The desire for well-developed arms often focuses on creating a noticeable bicep “peak” and overall width. Achieving this distinct shape requires targeted training that moves beyond standard curling movements. The concept of working the “outer bicep” refers to prioritizing the growth of the long head, the muscle structure primarily responsible for both the height and lateral fullness of the arm.
Understanding Bicep Anatomy and the Long Head
The bicep is formally known as the biceps brachii, a two-headed muscle composed of the long head and the short head. The long head is situated on the lateral, or outer, side of the upper arm, and its development directly contributes to the bicep’s height when flexed. Because the long head crosses the shoulder joint, its activation is highly sensitive to the angle of the arm relative to the torso. Placing the arm in a position of hyperextension, or behind the body, stretches the long head before the curl begins. This pre-stretch creates a more favorable length-tension relationship, allowing the long head to generate greater force and receive a stronger growth stimulus.
Primary Exercises for Outer Bicep Development
The Incline Dumbbell Curl is highly effective for targeting the long head due to its specific setup. Sitting on an adjustable bench set to a 45- to 60-degree angle naturally places the upper arm behind the torso. This extended position creates a deep stretch on the long head, maximizing its involvement throughout the movement. As you curl the weight, focus on full supination, rotating the wrist so the pinky finger finishes higher than the thumb at the top of the contraction.
Another movement that shifts tension to the outer portion of the arm is the Dumbbell Hammer Curl. By holding the dumbbells with a neutral grip (palms facing each other), this curl strongly recruits the brachialis and the brachioradialis muscles. The brachialis lies directly beneath the biceps, and its growth pushes the bicep upward, contributing to overall arm thickness and making the long head appear taller. The neutral grip also emphasizes the long head over the short head.
For a unique contraction stimulus, the Drag Curl is useful, often performed with a barbell or EZ-bar. The key feature is that the bar is “dragged” vertically up the front of the body while the elbows are pulled backward. This deliberate backward movement keeps the upper arm in a posterior position relative to the torso. This action mechanically limits the involvement of the front deltoids and maintains high tension specifically on the long head of the bicep.
Optimizing Training Variables for Bicep Peak and Width
To maximize the growth response from these exercises, focus on tempo and mechanical adjustments. A focus on the eccentric, or lowering, phase can significantly increase time under tension for the muscle fibers. Aiming for a controlled descent of three to four seconds on every repetition ensures the muscle is working harder against the resistance, which is a powerful stimulus for muscle development.
Adjusting the grip on barbell or cable curls can subtly alter the muscle emphasis. Using a narrower grip, slightly inside shoulder-width, places a greater biomechanical load on the long head. Conversely, a wider grip tends to favor the short head, which contributes more to width than peak. Maintaining stationary elbows throughout any curling movement is important to prevent the shoulder from assisting, ensuring the biceps are the primary muscle performing the work.
For programming, perform 10 to 15 working sets for the biceps per week, spread across two to three training sessions. The majority of these sets should utilize a moderate weight that allows for a strict 6 to 12 repetition range, as this range is effective for promoting muscle growth. Prioritizing movements that place the long head under stretch, such as the Incline Dumbbell Curl, is an effective strategy for building the desired peak and lateral thickness.