Lateral Pull Down
Sit on the lateral pull down machine, knees under the pads. Take an overhand grip wider than shoulder width. Exhale when you pull the bar down, inhale as you bring it back up.
Lateral pull down is a great compound exercise for both developing the width, as well as the bulk of your back. To reap the greatest rewards from this exercise you need to go through the full range of motion. This means in a relaxed state your hands should be fully extended without actually locking out your elbows. Locking elbows could lead to tendonitis. On contraction the bar should go as far down as possible to achieve peak flexion of latissimus dorsi (upper back muscles). You can take the grip anywhere wider than shoulder length but within twice the shoulder length. The width of the grip will determine how you will bring the bar down and subsequently the exercise's focus. A grip just wider than your shoulders will require you to bring your elbows directly down in a straight line with your torso. You will bring the bar down to either your chin or the back of your head. This variation is good for developing the width of the back by invoking the lateral fibers. Taking the grip at twice your shoulder length will require you to bring the bar down to your upper chest and bringing your elbows back. This concentrates on the middle and upper fibers of your back. The wider the grip the less you are advised to bring the bar behind your back and to your neck. This forces and unnatural rotation of your shoulder and will cause injury.
Performing lateral pull downs behind your back is generally easier and a good place to start with low weight. Note that in performing this exercise you will always use the overhand grip. Ensure that you adjust the pad/seat in such a way so that it firmly holds you in place with your feet flat on the floor. Keep your chest out and your back straight throughout the exercise (especially your lower back). Control the movement from top to bottom.