Pulled Hamstring

Information About Hamstring Muscle Strains

hamstring pain
Hamstring injuries cause pain in the back of the thigh.. Jeannot Olivet / Getty Images

The hamstring muscles are a group of large, powerful muscles that span the back of the thigh, from the lower pelvis to the back of the shin bone. The hamstring muscles are important in their functions to both extend the hip joint and bend the knee joint.

These hamstring muscles are used in many sporting activities, as well as in normal daily activities. Sports that commonly cause a hamstring injury including sprinting sports that involve sudden accelerations.

These include track and field, soccer, and basketball.

A hamstring injury can also occur as a result of a direct blow to the muscle, such as being kicked in the back of the thigh, or falling on the back of the thigh. Hamstring contusions are different from pulled hamstrings, although they may cause similar symptoms.

Pulled Hamstring

A pulled hamstring, also called a hamstring strain, is a tear of the hamstring muscle fibers. Hamstring tears are usually graded similar to other types of muscle strains:

  • Grade I Hamstring Strain: Mild discomfort, often no disability. Tearing of the muscle fibers is microscopic, essentially stretching the muscle too far. Usually minimal limitations in activity.
  • Grade II Hamstring Strain: Moderate discomfort, can limit an athlete's ability to perform activities such as running and jumping. May have moderate swelling and bruising.
  • Grade III Hamstring Strain: Severe injury that can cause pain with walking. Muscle fibers significantly or completely torn, potentially requiring surgical intervention. Often patients complain of muscle spasm, swelling, and significant bruising.

    Muscle strains and tears most commonly occur because of what is called an eccentric contraction. When an eccentric contraction of the muscle occurs, the muscle is trying to contract while another force (the ground, another player, etc.) is forcing the muscle in the opposite direction. This creates tremendous strain on the muscle, and if the force is strong enough, it will tear the muscle fibers.

    Hamstring muscle injuries are also common because the muscle spans more than one joint. The origin of the hamstring is on the lower part of the pelvis, and the insertion is on the upper part of the shin bone. Therefore, the muscle crosses both the hip and the knee. Movements of both of these joints can increase the forces acting on the hamstring muscle. Other muscles that cross more than one joint (such as the gastrocnemius, or calf muscle) are also more prone to muscle strain injuries.

    Symptoms of a Torn Hamstring

    The symptoms of a pulled hamstring depend on the severity of the injury. The hamstring injury is usually sudden and painful. Other common symptoms include:

    • Bruising: Small tears within the muscle cause bleeding and subsequent bruising. The bruise begins in the back of the thigh, and as time passes the bruise will pass down below the knee and often into the foot.
    • Swelling: The accumulation of blood from the hamstring injury causes swelling of the thigh. This can make further muscle contraction difficult and painful. Wearing a compressive bandage can help control the swelling.
    • Muscle Spasm: Muscle spasm is a common and painful symptom of a hamstring injury. Because of the trauma to the muscle, signals of contraction are confused, and the muscle may be stimulated. If severe, muscle relaxants can help with spasms.
    • Difficulty With Muscle Contraction: Bending the knee is often painful after a pulled hamstring, and can even prevent the patient from walking normally. If you are unable to contract the hamstring, the muscle may be completely ruptured.

    Treatment of a Torn Hamstring

    Treatment of a pulled hamstring is dependent on the severity of the injury. Because of bleeding and swelling, athletes should stop their activity and rest immediately. An ice pack and compressive bandage can be applied to control swelling. Crutches may be necessary if walking is painful or if spasms are severe. If the pain is significant, or if the symptoms do not steadily resolve, medical evaluation should be obtained. Signs to see a doctor include:

    • You have difficulty walking
    • The pain is significant and not relieved with rest
    • You think you may have a complete hamstring rupture

    Unfortunately, without proper treatment, hamstring muscle injuries can cause recurrent symptoms. The good news is, that with proper treatment, these injuries can be prevented, and athletes generally return to full, pre-injury levels of sports activity.


    Noonan TJ, and Garrett WE, "Muscle strain injury: diagnosis and treatment" J. Am. Acad. Ortho. Surg., Jul 1999; 7: 262 - 269.

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