Sharing the grueling exercise regimen with Men’s Health, celebrity trainer Jason Walsh, who’s worked with other stars like Matt Damon, Miles Teller, Brie Larson, and Bradley Cooper, said that the program had Jake Gyllenhaal’s role and what he’d need to bring to the set in mind. It followed a progressive structure that involved conditioning, building muscle, and MMA sport-specific movements.
There were mobility drills, Proteus motion machine workouts, isometrics, heavy sled exercises, safety bar squats, forearm drills, offset loaded bag drills, floor presses, chain pushups, suspension trainer push-pull movements, push-pull rips, and climber sprints. Mobility drills are great for increasing range of motion, while the Proteus motion machine helped warm up the “Southpaw” actor’s joints, per Walsh. “The Proteus is an amazing piece of equipment used mostly by professional performance centers to help train athletes in every plane of motion and also to increase power production,” explained Walsh (via Men’s Health). At Rise Movement, the Los Angeles, California-based fitness center co-founded by Walsh, the machine is mainly used for priming the nervous system, learning movement patterns, warming up joints, and metabolic training, added the trainer.
Isometrics, exercises that focus on contracting specific muscle groups to maintain and build strength, were next on the list of Gyllenhaal’s workout routine. Isometric inverted row holds were one of the exercises the actor did, aimed at boosting “strength and stamina at different joint angles,” shared Walsh. There are actually three different types of muscle contraction workouts — isometric, isotonic, and isokinetic exercises.