Holy shit... I read that article and am in awe...
As it says, sprints can simultaneously burn fat, and maintain muscle mass and strength! In fact, builds mass in the legs...
That said, why doesn't anyone seem to realize that's the anwser? Even me now, I don't even have to gain weight! With sprints I can now eat alot, put on minimal, if any fat, and get more mass in my legs as well! And increase lung capacity? Come on people, you all better fuckin' start sprinting or this high, buzzed, itchy, raging adolescent will have to assassinate you!