Skull Crusher: how to do it right
In short: The skull crusher isolates the triceps by heavily loading their long head in the stretched position, arms overhead.
How to do it, step by step
- 1Lying on the bench, EZ bar held with a close grip, arms extended and angled slightly backward (toward your forehead, not toward your feet).
- 2Bend the elbows to bring the bar toward your forehead or just behind it, elbows staying pointed up without flaring out.
- 3Lower under control over 2 to 3 seconds to the full stretch of the triceps, with no bounce.
- 4Press back up by extending the elbows, without locking out harshly at the top.
- 5Keep the arms stable: the elbow does the work, not the shoulder.
The mistake to avoid
Don't flare your elbows as you lower the bar toward your forehead.
Other common mistakes
- Elbows flaring outward: keep them tight and pointed up to target the triceps and protect the joint.
- Free-fall lowering with a bounce off the forehead: brake over 2 to 3 seconds, that's where the work happens.
- Moving the shoulder to help: lock the arm, only the elbow should open and close.
- Load too heavy that cuts the range: go lighter to reach the full stretch under control.
Muscles worked
- Main:
- Triceps
Triceps brachii, the only real prime mover. The long head, which crosses the shoulder and attaches on the shoulder blade, is especially engaged because the arm is angled backward, which pre-stretches it. The lateral and medial heads complete the elbow extension. The anconeus stabilizes at the end of the movement.
What to replace it with
Same muscle, same part of the movement: these exercises do the same job.
- Seated EZ-Bar Overhead Extension ›
- Standing Dumbbell Overhead Triceps Extension ›
- Two-Hand Overhead Dumbbell Extension ›
- Overhead Rope Triceps Extension ›
- Single-Arm Overhead Cable Extension ›
Frequently asked questions
How do I do this exercise?
Lying on the bench, EZ bar with a close grip, arms extended and angled slightly backward (toward your forehead, not toward your feet). Bend only the elbows to bring the bar toward your forehead or just behind it, elbows pointing up without flaring. The shoulder stays fixed, the elbow opens and closes.
How far down should I go?
Lower to the full stretch of the triceps, bar close to the forehead or just behind the head. That's where the tension is maximal and most useful. Brake this lowering over 2 to 3 seconds, with no bounce off the forehead, and go for the range you truly control, not the one you reach by wriggling.
I don't feel anything, is that normal?
You should feel your triceps, especially the long head. Deliberately angle the arms backward instead of holding them vertical: the bar goes toward the forehead or even slightly behind the head. This placement puts the long head in maximum stretch and makes the exercise far more effective than a pushdown.
How fast do I do the movement?
Brake the lowering toward the forehead over 2 to 3 seconds, the muscle in the lengthened position is what triggers the work. Press back up firmly but under control, without locking the elbows harshly. No bounce, ever.
How do I breathe?
Inhale and slightly hold the air as the bar lowers toward the forehead, it braces the torso and stabilizes your shoulders on the bench. Exhale during the press back up, at the end of the extension. Keep your abs engaged and glutes squeezed so you don't arch your lower back.