Brachialis Muscle: Anatomy, Benefits, and Effective Exercises

How do you hit your bicep brachialis?

To effectively target the brachialis muscle, you must employ exercises that minimize the involvement of the biceps brachii, primarily by utilizing pronated (reverse) or neutral (hammer) grip variations, which emphasize pure elbow flexion.

Understanding the Brachialis Muscle

Often overshadowed by the more prominent biceps brachii, the brachialis is a critical muscle for arm strength and development. While colloquially referred to as "bicep brachialis," it's important to understand that the brachialis is a distinct muscle, lying deep to the biceps brachii on the anterior aspect of the upper arm.

• Anatomy and Location: The brachialis originates from the anterior surface of the humerus (upper arm bone) and inserts onto the coronoid process and tuberosity of the ulna (one of the forearm bones).
• Primary Function: Unlike the biceps brachii, which flexes the elbow, supinates the forearm, and assists in shoulder flexion, the brachialis has only one primary action: pure elbow flexion. It is considered the workhorse of elbow flexion, responsible for a significant portion of the force generated during this movement, regardless of forearm position.

Why Target the Brachialis?

While the biceps brachii gets much of the attention, a well-developed brachialis offers significant benefits for both aesthetics and functional strength:

• Increased Arm Thickness: Because it lies underneath the biceps brachii, a larger brachialis muscle pushes the biceps upwards, contributing to a fuller, more peaked appearance of the upper arm. It adds width and thickness to the lower part of the arm, near the elbow.
• Enhanced Elbow Flexion Strength: As the primary elbow flexor, strengthening the brachialis directly translates to greater pulling strength and improved performance in exercises requiring elbow flexion, such as rows, pull-ups, and various curling movements.
• Injury Prevention: A strong, balanced muscular system around the elbow joint can contribute to joint stability and potentially reduce the risk of injury.

Biomechanics of Brachialis Activation

The key to isolating the brachialis lies in understanding its unique anatomical insertion. Since it inserts on the ulna, its function is solely elbow flexion, and it is not involved in forearm supination (turning the palm up) or pronation (turning the palm down). The biceps brachii, however, is a strong supinator.

Therefore, to minimize biceps brachii involvement and maximize brachialis activation:

• Eliminate Supination: By performing curls with a pronated (reverse) grip (palms facing down), you put the biceps brachii in a mechanically disadvantaged position for flexion, forcing the brachialis to take over as the primary mover.
• Reduce Supination Capability: A neutral (hammer) grip (palms facing each other) also reduces the biceps's supination contribution, allowing the brachialis and brachioradialis (another forearm flexor) to work more intensely.

Key Principles for Brachialis Activation

When performing exercises to target the brachialis, keep these principles in mind:

• Prioritize Form Over Weight: The brachialis is a smaller muscle. Using excessive weight can lead to compensatory movements from larger muscle groups (like the back or shoulders) or excessive biceps involvement.
• Full Range of Motion: Ensure you achieve a complete extension at the bottom of the movement and a full contraction at the top, without losing tension.
• Controlled Eccentric Phase: The lowering (eccentric) phase of the lift is crucial for muscle growth. Control the weight as you lower it to maximize time under tension.
• Minimize Shoulder Movement: Keep your elbows relatively fixed or slightly behind your body to isolate the elbow joint and prevent the anterior deltoids from assisting.

Effective Exercises for the Brachialis

Here are the most effective exercises for targeting the brachialis:

• Reverse-Grip Barbell Curls:
  • Execution: Stand holding a barbell with an overhand (pronated) grip, hands shoulder-width apart. Keep your elbows tucked in and curl the bar upwards, focusing on squeezing the forearms and upper arm.
  • Rationale: The pronated grip places the biceps brachii at a mechanical disadvantage for flexion, forcing the brachialis to work harder.
• Hammer Curls (Dumbbells):
  • Execution: Stand or sit holding a dumbbell in each hand with a neutral grip (palms facing each other). Curl the dumbbells upwards, keeping your palms facing each other throughout the movement.
  • Rationale: The neutral grip significantly reduces the biceps's supination function, allowing the brachialis and brachioradialis to contribute more to elbow flexion. Can be performed standing, seated, or on an incline bench for varying tension profiles.
• Preacher Curls (Reverse or Hammer Grip):
  • Execution: Position yourself on a preacher curl bench. Using either a pronated (overhand) grip or a neutral (hammer) grip with an EZ bar or dumbbells, perform curls, allowing your triceps to fully stretch at the bottom.
  • Rationale: The preacher bench fixes the humerus, isolating the elbow joint and preventing momentum or assistance from other body parts, thus maximizing the load on the brachialis.
• Concentration Curls (Hammer or Reverse Grip):
  • Execution: Sit on a bench, leaning forward with your elbow braced against your inner thigh. Use a neutral or pronated grip on a dumbbell and slowly curl the weight upwards, focusing on the contraction.
  • Rationale: This exercise offers maximal isolation and allows for a strong mind-muscle connection, ensuring the brachialis is the primary mover.
• Rope Hammer Curls (Cable Machine):
  • Execution: Attach a rope handle to a low pulley cable. Stand facing the machine, grasp the rope with a neutral grip, and perform curls, keeping your elbows tucked.
  • Rationale: Cables provide constant tension throughout the range of motion, which can be beneficial for muscle hypertrophy. The rope allows for a natural neutral grip.

Common Mistakes to Avoid

• Swinging the Weight: Using momentum negates the isolation of the brachialis and transfers tension to other muscle groups.
• Insufficient Range of Motion: Not fully extending the arm at the bottom or fully contracting at the top limits the muscle's work.
• Over-Reliance on Biceps: Failing to adopt appropriate grip variations will primarily work the biceps brachii, missing the brachialis.
• Ignoring the Eccentric Phase: Dropping the weight quickly rather than controlling its descent reduces the hypertrophic stimulus.

Integrating Brachialis Training into Your Routine

To effectively develop your brachialis, incorporate 1-2 of the suggested exercises into your arm or pull day routine. Aim for 2-4 sets of 8-15 repetitions per exercise, focusing on controlled movement and proper form. Listen to your body and progressively overload by gradually increasing weight, repetitions, or sets over time.

By understanding the unique role of the brachialis and applying specific training principles, you can effectively target this crucial muscle, leading to stronger, thicker, and more aesthetically balanced arms.