I was thinking that olympic sprinter's carry a lot of muslce, with a very low bodyfat, which is obviously necessary to run as fast as they do. So I'm thinking, why am I, and others doing these 30+ minutes of boring cardio to lose body fat? (f.y.i, I don't take it easy on the bike, but I'm looking for a better way).
Maybe I should do short times of intense cardio,(sprints, high intensity on the bike, etc). How would I determine a training length? 10 minutes hard on the bike, etc?
Does anyone have any insight on how sprinter's train to keep their high muscle/low bodyfat level?

Raildog