The muscles in the back of the thigh (hamstrings) can be strained (hamstring pull) in any running activity.

The hamstrings move the hip and knee backward. A hamstring injury often occurs when the hamstrings are contracted suddenly and violently, as can occur when a person sprints. It causes sudden pain in the back of the thigh. Hamstring injury can also develop more slowly, usually caused by inadequate flexibility training.

Doctors make the diagnosis based on the person's symptoms and results of a physical examination. Sometimes magnetic resonance imaging (MRI) is also needed.

Treatment

Ice and use of a thigh sleeve for compression and support are needed immediately after injury. Nonsteroidal anti-inflammatory drugs (NSAIDs) or other analgesics are used to relieve pain. If walking is painful, the person may need crutches initially.

Once pain begins to resolve, the hamstrings should be gently stretched. When the pain has completely resolved, the quadriceps and hamstrings are gradually strengthened. The person should not run or jump until satisfactory muscle strength and range of motion have been regained. Recovery may occur in days or weeks, but a severe hamstring injury can often take up to several months to completely heal.

Strengthening the Hamstrings
Attach a 5-pound (2-kilogram) weight to the foot on the injured side and lie face down on a bed with the lower part of the body (from the waist down) off the bed and the toes touching the floor. Keeping the knee straight, slowly raise and lower the leg. Do 3 sets of 10 every other day. As strength returns, use increasingly heavier weights. This exercise strengthens primarily the upper part of the hamstrings. Attach a 5-pound (2-kilogram) weight to the foot on the injured side. Stand on the other leg. Slowly raise the weighted foot toward the buttocks by bending the knee, and lower it toward the floor by straightening the knee. Do 3 sets of 10 every other day. As strength returns, use increasingly heavier weights. This exercise strengthens primarily the lower part of the hamstrings.

Last full review/revision February 2009 by Paul L. Liebert, MD