Leg > Hamstring Strain

What are the Hamstring Muscles?

Hamstring is the common term for the three muscles (semitendinosus, semimembranosus, and biceps femoris) that run along the back of your thigh. Tendons, also called hamstrings, attach thigh muscles to the pelvis and lower leg bones – the shinbone (tibia) and fibula. The hamstring muscles are what you use to bend and flex your knee. Strong hamstring muscles are especially important for power and balance when you sprint and jump. They are counterparts to the quadriceps muscles in the front of your thigh and are involved in almost every movement your leg makes.

A hamstring strain is commonly called a "pulled hamstring". Pulling your hamstrings too far or too fast stretches the muscle fibers, which causes a hamstring strain. A hamstring strain can range from microtears in a small area of muscle to a complete tear in the muscle or the tendons that attach the muscle to bone. In general, the term hamstring strain refers to mild or moderate damage in the muscle tissue. Completely tearing the muscles or separating them from connective tendons is usually a more serious injury, called a hamstring tear.

Sudden, explosive starts and stops and chronic overuse of the hamstring muscle-tendon unit are the most common causes of a pulled hamstring. Athletes of all abilities are equally at risk of pulling their hamstrings. More severe hamstring pulls often result from sprinting or making a quick start or stop when the leg is straight (extended). Insufficiently warming up the hamstring muscles before engaging in athletics can leave the muscles tight and at risk for pulls or strains. Chronic hamstring strains can result from overtraining that puts stress on fatigued hamstring muscles. When the quadriceps muscles are overdeveloped in relation to the hamstring muscles, you may be able to straighten your leg with an imbalanced force that damages the hamstring muscles. Inflexibility also can cause a hamstring strain. Certain athletic movements, like ballet dancing, tackling, or martial arts, may stretch your leg beyond the normal range of motion and strain tight hamstring muscles. Competitive weekend athletes who do not properly stretch and condition during the week are particularly prone to straining inflexible hamstring muscles. A direct blow to the back of your leg while the hamstring muscles are contracting, like getting hit by a squash racket or a hockey puck, can strain the hamstring muscles.

Pain in the back of your thigh can also be caused by other conditions:

   If you feel pain shooting down the back of your leg when you cough, it could be a sign of sciatica (pinching and damage in the main sciatic nerve running down your leg).

   Chills or a fever along with the hamstring pain could be symptoms of a bacterial or viral infection.

   If your leg hurts when you walk and the pain stops when you rest, it could be a sign of a circulatory problem.

If left untreated, hamstring strains are more likely to recur. This may put you at risk for developing an unstable or arthritic knee following repeated injuries. Untreated hamstring injuries may also lead to long-term inflammation in the tendon attachments to the pelvis and lower leg bones.

There usually are three parts to an orthopedic evaluation: medical history, a physical examination, and tests that your physician may order.

Your physician likely will ask about your activities, which may have caused your hamstring strain. He will probably ask when the soreness or pain began. If you have had any prior hamstring injuries, your physician will ask about the treatments you have tried in the past. Physicians usually need to know if your thigh began swelling immediately, and whether you were able to continue playing through the injury. You may also be asked about your physical and athletic goals – information that will help determine what treatment might be best for you in achieving those goals.

Physicians often can diagnose a hamstring strain by putting direct pressure on the back of your thigh. The injured area is usually tender when pressure is applied. The pain tends to increase when you bend your knee, extend your hip, or stretch the hamstring muscle. Physicians also evaluate the motion of your leg as you walk to help them diagnose the severity of your hamstring strain.

TESTS

Should your physician require a closer look, these imaging tests may be conducted:

   X-rays of the pelvis, thighbone, and knee taken from different angles can rule out fractures. If you are suffering from chronic hamstring pain, X-rays are used to check for stress fractures or vertebral disc problems in the lower back that could be causing pain in your upper leg.

   MRI (magnetic resonance imaging) is sparingly used to look for tears in the tendons or defects in the muscles that may be obscured by swelling.

RELATED TOPICS

   Imaging techniques