+1 to what everyone else said. Even the most isolated outposts have some sort of gym set up. FOBs will almost undoubtedly have treadmills/stationary bikes (though some are big/secure enough to go run outside). I don't know if you're going to Iraq or AFG, but if it's the latter, I wouldn't try to palletize or put a bike/trainer in a conex. The non sensitive-items stuff for units going in and out of country get shipped through Pakistan, and a lot of stuff never makes it. USPS is really efficient over there.