Skull crusher (lying triceps extension)
The skull crusher is a lying elbow extension with the arm at about shoulder height, a position between the pushdown and the overhead extension. It builds the triceps like any hard elbow extension, but no trial has measured growth from skull crushers specifically. Overhead extensions have better direct evidence; use skull crushers as a variation.
What the science says
- Builds the triceps like other elbow extensions Moderate evidence
Elbow extension training grew the triceps in both arm positions in Maeo et al. (2023), and the skull crusher works the same joint action. No skull-crusher-specific growth trial exists, so the grade is moderate.
- Activation is similar to overhead extensions Moderate evidence
Alves et al. (2018) compared lying and overhead dumbbell extensions in 21 trained men and found similar activation patterns for the triceps long and lateral heads. Activation is not growth.
- No proof it beats overhead work Limited evidence
With the arm at shoulder height, the long head is stretched less than overhead, where Maeo et al. found the greatest growth. Whether the skull crusher sits between the two for growth is untested.
How to do it
Muscles trained: triceps
- Lie on a bench holding an EZ bar or dumbbells over the shoulders
- Tilt the upper arms slightly back toward the head
- Bend only at the elbows, lowering the weight behind the top of the head
- Keep the elbows roughly shoulder-width; don't let them flare
- Extend to straight arms without moving the upper arms much
How to apply it
Use skull crushers as a triceps variation with an EZ bar or dumbbells; if you only have time for one triceps exercise, choose an overhead extension.
Who should be careful
For healthy adults it is safe with controlled loads; the main risk is losing control of the bar over the face, so use a spotter or dumbbells when going close to failure. Elbow pain is a reason to switch to an EZ bar, dumbbells or a cable, and to see a physician or physical therapist if it persists.
Frequently asked questions
Are skull crushers good for the triceps?
Yes, they train the triceps like other elbow extensions, but no trial has measured growth from skull crushers specifically. Overhead extensions have better direct evidence.
Should I do skull crushers and overhead extensions together?
Alves et al. found their activation patterns similar, so one is usually enough in a session. If you pick one, choose the overhead extension.
Why do skull crushers hurt my elbows?
Heavy straight-bar work can stress the elbows. Try an EZ bar or dumbbells, lighter loads with more reps, and see a physician or physical therapist if pain persists.
Scientific references
More exercises
- Back squat Strong evidence
The barbell back squat reliably builds the quadriceps, glutes and adductors and is one of the best-studied lower-body exercises in training research.
- Front squat Moderate evidence
The front squat holds the bar on the front of the shoulders, which keeps the torso more upright and loads the knees less than the back squat while recruiting the thigh muscles about as much.
- Bulgarian split squat Moderate evidence
The Bulgarian (rear-foot-elevated) split squat trains one leg at a time and builds the quads and glutes with far less load on the bar than a back squat.
- Leg press Strong evidence
The leg press builds the quadriceps about as well as free-weight squats and also grows the glutes and adductor magnus, with no balance or spinal-loading limit.
- Hack squat (machine) Moderate evidence
The machine hack squat lets you squat deep on a fixed track with your back supported, which makes it easy to push the quads close to failure.
- Romanian deadlift Moderate evidence
The Romanian deadlift is a hip hinge that loads the hamstrings and glutes at long muscle lengths, and trials of stiff-leg deadlifts and similar hip-extension exercises show real hamstring growth, mainly in the semimembranosus and biceps femoris long head.