The biceps and triceps (both relatively small muscle groups) respond well to going heavy, and using more weight can provide a good-size foundation for the arms (and make them stronger) so your higher-rep sets can be done with even more weight, producing more mass.

The 5×5 training method is a lifting practice the late Reg Park (a three-time Mr. Universe and Arnold Schwarzenegger’s idol growing up) swore by in his prime during the 1950s and ’60s. Park used the first two sets of each exercise as a warmup, increasing weight from the first to the second set, building up to the final three working sets. On all three working sets, the weight stayed the same.

The following workout includes two exercises each for biceps and triceps, and you’ll alternate back and forth between the two muscles—as opposed to doing all biceps work, then all triceps work, or vice versa—to ensure that neither takes a backseat to the other.

5×5 Arm Workout

Excercise Sets Reps
Close-grip Bench Press (warmup) 2-3 8-12
Barbell Curl (warmup) 2-3 8-12
Close-grip Bench Press* 5 5
Barbell Curl (Straight Bar)* 5 5
Weighted Dips* 5 5
Seated Barbell Curl* 5 5

*Use the first two sets as increasingly heavier buildup sets, doing no more than five reps. Use the same weight on the last three sets.