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Single Hand Biceps Curls

Single-hand biceps curls alternate arms rep by rep — one dumbbell curls while the other arm rests at your side, trading places in a steady rhythm. The built-in micro-rest lets each biceps recover a beat between efforts, so you can hold crisp form deeper into the set than curling both arms together. 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 × 3–6 per arm, alternating	2–3 min
Muscle	3–4 × 9–12 per arm, alternating	60–90 s
Endurance	3 × 18–27 per arm, alternating	45–60 s

Rep ranges per Helms 2014 · Schoenfeld 2016.

Level — Beginner

Beginner-friendly — the alternating rhythm builds in recovery, making it the most forgiving curl format.

Proper form — 5 cues

Hold one dumbbell, or one in each hand with only one moving at a time
Curl the working arm while the resting arm hangs completely still
Rotate the palm up as the dumbbell passes your thigh
Alternate arms in an even left-right rhythm — no double reps on one side
Keep both shoulders level; do not dip toward the curling arm

Breathing: Exhale as each dumbbell curls up, inhale as it lowers — one full breath per arm.

The 3 mistakes Maddy corrects most

The resting arm swinging as a counterweight. The idle arm's swing rocks the torso and feeds momentum into the working curl, quietly cheating every rep. Fix: Press the resting hand lightly against your thigh so stillness on one side becomes automatic.

Shoulders see-sawing with each alternation. Dipping toward the working side turns the curl into a side-bend and loads the waist instead of the arm. Fix: Fix your collarbones level like a shelf, and let only the forearms move beneath them.

Racing the rhythm so both arms blur together. When reps overlap, the micro-rest disappears and form decays on both sides at once. Fix: Finish each curl completely — arm fully lowered — before the other side begins.

Common questions

Alternating curls vs curling both arms at once — which builds more muscle?

Muscle growth follows the quality and quantity of hard sets, and both styles can deliver it. Alternating gives each arm a short rest every rep, so form survives longer and each rep gets full attention; simultaneous curls finish faster and load the trunk more. Pick by preference and rotate occasionally.

Why rotate my palm during the curl?

The biceps does two jobs — bending the elbow and turning the palm upward. Starting neutral at your side and rotating to palm-up as you curl lets the muscle perform both roles in one rep, which many lifters find gives a stronger contraction than keeping the wrist fixed throughout.

How many alternating curls make a good set?

Count per arm, not total swings. Nine to twelve quality reps per arm suits muscle-building; the alternating format means such a set takes a while, which is part of its value. Stop when the torso starts helping — extra swung reps train momentum, not biceps.

Related exercises

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

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