STARTING POSITION:
Select the appropriate resistance in the weight stack. There should be a cable bar that is attached to the lowest level of a pulley. Grab it with your hands using a prone grip. Sit down on a bench and lift the bar with both hands just above of you by extending your arms. Contract your pelvic floor and core while keeping your chest up.
MOVEMENT:
Slowly lower the dumbbell just behind you bending your arms while you inhale. Return to the starting position in a strong movement while you exhale.
TIPS: While your are doing the exercise, move only the elbow joint, make sure you don't move any other part of your body.