Sit down on a pull-down machine with a V-Bar attached to the top pulley.
Adjust the knee pad of the machine to fit your height. These pads will prevent your body from being raised by the resistance attached to the bar.
Grab the V-bar with the palms facing each other (a neutral grip). Stick your chest out and lean yourself back slightly (around 30-degrees) in order to better engage the lats. This will be your starting position.
Using your lats, pull the bar down as you squeeze your shoulder blades. Continue until your chest nearly touches the V-bar. Exhale as you execute this motion. Tip: Keep the torso stationary throughout the movement.
After a second hold on the contracted position, slowly bring the bar back to the starting position as you breathe in.
Repeat for the prescribed number of repetitions.
Caution: Avoid the temptation to use a weight so big that you need to start swinging your torso in order to perform the exercise.