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  7. Dumbbell Seated Bench Extension

Exercise guide

Dumbbell Seated Bench Extension

  • Intermediate
  • Isolation
  • Rep-based
  • Chest
  • Upper arms

This isolation movement targets all three heads of the triceps, with a specific emphasis on the long head due to the overhead arm position. It provides a deep stretch at the bottom of the movement, which is highly effective for muscle growth and overhead stability.

Reviewed by the Crucible team · Updated June 2026

Watch the Dumbbell Seated Bench Extension demonstrationGuided video and your full workout live in the Crucible app.

Muscles worked

Primary

  • Triceps

Secondary

  • Abs
  • Obliques

Equipment

  • Dumbbell

Setup

  1. Sit upright on the end of a flat bench with your feet firmly planted on the floor for stability.
  2. Grasp a single dumbbell with both hands, forming a diamond shape with your palms against the underside of the top weight plate.
  3. Lift the dumbbell directly overhead until your arms are fully extended, keeping your chest up and shoulders down.

How to do it

  1. Inhale as you slowly lower the dumbbell behind your head by bending only at the elbows, keeping your upper arms vertical and tucked close to your ears.
  2. Lower the weight in a controlled manner until your forearms reach at least parallel to the floor or you feel a deep stretch in the triceps.
  3. Exhale as you drive the weight back up to the starting position by extending your elbows, following a 2-0-2 tempo.

Form checklist

  • Keep your elbows pointed forward rather than flaring them out to the sides.
  • Maintain a neutral spine and avoid excessively arching your lower back to compensate for the weight.
  • Ensure your upper arms remain stationary throughout the movement; only the forearms should move.
  • Keep your core braced to prevent your ribcage from flaring upward.

Pro tips

  • Pause for one second at the bottom of the rep to maximize the stretch on the long head of the triceps.
  • Focus on squeezing the triceps hard at the top of the movement without locking out the elbows aggressively.

Make it harder

  • Increase the time under tension by using a 4-second eccentric (lowering) phase.
  • Transition to a unilateral (one-arm) variation to increase the stability requirement and address muscle imbalances.

Frequently asked

What muscles does the dumbbell seated bench extension work?
The dumbbell seated bench extension primarily targets the triceps, and also works the abs and obliques as secondary muscles.
What equipment do you need for the dumbbell seated bench extension?
The dumbbell seated bench extension uses dumbbell.
Is the dumbbell seated bench extension good for beginners?
The dumbbell seated bench extension is rated intermediate. Build a base with simpler variations first, then progress to it with light load and strict form.

Related exercises

  • Arm Double CrossoverIntermediate · biceps, deltoids, and triceps
  • Aztec Push UpIntermediate · pectorals, serratus anterior, and triceps
  • Band Assisted DipIntermediate · triceps
  • Band Incline Triceps ExtensionIntermediate · triceps

Train this with a plan, not guesswork

Crucible builds the dumbbell seated bench extension into a precise program around your body, equipment, location, and time.

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