Barbell seated close-grip concentration curl

Sit on a bench with your feet flat on the floor and hold a barbell with an underhand grip, hands shoulder-width apart. Rest your upper arms against your inner thighs, just above your knees, and let the barbell hang down in front of you. Keeping your upper arms stationary, exhale and curl the barbell up towards your shoulders, contracting your biceps. Hold the contracted position for a brief pause, then inhale and slowly lower the barbell back down to the starting position. Repeat for the desired number of repetitions.