Barbell Skull Crusher
Also known as: skull crusher
- Secondary muscles
- Delts
- Body part
- Upper Arms
- Position
- Lying
- Laterality
- Bilateral (both sides together)
- Category
- Strength
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Among lying extensions, the straight-bar version lets you load heaviest, since both hands share one rigid bar and you can add small plates for years. Lowering to the forehead keeps the range shorter than the behind-head version, which shifts more of the work toward the lockout half of the rep.
How to do the Barbell Skull Crusher
- Lie flat on a bench with your feet flat on the ground and your head at the end of the bench.
- Hold the barbell with an overhand grip, hands shoulder-width apart, and extend your arms straight up over your chest.
- Keeping your upper arms stationary, slowly lower the barbell towards your forehead by bending your elbows.
- Pause for a moment when the barbell is just above your forehead, then extend your arms back up to the starting position.
- Repeat for the desired number of repetitions.
Tip: Keep a slight bend at the top on lying extensions to protect the elbow, but lock out fully on cable pushdowns.
Muscles worked
Primary
Triceps · Arms
The triceps straighten the elbow, and overhead variations stretch the long head at the bottom, so you should feel the whole back of the upper arm working with a hard squeeze at lockout.
Secondary
- Delts — The front delt holds the upper arm in position on overhead extensions and should feel tension but not be lifting.
Common mistakes
- Elbows flaring out — on overhead and lying extensions the elbows should stay pointed forward or up, not out to the sides, since flaring turns it into a press.
- Upper arm moving — the upper arm should be pinned in place and only the forearm should move; if the elbow drifts, drop the weight.
- Not finishing the rep — take every rep to a full triceps squeeze; on pushdowns that means a complete lockout for a count.
- Cutting the stretch — on overhead extensions let the weight travel down behind the head until you feel the long head stretch before pressing up.
Sets, reps and where it fits
| Goal | Sets × reps | Rest |
|---|---|---|
| Muscle growth | 3–4 × 10–15 | 60–90 s |
| Endurance / finisher | 2–3 × 15–20 | 45 s |
| Strength | Not ideal — pick a compound lift for the same muscle | — |
Triceps extensions go after the presses in a push session or at the end of an arm day. Superset them with biceps curls on the same cable stack or with the same dumbbells.
Variations and alternatives
Similar exercises
Without barbell
Frequently asked questions
What muscles does the Barbell Skull Crusher work?
The Barbell Skull Crusher primarily works the triceps. It also involves the delts, which assist the movement and stabilise the joints.
Is the Barbell Skull Crusher good for beginners?
It is rated intermediate, so it suits people who already train regularly. Beginners can still do the Barbell Skull Crusher with light load and a spotter or coach watching the first few sessions; if it feels awkward, pick an easier variation from the alternatives below first.
What can I do instead of the Barbell Skull Crusher?
If you cannot do the Barbell Skull Crusher, try the Kneeling Bodyweight Triceps Extension, the Seated Barbell Overhead Triceps Extension or the Decline EZ-Bar Skull Crusher. Each of them trains the triceps through a similar movement, so you can swap them in without changing the rest of the workout.
How many sets and reps should I do?
It depends on your goal. For the Barbell Skull Crusher, a sensible starting point is muscle growth: 3–4 × 10–15 with 60–90 s rest; endurance / finisher: 2–3 × 15–20 with 45 s rest. Do it after your compound lifts. It is a finishing movement, not the main event.
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More exercises
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- Straight Bar Cable Lying Triceps Extension
- Rope High Pulley Cable Overhead Triceps Extension
- Cable Overhead Triceps Extension
- Single Arm Cable Overhead Triceps Extension
Exercise data and animations are licensed ExerciseDB content used in SetGrip. This page is for general information and is not medical or coaching advice.