Single-Arm Dumbbell Preacher Curl

What is the Single-Arm Dumbbell Preacher Curl?

The single-arm dumbbell preacher curl braces one upper arm on a preacher pad and curls a dumbbell through a strict range. Working one arm at a time exposes and evens out side-to-side differences a barbell can hide, while the pad removes momentum entirely for a hard, isolated contraction from the stretched bottom.

Muscles worked

Primary: Biceps

The biceps flexes the elbow while the pad holds the upper arm fixed, forcing a strict single-arm contraction that’s hardest at the stretched bottom of the range.

How to perform the Single-Arm Dumbbell Preacher Curl

1. Set up at a preacher bench with a single dumbbell and lay one upper arm flat along the angled pad, armpit high on the edge.
2. Working one arm at a time exposes side-to-side strength differences that a two-arm bar can hide.
3. Let the dumbbell hang with a supinated grip and the elbow nearly straight against the pad at the bottom.
4. Curl the dumbbell up by flexing the elbow, keeping the back of the upper arm glued to the pad.
5. Supinate fully and squeeze at the top without letting the elbow lift off the pad.
6. Lower under control and avoid snapping the elbow into a hard lockout at the stretched bottom.

Suggested working range: 10–15 reps. Default progression: double progression.

Mechanics

A single-joint isolation performed one arm at a time against a preacher pad: elbow flexion with the back of the upper arm supported so the shoulder can’t move. Loading one arm with a dumbbell means the weaker side can no longer lean on a stronger one.

Form cues

• •Brace one upper arm flat on the pad with the armpit at the top edge.
• •Curl the dumbbell by flexing only the elbow, supinating the wrist as you rise.
• •Lower to a near-full extension under control, and don’t drop out of the stretch.
• •Keep your chest off the top of the pad rather than leaning in to cheat.

Common mistakes

• •Snapping the elbow into a hard lockout at the stretched bottom, straining the tendon.
• •Lifting the back of the upper arm off the pad to recruit the shoulder.
• •Failing to supinate at the top so the biceps never fully shortens.
• •Dropping the dumbbell quickly instead of controlling the descent.

Variations & alternatives

• •Barbell or EZ-bar preacher curl, both arms on one bar for heavier loading.
• •Machine preacher curl, a fixed path for a controlled, safe contraction.
• •Concentration curl, another strict single-arm peak-contraction curl.
• •Cable preacher curl, constant tension across the braced range.

Barbell Curl

Biceps · Barbell

Dumbbell Curl

Biceps · Dumbbell

Hammer Curl

Biceps · Dumbbell

Cable Curl

Biceps · Cable

Incline Dumbbell Curl

Biceps · Dumbbell

Programming: sets, reps & when to use it

Program the single-arm dumbbell preacher curl in the library’s 10–15 rep range as a strict biceps accessory, letting the weaker arm set the load. Control the lowering and never bounce out of the stretched bottom. A couple of sets per arm after your heavier curls evens out imbalances and finishes the biceps.

Frequently asked questions