Brad Bose, PhD, the man in charge of training Robert Downey, Jr. for Iron Man, Sherlock Holmes, and Iron Man 2 put him on a “functional fitness” regimen that included all sorts of unorthodox exercises and routines.
Functional fitness is an approach to fitness that utilizes REAL LIFE ranges of motion instead of repetitive, robotic machine motions (like body building). There is less focus on isolating individual muscles and more focus on working out the entire body. The end result is a lean, muscly body that performs at it’s peak across a wide range of activities (not just lifting). The result of traditional body building and “cardio” exercising is peak performance (if you can even call it that) in one or two activities (lifting, flexing, or running on a treadmill).
They had just 3 months to get Downey into Tony Stark form after he had dropped 20 lbs to play Sherlock Holmes.
His workouts included exercises and techniques such as Indian Clubs, Meels, Wheelbarrows, Fire Hoses, Sled, Giant Tires, Sledgehammers, and more unorthodox workout routines.
Downey was tired of the regular routine of hitting the gym and just lifting weights and said, “If I have to get underneath a bench press or [do] a squat, I’m going to shoot myself. I just don’t have the motivation.” So, Bose put him on this functional fitness regimen that really “shock and awed” his body.

If you want proof that there’s something to working out out in a non-traditional, non-body building way just take a look at Robert Downey, Jr. in Iron Man 2. He built that physique in 3 months using functional fitness workouts.
For more information and the details of each workout element see the full article at WebMD.