One Arm Shoulder Press
The one arm shoulder press is a unilateral dumbbell exercise targeting the deltoids and triceps. Pressing with one arm at a time requires significant core stabilization to resist lateral lean, making it effective for addressing shoulder strength imbalances.
How to do it
- Stand or sit with a dumbbell in one hand, raised to shoulder height with your palm facing forward.
- Brace your core to stabilize your torso against the unilateral load.
- Press the dumbbell straight overhead until your arm is fully extended.
- Pause at the top, then slowly lower the dumbbell back to shoulder height.
- Complete the desired repetitions on one side before switching arms.
Form cues
- Keep your ribs pulled down and core braced tight.
- Press the dumbbell straight up, avoiding a wide arc.
- Keep your palm facing forward or slightly inward.
- Control the weight all the way back down to shoulder height.
Breathing: Inhale as you lower the dumbbell to your shoulder, and exhale steadily as you press it overhead.
Common mistakes
- Leaning to the side - leaning away from the weight reduces core engagement and places unnecessary stress on the spine.
- Using momentum - bouncing from the knees takes the work away from the shoulder and delts.
- Flaring the elbow too far forward - keeping the elbow directly under the wrist protects the shoulder joint.
Muscles worked
Primary: delts. Secondary: triceps, traps, core.
Suggested sets & reps
Get fitter
3 sets × 8–12 reps per side, rest 60 s
Lose weight
3 sets × 10–12 reps per side, rest 60 s
Build muscle
3–4 sets × 8–10 reps per side, rest 90 s
Easier, harder & alternatives
Make it harder
Take care if…
- If you feel sharp shoulder pain during the press, ease off and choose a gentler movement.
General educational guidance, not medical advice. Stop on sharp pain and check with a qualified professional if unsure.
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Start free →Frequently asked questions
Why should I press with one arm instead of two?
Unilateral pressing forces your core to work harder to keep your torso stable and helps prevent muscle imbalances between your left and right sides.
Should I stand or sit while doing this exercise?
Standing challenges your balance and core more, while sitting provides extra back support, making it easier to focus purely on the shoulder muscles.
What should I do if I feel lower back strain?
Lower back strain usually means your core is relaxed or you are arching your back to help lift the weight. Lighten the load and brace your abs harder.