FormTwin › Exercises › Skull Crusher

What muscles does the Skull Crusher work?

The skull crusher is a lying triceps isolation that stretches and loads all three triceps heads — a classic mass builder for the back of the arms.

Primary muscles worked

Secondary muscles worked

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How to do the Skull Crusher

  1. Lie on a bench holding an EZ-bar over your chest.
  2. Keep your upper arms vertical and still.
  3. Bend the elbows to lower the bar toward your forehead.
  4. Extend back up, squeezing the triceps.

Common mistakes

Variations

Overhead extensionDumbbell skull crusherTricep pushdown

Frequently asked questions

What muscles do skull crushers work?

Skull crushers isolate the triceps — all three heads. Taking the bar slightly behind the head increases the stretch on the long head, which is the largest of the three.

Are skull crushers bad for elbows?

They can irritate the elbows if you go too heavy or let the elbows flare. Keep the load moderate, elbows tucked, and lower under control to keep them joint-friendly.

Skull crusher vs pushdown?

Skull crushers load the triceps in a stretched position (great for the long head); pushdowns work them in a shortened position with constant tension. Using both builds the triceps fully.

Related exercises

DeadliftBack SquatBench PressPull-UpPush-Up

This guide is general fitness information, not medical advice. Muscle involvement varies with form, grip and individual anatomy. Consult a professional before starting a new program.