Edward R. Laskowski, M.D.: The bent-over row is an exercise you can do with dumbbells to work the muscles in the back of the shoulder. The bent-over row targets the posterior part of the deltoid in the shoulder. That's important, because many people focus on the muscles at the front of the shoulder. What you really want is balance in the shoulder muscles.
Nicole L. Campbell: To do the bent-over row with a dumbbell, hold a dumbbell in your hand and stand with your feet comfortably apart. For most people, this is about shoulder-width apart. Tighten your abdominal muscles. Bend your knees and lean forward at the hips, keeping your spine nice and straight. Let your arms hang straight below your shoulders and slowly raise the weight until your elbow lines up just below your shoulder and parallel with your spine. Then slowly lower the weight to the starting position. You'll feel tension in the back of your shoulder and the muscles across your upper back.
When doing the bent-over row, do not allow your shoulder to roll forward.
For most people, one set of 12 to 15 repetitions is adequate.
Remember, for best results, don't allow your shoulder to roll forward during the exercise. Hold your shoulder as stationary as possible, keeping your spine neutral, your abdominal muscles tight, and your movements smooth and controlled.