Kneeling Triceps Extensions

The kneeling triceps extension is a bodyweight arm exercise performed with your knees and hands on the floor. You lower your upper body by bending primarily at the elbows and then contract your triceps to straighten the arms. Using the knees as the pivot shortens the body lever, making this variation more accessible than a full-plank bodyweight triceps extension.

Some trainers call this movement a kneeling triceps push-up, bodyweight skull crusher or kneeling sphinx push-up. However, it is different from a standard knee push-up: during a knee push-up, the chest moves toward the floor through substantial movement at both the shoulders and elbows, while the kneeling triceps extension keeps the upper arms comparatively stable and emphasizes elbow flexion and extension.

The exercise is also different from a diamond push-up, which remains a compound chest, shoulder and triceps movement. Kneeling triceps extensions place more of the movement around the elbows, making them useful for developing the triceps strength required for push-up lockouts, dips and more advanced triceps extensions on a parallette.

The triceps brachii consists of three heads that join into a common tendon and primarily straighten the arm at the elbow, as explained in the NCBI anatomy overview of the triceps. Although the kneeling position reduces the resistance, the exercise can still place considerable stress on the elbows and wrists if performed too deeply or without control. Reduce the range or choose an elevated variation if you experience joint discomfort.

Kneeling triceps extensions primarily train the triceps brachii through repeated elbow flexion and extension. The shoulders and trunk work mainly to stabilize the upper arms and maintain the kneeling plank position.

Primary Muscle

• Triceps brachii: The long, lateral and medial heads of the triceps work together to extend the elbows and raise the body away from the floor.

All three heads combine into a common tendon at the elbow, and their principal shared function is elbow extension. The NCBI triceps anatomy reference identifies elbow extension as the muscle group’s primary function.

Secondary and Stabilizing Muscles

• Anconeus: This smaller muscle assists the triceps during elbow extension.
• Anterior deltoids: The front of the shoulders helps stabilize the upper arms as the body moves.
• Pectoralis major: The chest contributes to shoulder stability and provides limited assistance during the pressing phase.
• Serratus anterior: This muscle helps control the shoulder blades while your hands remain fixed against the floor.
• Forearm muscles: The wrist and forearm muscles stabilize the hands and wrists under load.
• Abdominals and obliques: The core resists extension and rotation so the torso moves as one controlled unit.
• Glutes: The gluteal muscles help keep the hips extended and prevent the body from folding backward.

Compared with a diamond push-up, the kneeling triceps extension reduces the contribution of the chest by limiting shoulder movement and concentrating more of the repetition around the elbows. The diamond push-up remains a useful related compound exercise when the goal is to train the chest, shoulders and triceps together.