Focus on the brachialis and brachioradialis
The main flexors of the upper arm include the two heads of the biceps, the brachialis and brachioradialis. However, if you look at most exercise programs, you will rarely see exercises that focus on the brachialis or brachioradialis.
This is the main reason to focus on these two muscle groups. They have been neglected and proportionally understrained, making them an easy target for rapid growth.
Most people can quickly increase the size of the upper arm by focusing on the brachialis and brachioradialis for six weeks. How you do that? First by varying your grip.
Use the hammer (neutral) and pronated (reverse) handle to focus on the brachialis. Also, use a slower rate of contraction (about two seconds up and four seconds down ̵
To focus on the brachioradialis, any shape of the inverted curl (palms down) is your best bet. To increase your reliance on this muscle, use a faster rate of contraction (without cheating) than that at which you would target the brachialis.
Good brachialis exercises include:
- Dumbbell Hammer Curl (with a slow eccentric)
- Rope Hammer Curl (hold tip contraction for two seconds on each rep)
- Cable Reverse Curl (hold with forearms parallel to the floor and a slow eccentric)
- Barbell hammer sits on an incline bench (hold the tip contraction for two seconds on each rep)
Good brachioradialis exercises include:
- Zottman Curl (raise palms up, lower palms down)
- EZ-Bar Reverse Curl (at normal pace)
- Dumbbell Reverse Curl (sits on an incline bench)
Start your biceps workout with a close-grip pull-up (this time I would actually use a pronation grip), then use 3-4 other exercises that you choose from the movements listed above. With each of these workouts, hold the pull-up and focus on improving performance for 6-8 reps. The other 3-4 exercises can be rotated if you’d like, and the reps should be between 8-12.
Do not do biceps dominant exercises for 4-6 weeks. That means any curl with a supinated or palm grip. Instead, specialize in brachialis and brachioradialis. Don’t worry, your arms will still be fully stimulated from your other exercises. And they’ll respond even better if you train them directly again.
Related: 5 Biceps Workout Tricks You Haven’t Tried Before
Related: The Hammer-Grip Kettlebell Drop Set