Not your average workout: Tire flipping, jumping, sprints with a jumpstretch band, runs with kettlebells, turkish get ups with kettlebells, medicine ball throwing, kipping pullups, bear crawls, tuck sits on gymnastics rings, barbell thrusters. Real, oldschool, brutal - full body movements.
You'll notice they aren't doing any curls or tricep extensions, no machines, no pussy bodybuilding "watch yourself in the mirror exercises" crap. It takes real world strength to flip tires and do pullups and squats and sprints. Essentially, the actors were training for performance - and the look came with it.
http://joshsgarage.typepad.com/articles/2006/11/frank_miller_mo.html
