Single Arm Supinated Grip Dumbbell Lying Triceps Extension
In SetGrip: Dumbbell Lying Triceps Extension (Single Arm, Supinated Grip)
- Secondary muscles
- Forearms
- Body part
- Upper Arms
- Position
- Lying
- Laterality
- Unilateral (one arm at a time)
- Category
- Strength
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With an underhand grip, the lying single-arm extension asks your fingers to keep the dumbbell from rolling out of your palm as it drops behind your head, which is why forearms show up as the secondary muscle. Most lifters find the elbow tracks tighter to the body here than in the pronated-grip twin, at the same light load.
How to do the Single Arm Supinated Grip Dumbbell Lying Triceps Extension
- Lie flat on a bench with your back and head supported, and your feet flat on the ground.
- Hold a dumbbell in one hand with an underhand grip, and extend your arm straight up above your shoulder.
- Keeping your upper arm stationary, slowly lower the dumbbell behind your head by bending your elbow.
- Pause for a moment at the bottom, then extend your arm back up to the starting position.
- Repeat for the desired number of repetitions, then switch arms.
Tip: Keep a slight bend at the top on lying extensions to protect the elbow, but lock out fully on cable pushdowns.
Muscles worked
Primary
Triceps · Arms
The triceps straighten the elbow, and overhead variations stretch the long head at the bottom, so you should feel the whole back of the upper arm working with a hard squeeze at lockout.
Secondary
- Forearms — The forearms grip and stabilize the wrist, which should stay straight rather than bending back under the load.
Common mistakes
- Elbows flaring out — on overhead and lying extensions the elbows should stay pointed forward or up, not out to the sides, since flaring turns it into a press.
- Upper arm moving — the upper arm should be pinned in place and only the forearm should move; if the elbow drifts, drop the weight.
- Not finishing the rep — take every rep to a full triceps squeeze; on pushdowns that means a complete lockout for a count.
- Cutting the stretch — on overhead extensions let the weight travel down behind the head until you feel the long head stretch before pressing up.
Sets, reps and where it fits
| Goal | Sets × reps | Rest |
|---|---|---|
| Muscle growth | 3–4 × 10–15 per side | 60–90 s |
| Endurance / finisher | 2–3 × 15–20 per side | 45 s |
| Strength | Not ideal — pick a compound lift for the same muscle | — |
Triceps extensions go after the presses in a push session or at the end of an arm day. Superset them with biceps curls on the same cable stack or with the same dumbbells.
Variations and alternatives
Similar exercises
Without dumbbell
Frequently asked questions
What muscles does the Single Arm Supinated Grip Dumbbell Lying Triceps Extension work?
The Single Arm Supinated Grip Dumbbell Lying Triceps Extension primarily works the triceps. It also involves the forearms, which assist the movement and stabilise the joints.
Is the Single Arm Supinated Grip Dumbbell Lying Triceps Extension good for beginners?
It is rated intermediate, so it suits people who already train regularly. Beginners can still do the Single Arm Supinated Grip Dumbbell Lying Triceps Extension with light load and a spotter or coach watching the first few sessions; if it feels awkward, pick an easier variation from the alternatives below first.
What can I do instead of the Single Arm Supinated Grip Dumbbell Lying Triceps Extension?
If you cannot do the Single Arm Supinated Grip Dumbbell Lying Triceps Extension, try the Reverse Grip Arm Blaster Cable Triceps Pushdown, the Pronated Grip Dumbbell Skull Crusher or the Reverse Grip Barbell Skull Crusher. Each of them trains the triceps through a similar movement, so you can swap them in without changing the rest of the workout.
How many sets and reps should I do?
It depends on your goal. For the Single Arm Supinated Grip Dumbbell Lying Triceps Extension, a sensible starting point is muscle growth: 3–4 × 10–15 per side with 60–90 s rest; endurance / finisher: 2–3 × 15–20 per side with 45 s rest. Do it after your compound lifts. It is a finishing movement, not the main event.
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Exercise data and animations are licensed ExerciseDB content used in SetGrip. This page is for general information and is not medical or coaching advice.