STARTING POSITION:
Select the appropriate resistance in the weight stack. There should be a handle that is attached to a high pulley. Grab it with your right hand and sit on a fitball with your left shoulder pointing to the pulley. Your arm should start crossed and in front of your face. Contract your pelvic floor and core while keeping your chest up.
MOVEMENT:
Pull the handle towards your right hip and the floor until your arm is fully extended while you exhale. Return to the starting position in a smooth movement while you inhale. Repeat the movement for the specified amount of repetitions and then repeat with the other arm.
TIPS: The exercise key is quality over quantity. The trick is to perform the exercise using proper form. While your are doing the exercise, move only the shoulder joint, make sure you don't move any other part of your body.