Exercise guide
Dumbbell Lying Single Extension
- Intermediate
- Isolation
- Rep-based
- Chest
- Upper arms
This isolation exercise targets the triceps, specifically the long head, while the alternating pattern helps identify and correct unilateral strength imbalances.
Reviewed by the Crucible Fit team · Updated June 2026
Muscles worked
Setup
- Lie flat on a bench with your feet planted firmly on the ground for stability.
- Hold a dumbbell in each hand with a neutral grip (palms facing each other).
- Extend both arms straight up over your chest, perpendicular to the floor.
How to do it
- Lower one dumbbell toward your shoulder by bending only at the elbow, keeping the upper arm completely vertical.
- Inhale as you lower the weight in a controlled 2-second eccentric phase until the dumbbell is near your ear.
- Exhale and contract the triceps to extend the arm back to the starting position.
- Repeat the movement with the opposite arm, alternating sides for the duration of the set.
Form checklist
- Keep the elbows tucked in and pointing toward your knees, not flaring out to the sides.
- Ensure the upper arm remains stationary; only the forearm should move.
- Maintain a neutral spine by keeping your head and back flat against the bench.
- Avoid locking out the elbows aggressively at the top to maintain tension on the muscle.
Pro tips
- Imagine your upper arm is bolted in place to ensure the movement remains a pure elbow extension.
- Focus on a deep stretch at the bottom of the rep to fully engage the triceps' long head.
Make it harder
- Incorporate a 2-second pause at the bottom of the movement to increase time under tension.
- Perform the exercise on a slight decline bench to increase the stretch and range of motion.
Frequently asked
- What muscles does the dumbbell lying single extension work?
- The dumbbell lying single extension primarily targets the triceps, and also works the abs and obliques as secondary muscles.
- What equipment do you need for the dumbbell lying single extension?
- The dumbbell lying single extension uses dumbbell.
- Is the dumbbell lying single extension good for beginners?
- The dumbbell lying single extension is rated intermediate. Build a base with simpler variations first, then progress to it with light load and strict form.