Dumbbell Floor Skull Crusher — how to, muscles worked, alternatives

How to do the Dumbbell Floor Skull Crusher

Lie on the floor, knees bent, holding one dumbbell above your chest with both hands.
Keep your upper arms nearly vertical, elbows pointing toward the ceiling.
Bend your elbows to lower the dumbbell behind your head.
Straighten your arms back up to the starting position, feeling the triceps work.

Full technique — 6 steps

Lie on your back on the floor with knees bent and feet flat.
Hold one dumbbell with both hands, one palm cupping each end, and straighten your arms above your chest.
Use a neutral grip and set your upper arms nearly vertical with elbows pointing upward.
Tighten your stomach and keep your shoulders quiet as the movement comes only from the elbows.
Bend your elbows to lower the dumbbell behind your head until it is just above the floor.
Extend your elbows to drive the dumbbell back above your chest until your arms are straight.

Common mistakes

Upper arms drifting backward excessively
Turning it into a pullover
Elbows flaring wide apart
Cutting the bottom range short
Resting the dumbbell on the floor

Form cues

Move only at elbows
Keep upper arms still
Lower behind the head
Straighten arms completely

Substitutes by equipment

Same muscles, same movement — pick the version you have the gear for.

Where to start and where to go next

Same muscles, same movement. Too hard for now — step down; once it gets easy — step up.

Easier Bilateral Dumbbell Triceps Kickback Beginner
This exercise Dumbbell Floor Skull Crusher Beginner
Harder Dumbbell Skull Crusher Intermediate
Harder Bodyweight Triceps Extension 70% of bodyweight

Too hard for now? Start with the Bilateral Dumbbell Triceps Kickback.

Quick answers

What muscles does the Dumbbell Floor Skull Crusher work?

Primary: Triceps 10/10. Also works: Forearms 3/10, Lats 3/10, Front delts 3/10.

When should I do the Dumbbell Floor Skull Crusher in a workout?

Finisher. Goes last, once the heavy work is done. ≈ 6 min with rest.

How many sets and reps of the Dumbbell Floor Skull Crusher?

Strength: 3–4 sets of 6–8 reps, rest 2 min, 2 reps in reserve. Muscle growth: 3–4 sets of 8–12 reps, rest 1 min 15 s, 2–3 reps in reserve. Endurance: 2–3 sets of 15–20 reps, rest 45 s, 3–4 reps in reserve.

What can I do instead of the Dumbbell Floor Skull Crusher?

Cable machine: Cable Overhead Triceps Extension (EZ Bar), Cross Cable Triceps Pushdown. Resistance bands: Resistance Band Overhead Triceps Extension, Single Arm Resistance Band Triceps Pushdown. Machine: Ski Erg Triceps Extension, Ski Erg Triceps Pushdown. Kettlebell: Kettlebell Overhead Triceps Extension, Kettlebell Skull Crusher.