The triceps brachii muscle, located on the back of the upper arm, is responsible for straightening the elbow joint. This muscle is composed of three distinct sections, or heads. Understanding the unique function of the long, lateral, and medial heads allows for the selection of specific exercises and techniques. Training all three heads is necessary for complete arm development.
Understanding the Three Triceps Heads
The triceps brachii is named for its three points of origin: the long, lateral, and medial heads. All three heads converge into a single tendon that attaches to the ulna, making them primary extensors of the elbow joint. Their distinct origins dictate how they are best activated during resistance training.
The lateral and medial heads are considered monoarticular, originating on the humerus and only crossing the elbow joint. The medial head is the deep workhorse, remaining active during almost all elbow extension movements. The lateral head, situated on the outer side of the arm, is recruited when higher forces are needed for extension.
The long head is structurally unique because it originates on the scapula, making it biarticular as it crosses both the shoulder and the elbow joint. This positioning means the long head contributes to both elbow extension and shoulder adduction (moving the arm toward the body). Because it crosses the shoulder, the long head requires specific arm positioning to achieve a full stretch and optimal engagement.
Maximizing Activation of the Long Head
Targeting the long head effectively requires placing the arm in a position of shoulder flexion, raising the arms overhead. This overhead position stretches the long head across the shoulder joint, increasing its activation and potential for muscle growth. Exercises like the Overhead Dumbbell Extension or Cable Overhead Extension are effective for achieving this stretch.
When performing an Overhead Dumbbell Extension, hold a single dumbbell vertically with both hands and press it directly overhead. Slowly lower the weight behind your head, ensuring the biceps remain close to the ears and the elbows point forward. This controlled movement maximizes the stretch placed on the long head.
For cable variations, such as the Cable Rope Overhead Extension, face away from the machine and pull the rope over your head. Step away from the machine to maintain constant tension throughout the entire range of motion, focusing on a deep stretch at the bottom. Keeping a neutral grip often feels more comfortable on the joints. Performing elbow extension exercises in an overhead position results in greater hypertrophy for the long head compared to training with the arms by the sides.
Isolating the Lateral and Medial Heads
The lateral and medial heads are preferentially targeted through movements where the upper arms remain fixed at the sides of the torso. These exercises primarily focus on the mechanics of the elbow joint, using variations in grip and implement to shift the emphasis between the two heads. The medial head is a consistent contributor to elbow extension, while the lateral head can be emphasized with specific hand positions.
Targeting the Lateral Head
To focus on the lateral head, the most effective exercises involve a pronated, or overhand, grip on a straight bar or V-bar pushdown attachment. The straight bar pushdown, performed with the palms facing the floor, places greater mechanical stress on the outer head due to the slightly different alignment of the forearm bones. Emphasize a full extension and a strong contraction at the bottom of the movement to maximize the lateral head’s recruitment.
Targeting the Medial Head
The medial head, which lies deeper beneath the other two, can be preferentially engaged using a supinated, or underhand, grip. The Reverse Grip Pushdown involves holding a straight bar with the palms facing up, which alters the biomechanics of the forearm and shifts the focus toward the medial head. Another effective variation is the close-grip push-up, where the elbows are kept close to the body, forcing the medial head to contribute significantly to the pressing motion.