Skull Crusher
Arms
Weight & Reps
EZ Bar
Skull crushers (lying tricep extensions) are performed lying on a bench, lowering the bar toward the forehead and extending back up. They target all three tricep heads with heavy loads.
How to Do Skull Crusher
- Lie on a bench holding an EZ bar or straight bar with a narrow grip, arms extended above your chest
- Lower the bar toward your forehead by bending only at the elbows
- Stop just above your forehead (or slightly behind it for more long head stretch)
- Extend your arms back to the start, squeezing the triceps at the top
Form Cues
- Lie on a bench holding an EZ bar or straight bar with a narrow grip, arms extended above your chest
- Lower the bar toward your forehead by bending only at the elbows
- Stop just above your forehead (or slightly behind it for more long head stretch)
- Extend your arms back to the start, squeezing the triceps at the top
Common Mistakes to Avoid
- Moving the upper arms — they should stay perpendicular to the floor while only the forearms move
- Lowering the bar to the nose instead of the forehead, which reduces the range of motion
- Flaring the elbows outward, which reduces tricep isolation and involves the chest
Muscles Worked
Primary
Triceps Brachii (Long Head)
Triceps Brachii (Lateral Head)
Secondary
Triceps Brachii (Medial Head)
Anconeus
Recommended Sets and Reps
Strength
4-5 sets
3-5 reps
3-5 min rest
Hypertrophy
3-4 sets
8-12 reps
60-90s rest
Endurance
2-3 sets
15-20 reps
30-60s rest
Variations and Alternatives
Frequently Asked Questions
What muscles does the skull crusher work?
Skull crushers target the long and lateral heads of the triceps brachii as primary movers, with the medial head and anconeus assisting. The lying position allows heavy loading of all three heads.
How much should a beginner skull crush?
Beginners typically skull crush 25-45 lbs (11-20 kg) with an EZ bar. Start light to master the elbow-only hinge and avoid actually hitting your forehead.
Skull crushers vs overhead extensions — which is better?
Skull crushers allow heavier loads and target the lateral head more, while overhead extensions provide a deeper long head stretch. Use skull crushers for overall tricep strength and overhead extensions for long head emphasis.
Watch Form Guide on YouTube
Search for Skull Crusher tutorials
Track Skull Crusher in IronStreak
Track your Skull Crusher progress privately — all data stays on your device. No account required. Free on iOS.