Skull Crushers (How To, Muscles Worked, Benefits)

Skull Crushers are a triceps isolation exercise usually performed with an EZ-bar, barbell, or dumbbells while lying on a bench.

By bending and extending at the elbows, you directly target the triceps, making this one of the most effective accessory lifts for building pressing strength and arm size.

Primary Muscles Worked: Triceps Brachii
Secondary Muscles Worked: Forearms (stabilization), Shoulders (minimal stabilization)
Equipment Needed: EZ-Bar, Barbell, or Dumbbells; Flat Bench

How To Do Skull Crushers

Step-by-Step Instructions

Set-Up:
- Lie on a flat bench holding an EZ-bar or barbell with arms fully extended above your chest (can also be done with dumbbells).
- Grip should be about shoulder-width if using a bar.
- Keep your upper arms vertical and elbows pointing toward the ceiling.
Execution:
- Bend at the elbows to slowly lower the weight toward your forehead (or just behind the head for safer range).
- Keep upper arms still. Only your forearms should move.
- Extend your elbows to press the weight back up to the starting position.
Tips for Proper Form:
- Keep elbows tucked in, not flared out.
- Lower under control (don’t let the weight free-fall).
- Stop just short of locking out fully to maintain tension.

Key Benefits

Directly isolates the triceps for strength and hypertrophy.
Supports stronger pressing movements (bench press, overhead press).
Can be performed with multiple implements (barbell, dumbbells, cables).

Modifications and Variations

Easier Option:
- Use lighter dumbbells for more control.
Harder Option:
- Perform with a slow eccentric (3–5 seconds lowering).
- Do incline skull crushers to increase the stretch on the triceps.
- Add bands or chains for accommodating resistance.

Common Mistakes

Flaring Elbows Outward: Keep them tucked to target the triceps.
Moving the Upper Arms: Shoulders shouldn’t shift. Keep arms vertical.
Dropping Too Far Back: Don’t overstretch the elbows; control the range.

Reps and Sets Recommendations

For Strength: 3–4 sets of 6–8 reps with heavier weight.
For Hypertrophy: 3–4 sets of 8–12 reps with moderate weight.
As an Accessory/Finisher: 2–3 sets of 12–15 reps with lighter weight.

Skull Crusher Alternatives

If you’re not able to do Skull Crushers (or maybe you just want to change your workout up a bit), here are a few alternatives. If you’d even more options, check out my 10 favorite Barbell Skull Crusher Alternatives.

DB Skull Crushers

The most natural alternative for Skull Crushers is Dumbbell Skull Crushers. With dumbbells, turn your palms in (facing each other) and then lower the dumbbells down to just beside the ears.

If you don’t have a bar, but you have dumbbells, this would be my first recommendation.

Dips

If you have access to a dip rack attachment or a dip station, Dips are one of the best exercises you can do to build triceps strength.

Band Triceps Pushdowns

Don’t have a bar, but have a band? Hang the band off a rack or pull-up bar and do Band Triceps Pushdowns instead.