A hamstring injury is an injury to the group of three muscles that run along the back of the thigh and occurs due to a strain or pull of one of the hamstring muscles.

A hamstring injury is likely to occur during sports that involve sprinting or sudden stops and starts such as football and tennis but it can also occur in dancers and runners.

A hamstring injury can be treated with self-care measures such as rest, ice and over-the-counter pain relievers to reduce the pain and swelling. In rare cases, surgery may be necessary to repair a torn muscle.



The typical symptoms of a hamstring injury include sudden, sharp pain in the back of the thigh sometimes accompanied by a popping or tearing sensation. Swelling and tenderness in the affected area occurs within a few hours of the injury. Other symptoms may include bruising or discoloration on the back of the thigh as well as muscle weakness or inability to put weight on the injured leg.

Persistent or significant pain when attempting to walk or inability to bear any weight on the injured leg may indicate that medical attention is necessary.



The hamstring muscles (group of three muscles) run along the back of the thigh from the hip to just below the knee. These muscles enable the leg to extend straight behind the body and to bend the knee. Stretching of any of the muscles beyond its limit during physical activity can lead to an injury.


Risk factors

Factors that increase the risk of a hamstring injury include:


  • Sports: sports that require extreme stretching, running or sprinting
  • Prior hamstring injury: a prior hamstring injury makes one more susceptible to another one, especially if the activities prior to the injury are continued with the same intensity
  • Poor flexibility: muscles may not be able to bear the full force of an action required during certain activities
  • Muscle imbalance: if the muscles along the front of the thigh (quadriceps) become more developed and stronger than the hamstring muscles, it is more likely to injure the hamstring muscles



Performing the same intensive activities before the hamstring muscles are completely healed may lead to an injury recurrence. In some cases, a recurrent hamstring injury may be more severe than the first injury.



Regular stretching and exercises help strengthen the hamstring muscles and minimize the risk of an injury.