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Alternate Biceps Curls

Alternate bicep curls work one arm at a time with dumbbells, letting you focus fully on each rep and stopping your stronger arm from quietly carrying the weaker one. They are a staple for beginners learning strict curl mechanics and for anyone fixing a left-right size gap. Coached by Maddy (NASM-CPT) — these are the exact form cues he gives on every client's first week.

Muscles worked

Biceps · biceps brachii Brachialis Forearms · brachioradialis Forearm flexors

Sets & reps by goal

Goal	Sets × Reps	Rest
Strength	4 × 4–6 per arm	2 min
Muscle	3–4 × 9–12 per arm	60–90 s
Endurance	2–3 × 18–27 per arm	45–60 s

Rep ranges per Helms 2014 · Schoenfeld 2016.

Level — Beginner

Beginner-friendly — the discipline is keeping the resting arm truly still.

Proper form — 5 cues

Curl one dumbbell while the other hangs completely still at your side.
Turn your palm up as the weight rises so it faces the ceiling at the top.
Pin the working elbow to your ribs — it should not drift forward or back.
Lower for a slow 3 seconds until the arm is fully straight before the other side starts.
Stand with a soft knee bend and squeeze your glutes so your hips cannot swing.

Breathing: Exhale as you curl the weight up, inhale as you lower it under control.

The 3 mistakes Maddy corrects most

Both arms moving at once in a rush. It becomes a see-saw of momentum and neither bicep gets a clean contraction. Fix: One rep finishes completely — arm straight — before the next arm begins.

Swinging the hips to throw the weight up. The lower back generates the force and the bicep only catches the finish. Fix: Drop the weight, brace your midsection, and keep your torso statue-still.

Stopping halfway down. The lengthened bottom half is where much of the growth stimulus lives. Fix: Straighten the elbow fully at the bottom of every single rep.

Common questions

Alternate curls or both arms together — which is better?

Alternating gives each arm your full attention and exposes a strength gap between sides; curling both together is more time-efficient and slightly harder on the core since both weights load you at once. Many good programs rotate between the two. If one arm is visibly behind, alternate — and start every set with the weaker side.

Can beginners do alternate bicep curls?

Yes — this is one of the best first dumbbell exercises there is. The pattern is simple, the load starts light, and alternating gives you a built-in pause to check your form between reps. Begin with a weight you can curl 12 times per arm with a still torso, and progress from there.

Why alternate the arms at all?

Two reasons: focus and honesty. With one arm working, you can direct everything at a single clean contraction instead of splitting attention. And because each arm lifts alone, your dominant side cannot mask a weaker one — a gap that stays hidden with barbell curls shows up immediately here.

Related exercises

Alternate Hammer CurlForearms · Biceps Biceps CurlsBiceps Hammer CurlForearms · Biceps Single Hand Biceps CurlBiceps Single Hand Biceps CurlsBiceps

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