Dumbbell Skullcrusher

Definition

The dumbbell skullcrusher is a compound/isolation exercise targeting the triceps brachii. Lying supine on a bench, the athlete lowers dumbbells by bending the elbows until the weights reach beside the head, then extends the arms to lockout. The name comes from the path the weights travel toward the skull. It builds the tricep strength that supports sled pushes, wall balls, and overhead pressing in HYROX^®.

Technique & Form

1. Starting position - Lie on a flat bench holding dumbbells above the chest with arms extended, palms facing each other.
2. Lowering phase - Bend the elbows to lower the dumbbells toward the sides of the head. Keep the upper arms stationary; only the forearms move.
3. Extension phase - Extend the elbows to press the dumbbells back to the starting position. Squeeze the triceps at lockout.
4. Breathing - Inhale as you lower; exhale as you extend.
5. Tempo - 2 seconds down, 1 second up.

Muscles Worked

• Primary movers: Triceps brachii (all three heads)
• Stabilizers: Anterior deltoid, core

Common Mistakes

• Flaring the elbows - Elbows drifting out reduces tricep loading. Fix: keep the elbows shoulder-width apart throughout.
• Moving the upper arms - Letting the shoulders flex turns it into a pullover. Fix: lock the upper arms perpendicular to the floor.

Benefits

• Loads all three heads of the triceps through a full range of motion.
• Builds the elbow extension strength needed for sustained sled pushing.
• Allows heavier loading than kickbacks for greater tricep strength development.

HYROX^® Context

The skullcrusher builds the tricep strength that supports extended sled pushing and overhead wall ball pressing. Strong triceps delay the lockout fatigue that slows athletes during high-rep wall balls. Program 3 sets of 10-12 reps on push-day sessions, pairing with dumbbell bench press or dumbbell shoulder press.

Variations & Alternatives

• Dumbbell Tricep Extension - Overhead extension emphasizing the long head.
• Dumbbell Kickback - Light isolation for tricep endurance.
• Dumbbell Push Press - Compound pressing that trains triceps under heavier loads.

FAQ

Are skullcrushers safe for the elbows? Yes, when performed with controlled tempo and appropriate weight. If you feel elbow pain, reduce the weight, slow the tempo, or switch to overhead extensions.

How heavy should I go? 8-15 kg per dumbbell for most athletes. Prioritize controlled reps and a full range of motion over maximum load.

Track your tricep development and pressing strength with ROXBASE.