If you were to look at some of the most effective muscle-and strength-building programs, you'll notice the total number of reps for the main exercises usually adds up to around 25. 

Take Mark Wahlberg's exclusive go-to arm workout, for example. This is the routine he uses to stay in tip-top shape whether he's starring in The Fighter or Ted. To make the most of your workouts and add slabs of muscle to your bi's and tri's, shoot for this number of reps—and your gains will add up too.

This workout offers two different approaches, listed here as Option A and Option B.

Workout Option A

How it works: Start heavy, end heavy

A moderate number of low-rep sets provides a blend of intensity and volume, which has always been associated with size and strength gains. Almost any combination will work: five sets of five, six sets of four, or eight sets of three all allow you to put some work in with big, challenging loads, and that’s as much math as any meathead should have to do in the gym.

Directions

The first time you perform the workout, you’ll hit 25 reps for the main lifts by completing five sets of five, as shown. If you repeat the workout, perform six sets of four reps. In the next session, do eight sets of three. Do not perform this workout more than twice a week, and allow at least three days before repeating it. On each lift that you use the 25-rep rule for, spend the first three or four sets warming up so that only the last two are done with heavy weights.

Workout Option B

How it works: Keep adding weight

The max effort method is probably the most powerful strength-building protocol available, and it’s a mainstay of powerlifters and football players. It’s also very simple to do: Keep adding weight to the bar until you reach the heaviest load you can handle for a given number of reps. After you max out your bench press, you’ll train the rest of the body heavy using exercises that help you to keep driving up your bench press and overall upper-body strength. As your strength increases, so will your muscle gains. And then we’ll revisit those forced reps.

Directions

Perform the paired exercises (marked “A” and “B”) as supersets. So you’ll do one set of A and then immediately do a set of B, rest, and repeat for the prescribed sets. For the remaining exercises, complete all sets for the move before going on to the next one.