Adjust the lap-bar so that your body stays firmly in place throughout the exercise. Using a shoulder-width grip and palms facing in, extend your arms fully so that you feel a full stretch in your lats. With a slight arch in your back, pull the bar towards your lower chest, squeeze your lats briefly and then return the bar to the starting position.
Instead of keeping your back completely rigid and straight, allow yourself to move naturally throughout the exercise. It is okay to lean back anywhere from 45-55 degrees as you pull the weight down.
Reverse-Grip Lat Pulldowns Back Exercise - Start Position
Reverse-Grip Lat Pulldowns Back Exercise - Finish Position