The triceps brachii muscle makes up the majority of the mass on the back of the upper arm, giving it the characteristic horseshoe shape many people seek to develop. This muscle group is composed of three distinct sections, or heads, that work together as the primary extensors of the elbow joint. While all three heads contribute to straightening the arm, specific training movements can shift the emphasis toward one head over the others. This article focuses specifically on the “short head,” also known as the medial head, and how to best target it for balanced arm development and overall triceps size.
Understanding the Medial Head of the Triceps
The medial head of the triceps is often called the short head because its origin point is lowest on the humerus bone compared to the other two heads. It arises from the posterior surface of the humerus, specifically below the radial groove, and is anatomically considered the deepest of the three heads. All three sections converge into a common tendon that inserts onto the olecranon process, the bony point of the elbow on the ulna bone.
The medial head is unique because it does not cross the shoulder joint, meaning it is a single-joint muscle. This anatomical characteristic makes its primary function the extension of the forearm at the elbow joint. Because it is mechanically less affected by shoulder position than the long head, the medial head is often described as the “workhorse,” providing consistent force regardless of whether the arm is overhead or by the side.
Biomechanical Principles for Short Head Activation
Targeting the medial head involves leveraging its mechanical role as the constant elbow extensor, especially when the long head is not being heavily stretched or recruited. The long head originates higher up on the scapula and is strongly activated when the arm is placed in an overhead position. Keeping the arm close to the torso minimizes the long head’s involvement, which relatively increases the demand on the medial and lateral heads.
A principle for stimulating the medial head is focusing on the final degrees of elbow extension, or the “lockout” phase of a movement. The medial head is active throughout the entire range of motion, but its contribution is significant in the terminal extension. This makes exercises that allow for a complete, forceful straightening of the elbow the most effective for this head.
Grip and forearm position can also influence muscle recruitment. Using a standard, overhand, or neutral grip for pushdown movements tends to keep the focus primarily on the lateral and medial heads. Keeping the elbows strictly tucked against the sides during these movements ensures that the long head is not contributing significantly to the movement.
Effective Exercises to Target the Short Head
The most direct way to isolate the medial head is through the Standard Cable Triceps Pushdown using a straight bar or V-bar attachment. To perform this exercise, stand facing the cable stack with the attachment gripped firmly, keeping the elbows pinned tightly against the sides of the body. The movement should be a strict, controlled press downward until the elbows are fully locked out, squeezing the triceps hard at the bottom. This arm-by-side position minimizes the contribution of the long head, forcing the medial and lateral heads to become the primary movers.
Dumbbell Kickback
Another effective variation is the Dumbbell Kickback, executed with a focus on strict form. Start by leaning over a bench with the non-working knee and hand supported, holding a dumbbell in the working hand. The upper arm should be raised until it is parallel to the floor and the torso, maintaining a fixed position throughout the set. The movement involves extending the elbow backward until the arm is completely straight, which places peak tension on the triceps at the point of maximum medial head activity.
Reverse-Grip Triceps Pushdown
The Reverse-Grip Triceps Pushdown utilizes an underhand, or supinated, grip on a straight bar attachment. This grip is employed to recruit the medial head more directly, and it helps to mechanically put the biceps at a disadvantage. Using a closer grip width also helps to keep the elbows tucked close to the body. The movement is executed with the same strict, controlled extension and forceful lockout as the standard pushdown.
Close-Grip Bench Press
Finally, the Close-Grip Bench Press is a mass builder that emphasizes the triceps, including the medial head. When performing this exercise, the hands should be positioned slightly narrower than shoulder-width apart. The elbows must be kept tucked tightly against the sides of the ribcage as the bar is lowered. This tucked elbow position shifts the stress away from the chest and onto the triceps. The medial head is heavily recruited during the pressing motion.