Dumbbell Skull Crusher
- Secondary muscles
- Delts
- Body part
- Upper Arms
- Position
- Lying
- Laterality
- Bilateral (both sides together)
- Category
- Strength
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Two independent dumbbells separate this from the barbell skull crusher in a useful way: each arm carries its own load, so a stronger side cannot quietly take over, and the neutral grip sits easier on the wrists than a straight bar. The tradeoff is stability; total weight will be lower, and control matters more than load.
How to do the Dumbbell Skull Crusher
- Lie flat on a bench with a dumbbell in each hand, palms facing each other.
- Extend your arms straight up over your chest, keeping your elbows close to your body.
- Lower the dumbbells down towards your forehead, bending your elbows.
- Pause for a moment, 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.
Where it fits in a workout
Triceps extensions go after the presses in a push session or at the end of an arm day. Superset them with biceps curls.
How many sets, how heavy and how hard: see what the ACSM position stands support.
Variations and alternatives
Similar exercises
Without dumbbell
When to talk to someone
- Chest discomfort, feeling faint or lightheaded, or trouble breathing during or after exercise can be signs of a heart attack. In the US, call 911 right away; elsewhere, call your local emergency number.
- Heart, metabolic or kidney disease, or symptoms like these when you are active: talk to your doctor before you start or step up training.
- Pregnant: ask your obstetric care provider which exercise suits you.
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More exercises
- All arms exercises
- All triceps exercises
- All dumbbell exercises
- Dumbbell triceps exercises
- Behind Head Close Grip Barbell Lying Triceps Extension
- Barbell Overhead Triceps Extension
- Seated Barbell Overhead Triceps Extension
- Seated Close Grip Barbell Overhead Triceps Extension
- Behind Head Barbell Skull Crusher
- Reverse Grip Barbell Skull Crusher
Sources
- ACSM position stand on exercise quantity and quality (Garber et al., 2011)
- ACSM preparticipation health screening (Riebe et al., 2015)
- ACOG Committee Opinion No. 804 on exercise in pregnancy (2020)
- CDC: About Heart Attack Symptoms, Risk, and Recovery (2024)
Sources checked on October 17, 2026. Full citations are in the exercise library.
Animation and exercise data: ExerciseDB, licensed to SetGrip. General information, not medical or coaching advice.