The dumbbell preacher curl trades the bar for a single dumbbell, performed one arm at a time on a preacher bench. The dumbbell allows independent loading of each arm, fixes side-to-side imbalances, and lets the working biceps move through a slightly deeper supinated range than barbell preacher curls.
What it is
The dumbbell preacher curl is a preacher curl performed with a dumbbell, one arm at a time. The upper arm rests on the preacher bench pad, isolating the biceps in flexion. The dumbbell allows full supination throughout and fixes the left/right imbalance that the bilateral barbell version can hide.
Muscles worked
| Muscle | Contribution |
|---|---|
| Biceps brachii | ~70 % |
| Brachialis | ~20 % |
| Forearms | ~10 % |
How to dumbbell preacher curl: 5 steps
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Set up the preacher
**Sit at the preacher bench.** Upper arm rests fully on the pad.
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Position the dumbbell
**Grip a dumbbell supinated** in the working hand, opposite hand braced on the pad.
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Lower to stretch
**Allow the arm to extend nearly fully** (slight bend retained to keep tension).
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Curl up
**Curl strict, elbow stays on the pad** — no cheating.
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Peak and descent
**Squeeze at the top, then lower over 2-3 seconds.** Complete reps, switch arms.
How it differs from preacher curl
- One arm at a time. Bilateral barbell preacher curl hides imbalances; dumbbell version exposes them.
- Free rotation. The dumbbell allows supination at the top — barbell is fixed.
- Lighter loads. A single arm handles 60-70 % of bilateral barbell preacher curl weight.
- Better mind-muscle connection. Single-arm focus often improves biceps activation.
Common mistakes
When to use this variation
Use dumbbell preacher curls to fix biceps imbalances, add focused unilateral hypertrophy, or to feel the contraction better than bilateral barbell variants allow. Program 3 sets of 8-12 reps per arm. Pair as the second biceps exercise in a session, after compound bar curls.
FAQ
Bench angle?
The standard preacher pad is angled at about 30-45° from vertical. That’s the standard setup — no adjustment needed.
How heavy a dumbbell?
For a 75 kg intermediate male: 10-16 kg per arm for clean 10-rep sets. Lighter than standing dumbbell curls because the strict position eliminates body english.
Dumbbell or barbell?
Barbell loads heavier and is faster. Dumbbell isolates each arm. Use both — alternate between sessions or include both in arm specialisation phases.
Related exercises
- Preacher Curl: bilateral barbell version
- Concentration Curl: another isolated single-arm curl
- Dumbbell Curl: standing dumbbell version
- Spider Curl: chest-supported variant
