I've always been under the impression that lots of jogging over time reduces your overall muscle mass. I can't remember if I learned this in P.E. or something, but it always seemed logical, less mass to carry means your body can go farther. Is that right, or just completely wrong? Thanks =)
I guess if you have a crappy diet, and you do exclusively jogging (ie no weight training or any other strength routines) then yeah, I can see you conceivably losing muscle mass.
