How to do a Skull Crusher
The skull crusher, or lying triceps extension, is performed on a flat bench by lowering a barbell toward your forehead and pressing it back up. It isolates the triceps, especially the long head, through a long range of motion. It suits intermediate lifters who have solid elbow control and want to add serious triceps size.
- Primary muscles
- Triceps (triceps brachii)
- Also works
- Forearms (wrist flexors), Anconeus
- Equipment
- Barbell, Flat bench
- Level
- Intermediate
Step by step
- Lie on a flat bench with your feet planted and hold a barbell overhand with your hands about shoulder-width or slightly narrower.
- Press the bar up so your arms are straight over your chest, then tilt them back slightly toward your head.
- Bend only at the elbows to lower the bar slowly toward your forehead or just behind it.
- Keep your elbows pointing toward the ceiling and roughly shoulder-width apart as you lower.
- Stop when the bar is an inch or two from your head and your triceps feel a full stretch.
- Extend your elbows to press the bar back to the start position without snapping into lockout.
Coaching cues
- Keep a slight backward angle in your upper arms to hold tension on the triceps at the top.
- Use an EZ-bar if a straight bar strains your wrists.
- Lower the bar slowly; control matters more than load on this lift.
Common mistakes
Elbows flaring out
Keep your elbows in line with your shoulders and reduce the weight if they splay.
Turning it into a press
Keep your upper arms still so the movement happens at the elbow only.
Going too heavy
Pick a load you can lower slowly for every rep, and use a spotter when pushing close to failure.
Sets and reps
Strength
3–4 sets of 6–8 reps
Muscle growth
3–4 sets of 8–12 reps
Endurance
2–3 sets of 15–20 reps
Alternatives
FAQ
Are skull crushers hard on the elbows?
They can be if you go too heavy or move too fast. A moderate weight, slow lowering, an EZ-bar and a proper warm-up make them more comfortable for most people.
Do skull crushers work the long head of the triceps?
Yes. With your arms angled back slightly, the long head works through a good stretch, which makes skull crushers a strong choice for overall triceps size.
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