An effective exercise for building strength in the upper back, the barbell row primarily targets the latissimus dorsi and trapezius muscles. Using a barbell to train your back -- rather than a pulley cable, for example -- means your back muscles have to move the entirety of the weight rather than relying on momentum, the result of which can be greater strength and development.
Lats and Traps
The large fanlike muscles that lie on both sides of your back are the latissimus dorsi, or the lats. Running from your lower back to the upper arm bone, the lats help to stabilize your back and move your arms. The trapezius muscles reside above the lats in the upper center of your back. Barbell rows primarily work the lower traps, which help to support your shoulders and arms.
Focus on Form
Barbell rows must be performed correctly to maximize the results. Take hold of a barbell with an overhand grip that is slightly wider than shoulder-width. Stand with your feet shoulder-width apart and bend your knees to 15 degrees. Pull your abdominal muscles in and slide your shoulder blades down your back. Lean your torso forward by approximately 60 degrees. Pull the barbell toward your stomach as your elbows extend behind you. Straighten your arms to return to starting position.