A hamstring injury involves straining or pulling one of the hamstring muscles — the group of three muscles that run along the back of the thigh.

Hamstring injuries often occur in people who play sports that involves sprinting with sudden stops and starts. Examples include soccer, basketball, football and tennis. Hamstring injuries can occur in runners and in dancers as well.

Self-care measures such as rest, ice and pain medicine are often all that's needed to relieve the pain and swelling of a hamstring injury. Rarely, surgery is done to repair a hamstring muscle or tendon.


A hamstring injury typically causes a sudden, sharp pain in the back of the thigh. There might also be a "popping" or tearing sensation.

Swelling and tenderness usually develop within a few hours. There might be bruising or a change in skin color along the back of the leg. Some people have muscle weakness or are not able to put weight on the injured leg.

When to see a doctor

Mild hamstring strains can be treated at home. But see a health care provider if you can't bear weight on the injured leg or if you can't walk more than four steps without a lot of pain.


The hamstring muscles are a group of three muscles that run along the back of the thigh from the hip to just below the knee. These muscles make it possible to extend the leg back and to bend the knee. Stretching or overloading any one of these muscles beyond its limit can cause injury.

Risk factors

Hamstring injury risk factors include:

  • Sports. Sports that require sprinting or running might make a hamstring injury more likely. So might other activities that can require extreme stretching, such as dancing.
  • Earlier hamstring injury. People who have had one hamstring injury are more likely to have another one. This is especially true for people who try to go back to the same activities before the muscles have time to heal.
  • Tired muscles, weak muscles and muscles that don't stretch well. Tired or weak muscles are more likely to be injured. Muscles with poor flexibility might not be able to bear the force of the action that certain activities require.
  • Muscle imbalance. Although not all experts agree, some suggest that a muscle imbalance may lead to a hamstring injury. If the quadricep muscles along the front of the thigh are stronger and more developed than the hamstring muscles, injury to the hamstring muscles might be more likely.
  • Age. Risk of injury increases with age.


Returning to tiring activities before hamstring muscles are completely healed might cause the injury to happen again.


Being in good physical condition and doing regular stretching and strengthening exercises can help lessen the risk of a hamstring injury. Try to be in shape to play your sport. Don't play your sport to get in shape.

If you have a job that's physically demanding, staying in shape can help prevent injuries. Ask your health care provider about good exercises to do regularly.