To prepare for filming, MacPherson focused on adding size to his shoulders, chest, and back to get “really thick” to emulate the look of the special operations soldiers and Navy SEALs he met while doing research. By employing fasted cardio, high-intensity workouts, and eccentric exercises—as well as a high-protein diet—MacPherson built an imposing physique and the strength to easily carry 30-40lbs of equipment.
Following those months of preparation, the actor and his castmates—including former pro-fighter-turned-actor Warren Brown (Sergeant Thomas "Mac" McAllister), Roxanne McKee (Captain Natalie Reynolds), and Alin Sumarwata (Lance Corporal Gracie Novin)—continued to keep an intense daily workout routine to maintain their gains.
“I was the heaviest I've ever been in my life,” MacPherson told Men’s Fitness. “Then, when we were shooting, we’d work until about 7 p.m. at night, get in a pre-workout meal, and go hit the gym for two hours. We also had weights on the set, so if you had a scene off or a moment off, you could at least just go and do a set of something, just to keep it moving. The physical transformations from Alin and Roxanne were incredible as well.”
While that daily routine was pretty intense, MacPherson saved his best for last. In what the actor calls his “Sunday Special,” or the “Sunday Fun Day” routine, MacPherson led the group in a circuit training routine that would “burn everyone for a couple of days”.
“I made it so we could scale up to whatever we needed,” MacPherson said. “During the week, we’d do maybe seven exercises. On Sunday we went to 10 exercises, 10 reps, for 10 rounds and worked down the rep ladder from 10 to 1 as we went. We’d mix in deadlifts, plyo pushups, kettlebell swings, pullups, chinups, maybe a biceps curl sometimes, or burpees, and that would hit all of our muscle groups. As you go down, we added weight, so you're getting super-heavy as you go. It’s a beautiful workout that was a bang for your buck. It helped us hit all of the aesthetics that we needed, as well as burning a ton of calories, which would give us a boost through the week.”
MacPherson started with an 8-minute rowing warmup, progressing from medium-to-hard-to-harder every 2 minutes. After the warmup, MacPherson jumped into the 10-move, 10-round workout.
In the first round, do 10 reps of every exercise. Do one fewer rep in each subsequent round (9, then 8, then 7, etc.) until you finish 10 rounds. We've labeled that below as "10–1".
MacPherson added weight to the barbells every second round. By the last round, he'd lift close to 80% of his one-rep maximum. Experiment with the weight increases, and make sure you're doing reasonable weights for yourself.