Dumbbell Lying Triceps Extension
Lie flat on a bench with a dumbbell in each hand, arms straight and elbows directly above your shoulders. From there, bend your elbows and slowly lower the dumbbells as far as you can beside your head. Then straighten your arms powerfully until they are fully extended.
This exercise goes by several names: dumbbell lying triceps extension, dumbbell lying triceps curl, lying triceps press or dumbbell skull crusher. They all describe the same movement.
It trains your triceps, the three-headed muscle at the back of your upper arm that straightens your elbow. Your upper arms stay steady above your shoulders while your elbows bend and straighten, so your triceps do most of the work.
The exercise is quick to learn and needs just two dumbbells and a bench. That makes it a good way to train your triceps directly, at home or in the gym.
Starting position
Sit on the end of the bench with the dumbbells resting on your thighs, then lie back so your head is supported and your feet are planted on the floor.
Hold the dumbbells with your palms facing each other and straighten your arms towards the ceiling so your elbows are directly above your shoulders.
Now bend your elbows and slowly lower the dumbbells as far as you can beside your head. Your upper arms can tilt slightly back towards your head, but your elbows stay roughly above your shoulders. From the bottom, straighten your arms powerfully to full extension, then lower slowly for the next rep.
The three cues
- Elbows roughly above your shoulders
- Lower slowly as far as you can — beside your head
- Straighten powerfully, lower slowly
Common faults
| Fault | How to fix it |
|---|---|
| Your elbows drift towards your feet and it turns into a close-grip press | Keep your elbows over your shoulders. Your upper arms may only tilt slightly towards your head; your elbows do the work. |
| The dumbbells come too close to your head | Lower them beside your head, towards your ears. Go slowly at first until the path is second nature. |
| You only lower partway | Lower as far as you can with control, then straighten all the way. |
| The dumbbells drop | Take your time on the way down and keep the dumbbells under control all the way. |
| Your elbows flare out wide | Keep your elbows about shoulder-width apart, palms facing each other. |
Variations
| Variation | When to use it |
|---|---|
| Light dumbbells | Learn the path beside your head and a slow, controlled lowering. Move on when every rep follows the same path. |
| Full range | Lower as far as you can with control, straighten powerfully to full extension, lower slowly — elbows stay roughly above your shoulders. |
| Heavier dumbbells | Once the full range stays clean on every rep, add weight in small steps. |
Reps and load
Straighten powerfully, lower slowly, through the full range. Choose a weight that lets your upper arms stay steady above your shoulders for every rep.
The exercise fits well at the end of an upper-body session, for example after dumbbell bench presses or push-ups.
Which muscles do the work
| Muscle | Role | What it does here |
|---|---|---|
| Triceps, long head M. triceps brachii, caput longum | Prime mover | Straightens the elbow; the only head that also attaches to the shoulder blade, so it also helps hold the upper arm steady |
| Triceps, lateral head M. triceps brachii, caput laterale | Prime mover | Straightens the elbow |
| Triceps, medial head M. triceps brachii, caput mediale | Prime mover | Straightens the elbow; with the arm raised it carries a large share of the force |
| Rear delts M. deltoideus, pars spinalis | Stabiliser | Help hold the upper arm steady above the shoulder |
| Lats M. latissimus dorsi | Stabiliser | Stops the upper arm tipping back towards the head |
| Forearms Mm. antebrachii | Stabiliser | Grip the dumbbells and keep the wrists straight |
All three heads of the triceps straighten your elbow. The muscles of your shoulder, back and forearm keep your upper arm and wrist steady, so the triceps does the bulk of the work.
Explained in full
Andreas shows the starting position with the elbows above the shoulders, the path down beside the head and the powerful extension — and explains which muscles do the work. · 1:12
Seeing it done right is not the same as doing it right
Video, cues and variations take you a long way. What they cannot give you is an outside eye at the moment the movement isn't quite there yet. That is what training with me is for — in the studio or in a workshop.
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Sources
Alves D, Matta T, Oliveira L. (2018). Effect of shoulder position on triceps brachii heads activity in dumbbell elbow extension exercises. J Sports Med Phys Fitness 58(9):1247–1252. DOI: 10.23736/S0022-4707.17.06849-9 — Compares long- and lateral-head triceps activity in 21 resistance-trained men during overhead and lying dumbbell triceps extensions (40% of maximal isometric strength). In both, activity was higher when straightening than when lowering, and higher at the start and middle of the extension than at the end; both exercises showed similar patterns. The basis for listing the long and lateral heads as prime movers. Medial head not measured, only one or two reps, no figures in the abstract. There is no measurement specific to the Academy's target group (aged 40 to 60, training two to four hours a week). (Evidence type: EMG)
Kholinne E, Zulkarnain RF, Sun YC, Lim S, Chun JM, Jeon IH. (2018). The different role of each head of the triceps brachii muscle in elbow extension. Acta Orthop Traumatol Turc 52(3):201–205. DOI: 10.1016/j.aott.2018.02.005 — Measures all three triceps heads during unloaded elbow extension at five shoulder positions in 10 healthy people (mean age 29) and models their force. With the arm down, the long head produced the most force; from 90 degrees of arm elevation, the medial head did (p < .05). The basis for listing all three heads and for the medial head carrying a large share of the force with the arm raised. A very small sample, no load, force modelled rather than measured. (Evidence type: EMG)
Pedrosa GF, Pereira MR, Kassiano W. (2026). The interplay between muscle length, range of motion, and exercise selection: a review. Sports Med Int Open 10. DOI: 10.1055/a-2733-7605 — A narrative review of muscle length, range of motion and exercise selection. Its key point: training in a lengthened position helps muscle growth mainly when the exercise actually loads the muscle there. The basis for the cue to lower the dumbbells as far as you can control — that is where the triceps is under load at its longest. A review, with no measurement of this exercise itself. (Evidence type: Narrative review)
Schott N, Johnen B, Holfelder B. (2019). Effects of free weights and machine training on muscular strength in high-functioning older adults. Exp Gerontol 122:15–24. DOI: 10.1016/j.exger.2019.03.012 — A 26-week training study in 32 fitness-experienced women and men aged 60 to 86 (mean 66.9): one group trained with free weights, including the lying triceps press, the other on machines, 3 × 10–12 reps twice a week. Triceps strength rose by 89.0% with free weights and 28.3% on machines; the free-weight group rated enjoyment, motivation and everyday benefit higher. The basis for presenting the exercise as easy to learn and practical. A very fit sample, older than the Academy's target group, implement not specified in the abstract. (Evidence type: Intervention study)
A note on context: EMG studies show which muscles an exercise recruits — that is a good reason to pick it, but it does not replace adjusting things to the person in front of you. See a doctor for persistent or severe pain.