Sasha,
My comment was a little hyperbolic, I admit, but according to the US Navy my lean body weight is somewhere around 152 lbs. I know I can stand to lose more than a few lbs of fat but if my math's right than I'd have to lose all of my fat and quite a bit of lean muscle mass to get anywhere near 140. Here's my question: If I were to lower my body weight to say 155-160 lbs and maintain all of my muscle mass so that I have a body fat % of 3-5% could I still achieve similar results as a 140 lb male runner that has an equivalent body fat %?
FWIW, I know a former D1 offensive lineman who weighed 3 bills in '03 when he graduated and got down to 210ish by '05. Granted he's 6'4", I'm only 5'10", but he's lugging around a lot more weight than me, I'm currently at 178. After 2 years of training he was already running sub 3:00 marathons and 1:25 halfs. Is he a freak of nature or is body fat % and fitness level more relevant toward predicting a certain level of performance? I'm desperately hoping the latter is the case.