Brace the upper arms on a preacher bench or glute ham bench holding an EZ curl or straight bar with a pronated grip. Keeping the arms supported on the bench, curl the bar up and return to the bottom under control.
 
Purpose
The preacher curl enforces strict curling to maximize bicep focus, and changes the resistance curve relative to a standing curl. The reverse grip emphasizes the brachioradialis and brachialis.
 
Programming
Generally sets of 10-20 reps are appropriate.