Exercise guide
Dumbbell Lying Floor Skullcrusher
- Beginner
- Isolation
- Rep-based
- Chest
- Upper arms
This isolation exercise targets all three heads of the triceps, particularly the long head, while using the floor to provide stability and a safe range of motion. It is highly effective for building arm strength and definition without the need for a bench.
Reviewed by the Crucible Fit team · Updated June 2026
Muscles worked
Setup
- Lie flat on your back on the floor with your knees bent and feet flat for stability.
- Hold a dumbbell in each hand using a neutral grip with palms facing each other.
- Extend your arms straight up toward the ceiling, aligning the weights directly over your shoulders.
How to do it
- Inhale as you slowly lower the dumbbells toward the sides of your forehead by bending only at the elbows.
- Keep your upper arms stationary and perpendicular to the floor throughout the entire descent.
- Exhale as you contract your triceps to press the weights back to the starting position.
- Maintain a controlled tempo, taking roughly two seconds to lower the weights and two seconds to press them back up.
Form checklist
- Keep your elbows tucked in and pointing toward your feet; do not let them flare out to the sides.
- Ensure your lower back remains pressed firmly against the floor to prevent arching.
- Move only at the elbow joint; your shoulders and upper arms should remain completely still.
- Stop the descent just before the dumbbells touch the floor to maintain tension.
Pro tips
- Angle your upper arms slightly back toward your head (about 10-15 degrees) to keep constant tension on the triceps at the top of the rep.
- Focus on the mind-muscle connection by imagining you are pushing the floor away from the weights at the peak of the contraction.
Make it harder
- Incorporate a 'dead stop' at the bottom by letting the dumbbells briefly rest on the floor before exploding upward.
- Perform the exercise unilaterally (one arm at a time) to increase core engagement and address strength imbalances.
Frequently asked
- What muscles does the dumbbell lying floor skullcrusher work?
- The dumbbell lying floor skullcrusher primarily targets the triceps, and also works the biceps and forearms as secondary muscles.
- What equipment do you need for the dumbbell lying floor skullcrusher?
- The dumbbell lying floor skullcrusher uses dumbbell.
- Is the dumbbell lying floor skullcrusher good for beginners?
- Yes. The dumbbell lying floor skullcrusher is a beginner-friendly movement and a strong foundation to build on.