Seated with a slight backwards lean, take a slightly wider than shoulder-width grip on a straight bar attached to an upper pulley. Make sure your palms are facing away from your body. Keeping your shoulder blades slightly pinched and core tight, pull down on the bar until the bar passes your chin. Be sure to lead with the elbows and use your back to pull down on the bar. Make sure not to overly-lean back as this will work a different muscle group of your back. Then control the weight back up to the starting position.

(Note: These images were taken to demonstrate proper form and technique. The straight bar in these pictures was not attached to an upper pulley in order to better demonstrate the exercise. Be sure to use a straight bar attached to an upper-pulley to perform this lift.)