Set up a cable station with a straight bar attached to the bottom of the pulley. Stand at the cable station with your feet shoulder width apart and with a slight bend at the knee. Grip the straight bar in both hands with an underhand grip. Keeping your core braced and your elbows fixed at your sides pull the bar towards the top of your chest, moving your forearms only and exhaling as you do so. Squeeze your biceps at the top of the movement, and then slowly lower the bar back to the starting position, inhaling as you do so.