Hamstring Muscle Injuries
Hamstring muscle injuries — such as a “pulled hamstring” — occur frequently in athletes. They are especially common in athletes who participate in sports that require sprinting, such as track, soccer, and basketball.
A pulled hamstring or strain is an injury to one or more of the muscles at the back of the thigh. Most hamstring injuries respond well to simple, nonsurgical treatments.
A hamstring injury can be a pull, a partial tear, or a complete tear. Muscle strains are graded according to their severity. A grade 1 strain is mild and usually heals readily; a grade 3 strain is a complete tear of the muscle that may take months to heal. Most hamstring injuries occur in the thick part of the muscle or where the muscle fibers join tendon fibers. In the most severe hamstring injuries, the tendon tears completely away from the bone. It may even pull a piece of bone away with it. This is called an avulsion injury.
Common Cause: Muscle Overload
Muscle overload is the main cause of hamstring muscle strain. This can happen when the muscle is stretched beyond its capacity or challenged with a sudden load. Hamstring muscle strains often occur when the muscle lengthens as it contracts, or shortens. Although it sounds contradictory, this happens when you extend a muscle while it is weighted, or loaded. This is called an “eccentric contraction.”
During sprinting, the hamstring muscles contract eccentrically as the back leg is straightened and the toes are used to push off and move forward. The hamstring muscles are not only lengthened at this point in the stride, but they are also loaded — with body weight as well as the force required for forward motion. Like strains, hamstring tendon avulsions are also caused by large, sudden loads.
What Are Symptoms Of A Hamstring Tear?
A hamstring injury typically causes a sudden, sharp pain in the back of your thigh. You might also feel a popping or tearing sensation. Swelling and tenderness usually develop within a few hours. You may also experience bruising or discoloration along the back of your leg, as well as muscle weakness or an inability to put weight on your injured leg.
Mild hamstring strains can be treated at home. But you should see a doctor if you can’t bear any weight on your injured leg or if you can’t walk more than four steps without significant pain.