Doing bicep curls on an incline bench builds more muscle in the upper part of your biceps than preacher curls do.

Doing bicep curls on an incline bench might build your biceps muscle better than doing preacher curls, especially in the middle part of your upper arm.

Different bicep curl exercises lead to different patterns of muscle growth: incline curls cause more growth near the shoulder end of the biceps, while preacher curls cause more growth in the brachialis and brachioradialis muscles along the forearm side of the upper arm.

When performed by the same person, incline curls lead to more growth in the main bicep muscle, while preacher curls lead to more growth in the forearm muscles that help bend the elbow.

When performing incline dumbbell curls, the upper part of the biceps and related elbow flexor muscles tends to grow thicker than when performing preacher curls. Conversely, preacher curls tend to produce greater thickening in the lower part of these muscles.

Whether you use a cable machine or a barbell to do preacher curls for 10 weeks, your biceps will grow about the same amount — the exact way you apply resistance doesn’t matter much for muscle size.