Sit on a pull-down machine with attached wide bar. Adjust the seat height and the knee pad to fit your height. The knee pad is needed to prevent your body from being raised when performing the exercise.
Grab the bar with the fingers facing forward. Grip width should be wider than shoulder width.
Holding the bar, bring your torso back around 30 degrees while creating a curvature on your lower back and sticking your chest out. This is your starting position.
Bring the bar down until it touches your lower chest. Concentrate on back muscles contraction at the bottom point of the movement. The upper torso should remain stationary and only the arms should move. The forearms should do no other work except for holding the bar; therefore do not try to pull down the bar using the forearms.
After a second at the contracted position, slowly return the bar back to the starting position when your arms are fully extended and the widest back muscles are fully stretched. Inhale during this movement.