Loop a band around the middle of a barbell. Stand on the opposite end of the band. Grasp the barbell in both hands about shoulder width apart. Contract the biceps muscle and curl the bar up toward your chest. The band overloads the top portion of the lift and increases the difficulty at the easiest portion of the lift.
Resistance Band Barbell Curls Exercise - Start Position
Resistance Band Barbell Curls Exercise - Finish Position