According to Bas, lots of muscles require lots of oxygen, which is why some of the body builder types gas out. Josh Burkman and Phil Baroni, two guys who must have less than 10 percent body fat, are examples of lean, muscular guys who always seem to gas out. And then you have guys like Fedor and Karo, both of whom look kind of soft, but seem to be able to go full bore all day long. Any scientific data that relates stamina to body fat? Is it better to be ripped or to have some fat reserves to draw on?