How to Train a Muscle's Fiber Makeup for Maximum Size

Q: I am a newbie to bodybuilding. How heavy should I go on shoulder exercises to get a full workout? I am already in good shape from athletics.

- Ian E.


My Answer: If you're going to be a bodybuilder, then what you'll need to do is focus on "size training" as opposed to athletic training.  Depending on the sport your athletic background should have helped developed the strength, explosive and endurance of your deltoids.

Each muscle group has a "personality" based on its fiber makeup.  This means that the deltoids respond to a specific range of repetitions and a specific tempo.  In fact the 3 deltoid heads differ from each other in terms of rep ranges.

The anterior delts are comprised of primarily fast-twitch muscle fiber, so they respond best to low reps and extremely heavy weight.  If you look at weightlifters, they have well developed delts from explosive overhead lifts like the clean and jerk.

The lateral (sometimes called medial) delts are comprised of strength endurance fibers, so they respond best to high reps.  This is why basketball players have full but ripped delts, because they're constantly raising their arms overhead.

I go over these differences between the deltoid heads in Strength and Physique: High Tension Exercises for Muscular Growth. If you understand the differences in fiber makeup between the different muscle, then you can train them accordingly for maximum hypertrophy.