Triceps Brachii: Primary Actions, Secondary Roles, and Exercise Applications

What does the tricep move?

The triceps brachii muscle primarily extends the elbow joint, straightening the arm. Its long head also plays a secondary role in extending and adducting the shoulder joint.

Introduction to the Triceps Brachii

The triceps brachii, meaning "three-headed arm muscle," is the sole muscle on the posterior aspect of the upper arm. It is a critical component for arm function, enabling a wide range of movements. As its name suggests, it comprises three distinct heads:

• Long Head: Originates from the infraglenoid tubercle of the scapula (shoulder blade).
• Lateral Head: Originates from the posterior surface of the humerus (upper arm bone), superior to the radial groove.
• Medial Head: Originates from the posterior surface of the humerus, inferior to the radial groove.

All three heads converge to insert via a common tendon onto the olecranon process of the ulna (one of the forearm bones) and the posterior capsule of the elbow joint. This anatomical arrangement dictates its powerful actions.

Primary Actions of the Triceps Brachii

The most significant and primary action of the triceps brachii is elbow extension. This is the movement that straightens the arm at the elbow joint, moving the forearm away from the upper arm.

• Mechanism of Elbow Extension: When the triceps contracts, it pulls on its insertion point at the olecranon process of the ulna. Since the ulna forms part of the elbow joint, this pull levers the forearm backward, extending the arm. This action is crucial for pushing movements and for stabilizing the arm in an extended position.
• Role of Each Head in Elbow Extension: While all three heads contribute to elbow extension, the medial head is often considered the "workhorse" for most elbow extension movements, especially at lower loads. The lateral head contributes significantly to powerful and forceful elbow extension. The long head, due to its origin on the scapula, is most active when the shoulder is extended or adducted, or when the elbow extends from a flexed position.

Secondary Actions and Stabilization

Beyond its primary role in elbow extension, the triceps brachii, particularly its long head, contributes to other movements and plays a vital role in joint stabilization.

• Shoulder Extension and Adduction (Long Head): Because the long head originates on the scapula (crossing the shoulder joint), it can act on the shoulder. When the arm is raised (flexed) forward, the long head can assist in extending the shoulder (moving the arm backward). It can also contribute to adduction of the shoulder, pulling the arm towards the midline of the body. This dual-joint action makes the long head unique among the triceps heads.
• Joint Stabilization: The triceps provides significant stabilization to the elbow joint, especially during movements that load the joint in extension (e.g., holding a plank or performing a handstand). The long head also contributes to the stability of the shoulder joint by helping to hold the head of the humerus within the glenoid cavity.

Real-World Applications: Triceps in Movement and Exercise

Understanding what the triceps moves allows us to appreciate its importance in daily activities and targeted strength training.

• Pushing Movements: Any activity requiring you to push something away from your body heavily relies on triceps activation. Examples include:
  • Push-ups: Extending the elbows to lift the body.
  • Bench Press: Pressing weight away from the chest.
  • Overhead Press: Pushing weight above the head.
  • Throwing: The final phase of a throw involves powerful elbow extension.
  • Punching: Extending the arm for impact.
• Extension Movements: Exercises specifically designed to isolate and strengthen the triceps focus on elbow extension:
  • Triceps Pushdowns (Cable Pressdowns): Extending the elbows against resistance.
  • Overhead Triceps Extensions (Skullcrushers): Extending the elbows from an overhead or supine position.
  • Dips: Lowering and raising the body by flexing and extending the elbows.
  • Close-Grip Bench Press: A variation of the bench press that emphasizes triceps activation.

Importance of Strong Triceps

Developing strong triceps is not just for aesthetics; it's crucial for functional strength, athletic performance, and injury prevention. Strong triceps support:

• Upper Body Pushing Power: Essential for many sports and daily tasks.
• Elbow Joint Health: Strong surrounding musculature helps stabilize and protect the joint.
• Shoulder Stability: The long head's contribution aids overall shoulder health.
• Balance in Arm Strength: Counteracting the powerful biceps provides muscular balance.

Conclusion

The triceps brachii is a powerful and versatile muscle primarily responsible for extending the elbow joint, a fundamental movement for pushing and straightening the arm. Its long head offers additional contributions to shoulder extension and adduction, highlighting its role in complex upper body movements. By understanding these actions, individuals can effectively train their triceps for improved strength, function, and overall physical performance.