Arm Muscle: Building the Side Biceps, Brachialis, and Brachioradialis

How do you build muscle on the side of your biceps?

Building muscle that appears on the "side" of your biceps primarily involves developing the brachialis and brachioradialis muscles, which lie beneath and beside the biceps brachii, respectively, contributing significantly to overall arm thickness and width.

Understanding Arm Anatomy for Comprehensive Development

To effectively build muscle that gives the appearance of "side" development, it's crucial to understand the primary muscles of the upper arm and forearm responsible for elbow flexion:

• Biceps Brachii: This is the most visible muscle on the front of your upper arm, responsible for elbow flexion (bending the arm) and forearm supination (rotating the palm upwards). It has two heads:
  • Long Head: Contributes to the "peak" of the biceps.
  • Short Head: Contributes to the overall mass and width of the biceps.
• Brachialis: Located directly underneath the biceps brachii, the brachialis is a pure elbow flexor. It does not assist in supination. When well-developed, it pushes the biceps brachii upwards, creating a higher "peak" and adding significant thickness to the arm, especially when viewed from the side.
• Brachioradialis: While technically a forearm muscle, the brachioradialis originates high on the humerus (upper arm bone) and inserts on the forearm. It is a strong elbow flexor, particularly when the forearm is in a neutral (hammer) grip position. Its development adds considerable mass to the outer aspect of the forearm and contributes to the perceived "side" thickness of the upper arm, bridging the gap between the bicep and forearm.

Therefore, targeting the brachialis and brachioradialis, in conjunction with overall biceps brachii development, is key to achieving a thicker, wider arm profile.

The Brachialis: Your Arm's Hidden Powerhouse

The brachialis is a workhorse of elbow flexion. Because it lies beneath the biceps, its growth literally pushes the biceps out, making the arm appear thicker and giving the biceps a higher peak. To emphasize the brachialis, exercises that minimize the contribution of the biceps brachii's supination function are effective.

• Key Principle: The brachialis is most active when the hand is pronated (palms down) or in a neutral grip (palms facing each other), as this reduces the mechanical advantage of the biceps brachii.

The Brachioradialis: Adding Forearm and Upper Arm Thickness

The brachioradialis is prominent on the thumb side of your forearm when flexed. Its development significantly enhances the transition from the upper arm to the forearm, making the entire arm appear more robust and thick from the side.

• Key Principle: The brachioradialis is highly engaged during elbow flexion when the forearm is in a neutral (hammer) grip.

Optimizing Biceps Brachii Development

While the focus here is on the "side," overall development of the biceps brachii is fundamental. Exercises performed with a supinated (palms up) grip will maximize biceps brachii activation, contributing to overall arm mass and peak.

Key Principles for Muscle Hypertrophy

Regardless of the specific muscle, consistent application of hypertrophy principles is essential:

• Progressive Overload: Continuously challenge your muscles by gradually increasing resistance, repetitions, or training volume over time.
• Proper Form: Execute exercises with strict form to ensure the target muscles are effectively stimulated and to prevent injury.
• Adequate Volume: Aim for 10-20 sets per muscle group per week, spread across 2-3 training sessions.
• Time Under Tension: Control the eccentric (lowering) phase of each repetition to maximize muscle fiber recruitment.
• Mind-Muscle Connection: Focus on feeling the target muscle work throughout the entire range of motion.

Sample Exercises for Comprehensive Arm Development

To target the brachialis, brachioradialis, and overall biceps, incorporate a variety of curl variations:

• Hammer Curls (Neutral Grip):
  • Target: Primarily brachialis and brachioradialis.
  • Execution: Hold dumbbells with palms facing each other. Curl the weights up towards your shoulders, keeping the neutral grip.
  • Why it works: The neutral grip minimizes biceps supination, forcing the brachialis and brachioradialis to work harder as primary elbow flexors.
• Reverse Curls (Pronated Grip):
  • Target: Primarily brachialis, secondary brachioradialis, and forearm extensors.
  • Execution: Hold a barbell or dumbbells with an overhand (pronated) grip, palms facing down. Curl the weight up, keeping elbows tucked.
  • Why it works: This grip almost completely removes the biceps brachii's supination advantage, isolating the brachialis and challenging the brachioradialis significantly.
• Preacher Curls (Varying Grips):
  • Target: Isolates the biceps brachii, but can be adapted for brachialis.
  • Execution: Use a preacher curl bench.
    • Supinated Grip: Maximizes biceps peak and overall mass.
    • Neutral Grip (Dumbbell): Increases brachialis and brachioradialis involvement.
    • Pronated Grip (EZ Bar or Straight Bar): Highly effective for isolating the brachialis.
  • Why it works: The fixed position of the upper arm minimizes momentum and forces the target muscles to work harder through the range of motion.
• Zottman Curls:
  • Target: Comprehensive arm development (biceps brachii, brachialis, brachioradialis).
  • Execution: Curl dumbbells up with a supinated (palms up) grip. At the top, rotate your wrists to a pronated (palms down) grip and slowly lower the weights. Rotate back to supinated for the next rep.
  • Why it works: Combines the benefits of supinated (biceps) and pronated (brachialis/brachioradialis) curls in one movement, emphasizing different muscles during the concentric and eccentric phases.
• Rope Hammer Curls (Cable Machine):
  • Target: Brachialis and brachioradialis with constant tension.
  • Execution: Attach a rope handle to a low cable pulley. Perform hammer curls, keeping a neutral grip throughout.
  • Why it works: Provides consistent tension throughout the range of motion, which can be beneficial for hypertrophy.

Programming Considerations

• Frequency: Train arms 2-3 times per week, allowing for adequate recovery between sessions.
• Volume: Aim for 3-4 sets of 8-15 repetitions per exercise. Adjust based on your recovery capacity and overall training split.
• Progression: Systematically increase the weight, reps, or sets over time. Alternatively, decrease rest periods or increase time under tension.

The Importance of Proper Form and Mind-Muscle Connection

Building muscle effectively, especially in smaller, specific areas, hinges on meticulous form. Avoid swinging or using momentum. Focus on a controlled concentric (lifting) phase and a slow, controlled eccentric (lowering) phase. Actively think about squeezing the target muscle during each repetition. This mind-muscle connection ensures you're engaging the intended muscles rather than relying on other muscle groups or momentum.

Nutrition and Recovery: The Pillars of Growth

Even the most perfectly executed training program will yield limited results without adequate support from nutrition and recovery.

• Protein Intake: Consume sufficient protein (e.g., 1.6-2.2 grams per kilogram of body weight) to support muscle repair and growth.
• Caloric Surplus: To build muscle mass, you generally need to consume slightly more calories than you burn.
• Sleep: Prioritize 7-9 hours of quality sleep per night, as this is when most muscle repair and growth occurs.

Conclusion: A Holistic Approach to Arm Development

Building muscle on the "side" of your biceps is not about isolating an imaginary part of the biceps brachii, but rather about strategically developing the supporting muscles that contribute to overall arm thickness and width. By incorporating exercises that specifically target the brachialis and brachioradialis alongside traditional biceps exercises, applying principles of progressive overload, and prioritizing nutrition and recovery, you can achieve a more comprehensive, powerful, and aesthetically impressive arm development.