In the upper body days, they used to do a combination of pushing and pulling exercises to cover the chest, back, shoulders. fishesand triceps in each session. They also varied between horizontal and vertical movements from one workout to the next, allowing them to work the muscles at different levels of motion. “We’d do a flat dumbbell bench press, and then the next upper body day we’d do it on an incline,” recalls Stump. “Or if we did a chest-supported row one day, we’ll do pull-ups the next.”
Sessions would begin with the main lifts, such as the bench press or row, followed by accessory work, such as cable flyes or landmine presses, to isolate the smaller (albeit highly photogenic) muscles that would receive the most screen time in the film. Stump told Damon to perform three or four sets per exercise across the board, consisting of 8 to 10 reps for the main lifts and 12 to 15 repetitions for the subsequent accessory work. “The general idea was to do more volume,” says Stump. “A lot of sets, versus really intense strength work.”
The same formula was followed for the lower body days as well. “We had a trap bar, so our big leg lift was a trap bar deadlift,” says Stump. “That’s where we’ll go the most.” But in the absence of basic leg-day equipment, like a squat rack, the two had to get creative. “We had a regular barbell, but no rack,” says Stump, “so we did landmine (squat) variations, and a variety of hip thrust“
Stump believes the cardiometabolic day was less structured, noting that Damon is not particularly fond of cardio. (“She hates doing cardio. But who doesn’t, right?”) Instead, these sessions served as a miscellaneous catch-all for any kind of beneficial non-strength work. Some weeks that means intervals on the Versaclimber or a HIIT circuit that includes medicine ball slams, kettlebell swings and jumping rope, while other weeks the pair will focus solely on mobility or steady-state cardio. “Let’s say we did some tough workouts during the week and we needed something that was less intense,” says Stump. “So I’d just say, ‘Okay, throw it weight vestPut on your headphones and walk upstairs for 45 minutes. It doesn’t have to be very strong; Just sweat a lot and then come home.”
“The power of a sacrifice lies in the worth of the one who makes it.”
At the end of the day, no matter how hard he worked or how often he worked out, Damon’s ability to lose 15 pounds of fat would come down to his diet. “I told them early on that this was a diet and nutrition goal,” says Stump. “Whenever you’re talking about losing body fat, it’s a calorie thing. You’re not going to be able to control that by exercising more.”
Luckily, this was no surprise to Damon, who knows his way around Hollywood change. “My big thing was just to make sure he was getting enough protein to support the muscles, but the truth is he didn’t really need that much help with his diet, and I think that’s because he’d done it so many times before,” says Stump, who notes that staying away from alcohol, gluten, and processed sugar helped Damon significantly cut his calorie intake while training for the role.
According to Stump, it was ultimately Damon’s commitment to the process – both in the gym and on his diet – that allowed the actor to achieve blockbuster results in such a short time. “In terms of his training, I would say the most impressive thing about him is his consistency,” says Stump. “He’s really a guy who will show up day in and day out and put in the work. And I think that probably comes through the most in terms of the way he looks in the movie.”
A version of this story originally appeared British GQ.
