you could also hurt your back if you throw the ball wrong. I mean the question is almost too broad to cover by just me.
