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.

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

For guys new to lifting, doing bicep curls with your arms in front of your body works just as well for building arm muscle as doing them with your arms behind you — both give about the same 6% to 9% growth in 10 weeks.

For young women doing strength training twice a week, preacher curls might build more muscle in the lower part of the biceps than incline curls.

Whether you do preacher curls with a cable machine (harder when your arm is bent) or a barbell (harder when your arm is straight), your biceps grow about the same amount after 10 weeks of training.

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.