The back muscles are attached to the spine. The spine consist of bones called vertebrae. The vertebrae are joined together by the facet joints. Softer disks separate the vertebrae. They allow the spine to bend and flex. They also act as cushion in between the vertebrae and absorb shock and vibration produced by walking and running. Nerves connecting the brain to the body make up the spinal cord.The vertebrae protect the spinal cord. Nerves branch off from the spinal cord to various organs and muscles including those in the arms and legs.The nerves carry instructions from the brain to the muscles, organs, and limbs.They also carry sensations such as pain from different parts of the body to the brain.The spine is joined to the pelvis, or hip, by the sacroiliac joints. The disks in the back act as cushions between vertebrae.A disk contains a central area called the “nucleus pulposus,” which means soft center. Disks are usually moist, like a sponge with water in it.As a person gets older, or after a disk gets injured, it starts losing water and becomes stiffer.The disk becomes less useful in cushioning the back.This is known as disk degeneration. The most common cause of back pain is muscle spasm.An awkward movement of the back can lead to a severe muscle spasm. The muscle spasm causes the back to “lock” and can cause severe pain.A muscle spasm can occur after a simple sneeze or cough. It can also occur after an awkward bending or twisting motion. A movement as simple as bending to tie a shoe or twisting the back to turn and face in a different direction can cause such a spasm. Muscle spasms can also occur when a heavy object is lifted incorrectly. Muscle spasms tend to get better over time.Severe cases of muscle spasm can be treated with physical therapy and medication.Long lasting back pain can occur after accidents that have resulted in injury to the disks, the facet joints, or sacroiliac joints of the back. Back pain is one of the most common medical problems. It affects most people at least once in their lifetime. If not taken seriously, back pain can last for a long period of time, and can become disabling. The best way to prevent back and leg pain is to regularly exercise the back.Back strengthening and stretching exercises are recommended at least 2 or 3 times a week. The following are some examples of back exercises: partial sit-up (With bent knee, slowly raise your head and shoulders off the floor, and hold for 3 minutes), knee-to-chest raise (lie down;slowly pull knees to chest, relaxing your neck and back, hold for 10 seconds;repeat 10 times), press-up (lie down with hands near shoulders and pelvis on floor;press up painlessly, hold for 10 seconds, and repeat 10 times). These exercises strengthen the back muscles, which allow them to withstand the rigors of everyday activities.If you have had previous back pain or medical problems, make sure to check with your doctor before starting these exercises. Back pain will affect most people at one time in their lives.Action can be taken to prevent back pain or postpone the degeneration of the spine and disks. Preventive measures include strengthening of the back and adopting good body techniques.