A sprain is a stretch and/or tear of a ligament, the fibrous band of connective tissue that joins the end of one bone to another. Ligaments stabilize and support the body’s joints. A sprain is caused by direct or indirect trauma (a fall, a blow to the body, etc.) that knocks a joint out of position, and overstretches, and in severe cases, ruptures the supporting ligaments. Typically this injury occurs when an individual lands on an outstretched arm, slides into a base, jumps up and lands on the side of the foot, or runs on an uneven surface.
A strain is an injury of the muscle and/or tendon. Tendons are fibrous cords of tissue that attach muscles to bone. Chronic strains are the result of overuse (prolonged, repetitive movement) of muscles and tendons. Inadequate rest breaks during intensive training precipitates a strain. Acute strains are caused by a direct blow to the body, overstretching, or excessive muscle contraction. In most cases the mechanism of injury resulting in a sprain or a strain may be the same, it’s just a matter of which tissues are damaged in the injury.

Lumbar sprains and strains result from injury to the soft tissues of the lower back. Most lumbar sprains and strains are caused by heavy lifting, twisting motions, involvement in sports, poor posture or body mechanics, car accidents, and falls. Sprains result from overstretched ligaments in the low back and strains are caused by overuse of a muscle or overstretching the muscles of the low back.