The hamstrings are a group of muscles found at the back of the thigh. Three muscles are in this group: the biceps femoris, the semitendinosus and the semimembranosus. The function of these muscles is to bend the knee and to extend the hip. It is common for these muscles to become hyperextended and injured.
Hamstring hyperextension is often associated with sports, including track and field (particularly sprinting and hurdles), tennis, basketball, rugby and football. Ballet and gymnastics are also prime activities for causing hamstring hyperextension. For hamstring hyperextension to occur, the leg is raised, and the foot is moved away from the body while the knee is bent, usually in a quick movement or sudden change in direction. Hamstring hyperextension is often caused by tight hamstrings or an imbalance in muscle strength as the hamstrings are generally much weaker than the quadriceps, which reside in the front of the thigh. The best way to avoid hamstring hyperextension is to ensure the muscles are warmed up and stretched adequately prior to activity.
Hamstring hyperextension results in pulled hamstrings. Symptoms of hamstring hyperextension include hamstring pain, muscle stiffness, swelling, bruising and a palpable mass. When the injury happens there will be a sudden sharp pain in the hamstrings, and the knee may not be able to extend past 30 to 40 degrees. The severity of the injury will dictate level of pain, range of motion and walking ability.
Hamstring hyperextension is usually diagnosed by means of a physical examination. This is performed by doing a palpation of the muscles to determine if there are tender or painful areas. The therapist or doctor may also have the patient do a straight leg raise, a resisted knee flexion and a slump test, all of which are used to assess hamstring tightness and level of pain. In addition to these tests, the therapist or doctor will get a patient's medical history, history of injury and the details of the current injury.
Treatment for hamstring hyperextension must begin immediately. The first 48 hours are the most crucial for treatment. RICE is used -- rest, ice, compression and elevation. The pain and swelling associated with hamstring hyperextension are treated with rest and ice, and a compression bandage can be used to minimize intramuscular bleeding. Excessive pain and swelling may be treated with non-steroidal anti-inflammatory drugs NSAIDs. Once pain diminishes, range of motion and strengthening exercises should be introduced to regain use of the hamstrings. Physical therapy may also be required to ensure a full recovery.