Fitness in the Field...

via Body Building.com...

by Dave Zyga, Captain, U.S.M.C. Mar 30, 2012

I hate to be the one to break it to you, but you're probably not going to get huge if your lifestyle includes sleeping in a different location every day.
The best you can reasonably hope for is maintaining what you have and bulking when you get a chance back at the FOB (Forward Operating Base).

Training - Muscle Gain

So, where's the gym around here? What, there isn't one? What do I do now?!
Make your own gym! You have to make adjustments to your training routine, but creativity can save you. Slow-tempo and plyometric bodyweight exercises may not be ideal for bulking, but can still offer enough stimulus to prevent catabolism for a few weeks.
When you're looking for something heavier or for different movements, there's no requirement that you must lift only a dumbbell or barbell.
If you have a vehicle or aircraft nearby, many have handholds, stowage bars, or horizontal surfaces you can grab. Use these for pull-ups (or partials) and bodyweight rows. If you're lucky enough to have a set of rings, a body suspension system or cargo straps, you can add bodyweight biceps curls, triceps extensions, bodyweight flyes and dips.
Resistance bands are a great investment! They're small, portable and accommodate an array of exercises to keep your sinew occupied.
A full 5-gallon water jug weighs approximately 45 pounds and has a convenient handle at the top. Too heavy? Drink a few gallons! Ammo cans full of sand weigh about 30 pounds. Use these for lateral raises, bent-over rows, biceps curls, overhead extensions, or for just about any exercise a kettlebell works for.
Boulders, logs and sandbags come in just about any weight you can imagine, both standard and metric. Biceps curls and overhead military presses are some obvious exercise choices, but don't limit yourself.

The good Captain pretty much covers all the bases so I recommend you read the entire article yourself.

No.

None of it is ground breaking stuff and its all pretty much standard Marine Corps wide.  Heck its pretty much standard Marine Corps AND Army wide.

But the best part of it is where he covers the nutritional aspects of things.  Unless you're at a big base, you're sucking down more MRE's than anyone could ever want...the key to that is to know what to keep, what to trade for and barring that...what to dispose of.

Oh and Body Building .com has some of the best prices on supplements on the net...Check his article out and the store...you won't be sorry.

SIDENOTE:

What I would like to know is if SOCOM does different workout routines while deployed than the conventional forces....hmmm.  Gotta find someone to ask...maybe Black Five has the skinny...

UPDATE:

Your body is an engine.  Stop putting bad gas in its tank...one month of clean eating will see you make more gains than over exercising ever will.  Fitness is 80% nutrition, 10% exercise and 10% rest/recovery.