Hugh Jackman knows what it takes to train to get big, and how to train to get lean. (Years in Hollywood starring in major films will do that for you.)

When Jackman needs to transform into an adamantium-clawed mutant, trainer Don Smith alternates between four weeks of heavy training and a few weeks of higher-volume workouts so Jackman can maximize size gains.

The heavy-lifting phase is done with low reps and long rest periods to train his body to recruit a maximal amount of muscle fibers. This in turn improves his performance during the volume phase, when he’ll use higher-rep sets and rest less time in-between them. He changes exercises slightly between phases—an incline press may go to a flat press, for example—and you should do the same.

Here's a look at how Jackman trains his upper body for Hollywood domination.

* The following workout is designed for training primarily for size. If training for strength, use the following rep, set, and rest scheme. Reps: 2-6; sets: 4-6; rest: 3-5 minutes.