Seated Dumbbell Triceps Extensions (How To, Muscles Worked)

The Seated Dumbbell Tricep Extension is an overhead triceps exercise that builds strength and size in the back of the arms.

By pressing a dumbbell overhead and lowering it behind the head, you put the triceps under a deep stretch, making this one of the most effective isolation moves for arm development.

Primary Muscles Worked: Triceps Brachii
Secondary Muscles Worked: Shoulders (stabilization), Core (stabilization)
Equipment Needed: Dumbbell and Bench (optional back support)

How To Do Seated DB Tricep Extension

Step-by-Step Instructions

Set-Up:
- Sit tall on a bench with feet flat on the floor.
- Hold a dumbbell with both hands, palms pressed against the inside of the top plate or handle.
- Raise the dumbbell overhead until your arms are fully extended.
Execution:
- Keeping your elbows close to your ears, bend them to lower the dumbbell behind your head in a controlled arc.
- Lower until you feel a comfortable stretch in the triceps.
- Press the dumbbell back up to the starting position by extending your elbows.
Tips for Proper Form:
- Keep elbows pointed forward and close to your head (don’t let them flare).
- Brace your core to avoid arching your lower back.
- Use a controlled tempo. Avoid bouncing the dumbbell out of the bottom.

Key Benefits

Strong triceps isolation with a full stretch and contraction.
Builds lockout strength for pressing movements.
Seated position increases focus by removing leg drive and momentum.

Modifications and Variations

Easier Option:
- Use a lighter dumbbell to refine form.
- Perform the movement standing if you don’t have a bench.
Harder Option:
- Perform with two dumbbells (one in each hand) for unilateral balance.
- Slow down the eccentric (lowering) phase for more time under tension.
- Add a pause at the bottom for increased difficulty.

Common Mistakes

Elbows Flaring Out: Keep them tucked for maximum triceps engagement.
Overarching the Back: Keep ribs down and core tight.
Dropping Too Low: Only lower as far as mobility and control allow.

Reps and Sets Recommendations

For Strength: 3–4 sets of 6–8 reps with heavier load.
For Hypertrophy: 3–4 sets of 8–12 reps with moderate load.
For Endurance/Finisher: 2–3 sets of 12–15+ reps with lighter load.

Seated DB Triceps Extensions Alternatives

Can’t do Seated Dumbbell Extensions? Here are a few alternatives you might be able to try out instead.

Dumbbell Skull Crushers

If you’re looking for another triceps exercise using dumbbells, I would suggest Dumbbell Skull Crushers.

If you have limited shoulder mobility you may find Dumbbell Skull Crushers much more comfortable to perform because you don’t have to reach the dumbbell back behind the head. They can also be a good option if you don’t have heavy enough dumbbells for Seated Extensions because the weight needed for Skull Crushers will be less.

Band Triceps Pushdowns

If you have access to resistance bands, one of the easiest (and most effective) exercises to set up for triceps is Band Triceps Pushdowns.

Loop a resistant band around the top of a squat rack and perform triceps pushdowns just like you would with a cable machine.

Dips

I can’t not mention Dips here as an alternative, the king of all triceps exercises. If you really want to develop strong triceps, you should absolutely have Dips somewhere in your workout program.