For the majority of guys going to the gym, the ultimate goal is to build muscle—on top of shedding those unwanted pounds, of course. But what is the perfect number of sets to maximize muscle growth? A recent study on Brazilian Navy cadets offers new insight.

For six months, a group of Brazilian Navy cadets took a break from regular boot camp workouts to conduct a weight-training experiment—doing either one, three, or five sets per exercise, and tracking strength gains.

The results? The five-setters earned significantly more muscle mass than the other two groups, and upped their five-rep max more as well, according to a study published in the Journal of Strength and Conditioning Research.

The findings back the “five sets/five reps” model that trainer Don Saladino, co-owner of NYC’s Drive495 gym, uses for big lifts like the bench press and squat.

But for unilateral movements like side-lunges and one-legged squats, do just two to three sets to promote athleticism, he says: “You aren’t doing it to build muscle mass.” For more tips on forging lean mass, check out these 10 ways to bulk up your entire body and the 15 most basic facts about building muscle.