Or you could just...stick yourself out for physical labour. I don't mean go to the gym, or the hell of [i]jogging long distances in nylon crap.[/i] Building large muscles just requires you to add another routine to keep them there, if you don't use them often for any reason. I can't really give a generic guide, but I'll just have to use myself as an example. I carry logs. Piles of them, or big heavy ones. I cycle or walk to the nearest town (about a mile away) when I visit friends, do stuff with them, go to school, whatever. Doesn't seem like much but if you do it often you can notice a difference, and it doesn't really require too much of a change. It doesn't make you a Hercules if that's your plan, but it certainly keeps you in shape. Just think of your normal routine, and make a minor effort to make it require a bit more elbow grease. It doesn't suit everyone's lifestyle, but neither does rigorous exercise regimen for much of us anyway.