Cable Skull Crusher — how to, muscles worked, alternatives

How to do the Cable Skull Crusher

Lie on a bench, head toward the low pulley, feet flat on the floor.
Hold the bar above your shoulders with your arms straight.
Bend your elbows, lowering the bar in a curve towards your forehead.
Straighten your arms fully to return the bar above your shoulders.
Keep your upper arms fixed in place throughout the movement.

Full technique — 8 steps

Attach a bar to the low pulley and place a flat bench in front of the machine.
Lie on the bench with your head toward the machine and your feet flat on the floor.
Hold the bar with a shoulder-width grip and extend your arms straight above your shoulders.
Set your upper arms slightly back from vertical to keep tension on the triceps.
Bend your elbows and lower the bar in an arc toward your forehead or just behind it.
Stop when your elbows reach a deep bend and the bar is close without touching.
Extend your elbows to drive the bar back to the start position over your shoulders.
Finish with the elbows straight and upper arms still mostly fixed in place.

Common mistakes

Elbows flaring out wide
Turning it into a pullover
Letting upper arms drift backward
Stopping short of full extension
Cutting the bottom range short

Form cues

Move only at elbows
Keep wrists straight
Upper arms stay quiet
Lower behind forehead if needed

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 Triceps Pushdown (Rope) Beginner
This exercise Cable Skull Crusher Beginner
Harder Barbell Skull Crusher Intermediate

Too hard for now? Start with the Triceps Pushdown (Rope).

Quick answers

What muscles does the Cable Skull Crusher work?

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

When should I do the Cable 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 Cable Skull Crusher?

Strength: 3–4 sets of 6–8 reps, rest 1 min 45 s, 2 reps in reserve. Muscle growth: 3–4 sets of 10–15 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 Cable Skull Crusher?

Dumbbells: Seated Dumbbell Triceps Kickback, Bilateral Dumbbell Triceps Kickback. Machine: Ski Erg Triceps Pushdown, Ski Erg Triceps Extension. Resistance bands: Single Arm Resistance Band Triceps Pushdown, Resistance Band Triceps Kickback. Kettlebell: Kettlebell Overhead Triceps Extension, Kettlebell Skull Crusher.