Your back is made up of three major muscle groups. The latissimus dorsi is located on each side of your back and helps you extend, rotate, and pull your arms toward your body. The erector spinae (lower back) is made up of three muscles that run the length of your back from your neck to your fanny. The erector spinae is involved in flexion and extension of the upper body, as well as rotation. The rhomboids (major and minor) are between the shoulder blades and aid in rotation, elevation and retraction of the shoulder blades. These are also known as your 'posture' muscles.

Why Should You Work Your Back?

Your back muscles are involved in just about every activity you do each day, so it is important that they're strong enough to handle all that work. Strength training your back muscles will also add muscle mass to your upper body, which can help make your waist look smaller. Like your chest, your back is made up of big muscles that can handle heavy weight and, therefore, help you burn more calories.

How Often Should You Train Your Back?

Like all muscles in your body, you can perform back exercises up to three non-consecutive days a week. If you're lifting heavy weights, (enough that you can only complete six to eight repetitions) you'll need two or more days of rest before you perform the exercise again. For this reason, you might only work your back once or twice a week. If you're goal is endurance and strength, stick with one to three sets of 8-15 repetitions, and at least one day of rest before you perform the exercises again.

What Exercises Should You Do?

Most back exercises involve some type of rowing motion such as the seated row, dumbbell row and rear delt row. Other popular exercises include lat pulldowns, back extension and reverse flies. Choose a mixture of different exercises to target your back from a variety of directions and make sure you vary your routine every 4-6 weeks to avoid plateaus.Remember, don't neglect your other muscle groups.