One of the possible remedies for low back pain is moderate exercise that focuses on strengthening the muscles of the back, legs and stomach.

Knowing the suspected cause of your low back pain might help in deciding which exercises might benefit you. Be aware that some causes of low back pain require prompt medical evaluation and treatment, rather than exercise alone. Causes that require prompt attention include inflammatory arthritis of the lower back, cancer, bacterial infections of the bones or disks and organ-related pain (from kidney stones to fibroids to inflammation of the intestines). For most people with low back pain, however, no definitive cause is ever found, says Robert Shmerling, M.D., associate physician at Beth Israel Deaconess Hospital and associate professor at Harvard Medical School.

The tricky thing about low back pain is that it can get better completely without medical treatment or it may stubbornly resist treatment and persist for years. Although most people improve, low back pain returns in about 40 percent of cases, Dr. Shmerling says. "We often don't know if it's going to get better quickly or last a long time," he adds.

Certain exercises can be a way to reduce the chance that pain will return and to manage ongoing pain, he says. In some cases, just doing the routines can prevent a recurrence.

Here are some exercises commonly recommended by Dr. Shmerling and other physicians. Before starting these routines, check with your doctor. Specifically, ask how many times a week you should perform the exercises.

If your muscles are tight, take a warm shower or bath before performing any of these exercises. Wear loose clothing and use a rug or mat. Do not wear shoes.

Stop and consult with your doctor if you feel any discomfort, if your back pain increases or if any tingling, numbness or weakness occurs in your legs.

Single knee-to-chest stretch. The purpose of the single knee-to-chest stretch is to stretch the lower back and hamstrings and strengthen the stomach and hip-flexing muscles.

Double knee-to-chest stretch. The purpose of the double knee-to-chest stretch is to stretch the lower back and hamstring muscles and relieve pressure on bone facets, where vertebrae come together.

Pelvic lift. The purpose of the pelvic lift is to strengthen the gluteal (buttocks) and abdominal muscles and flatten the spine.

Pelvic tilt. The purpose of the pelvic tilt is to gently move the spine and stretch the lower back.

Hamstring stretch. The purpose of the hamstring stretch is to strengthen the gluteal (buttocks) and abdominal muscles and flatten the spine.

Hamstring stretch while standing. The purpose of this exercise is to strengthen the gluteal (buttocks) and abdominal muscles and flatten the spine.

Lower trunk rotation stretch. The purpose of the lower trunk rotation stretch is to stretch the hips and the rotator muscles of the lower and midback and stretch the ligaments that support your disks.

Alternate leg extension. The purpose of the alternate leg extension is to strengthens your gluteal (buttocks) and abdominal muscles and flatten the spine.

Lumbar extension. The purpose of the lumbar extension is to extend the muscles in your lower back.

Side stretch. The purpose of the side stretch is to stretch and strengthen your back and supporting muscles.

Chair stretch. The purpose of this exercise is to stretch and strengthen your back and supporting muscle. Do not do this exercise if you have osteoporosis.

Leg lift. The leg lift is a strengthening exercise.

Extension: press-ups. The purpose of this exercise is to strengthen your lower back muscles and stretch your stomach muscles and ligaments.

Many exercises actually increase your risk of low back pain. Because of this, you should avoid the following: