Hamstring injury

Introduction

A hamstring injury occurs when you strain or pull one of your hamstring muscles — the group of three muscles that run along the back of your thigh.

You may be more likely to get a hamstring injury if you play soccer, basketball, football, tennis, or a similar sport that involves sprinting with sudden stops and starts. Hamstring injuries can occur in runners and in dancers as well.

Self-care measures such as rest, ice, and over-the-counter pain medications are often all you need to relieve the pain and swelling associated with a hamstring injury. Rarely, surgery may be needed to repair a hamstring muscle or tendon.

Symptoms

A hamstring injury typically causes a sudden, sharp pain in the back of your thigh. You might also feel a “popping” or tearing sensation. Swelling and tenderness usually develop within a few hours. You may also experience bruising or discoloration along the back of your leg, as well as muscle weakness or an inability to put weight on your injured leg.

When to see a doctor

Mild hamstring strains can be treated at home. But you should see a doctor if you can’t bear any weight on your injured leg or if you can’t walk more than four steps without significant pain.

Causes

The hamstring muscles are a group of three muscles that run along the back of your thigh from your hip to just below your knee. These muscles make it possible to extend your leg straight behind your body and to bend your knee. When any one of these muscles stretches beyond its limit during physical activity, injury can result.

Risk factors

Hamstring injury risk factors include:

• Sports participation. Sports that require sprinting or running, or other activities such as dancing that might require extreme stretching, make a hamstring injury more likely.
• Prior hamstring injury. After you’ve had one hamstring injury, you’re more likely to have another one, especially if you try to resume all your activities at pre-injury levels of intensity before your muscles have time to heal and rebuild strength.
• Poor flexibility. If you have poor flexibility, your muscles may not be able to bear the full force of the action required during certain activities.
• Muscle imbalance. Although not all experts agree, some suggest that a muscle imbalance may lead to a hamstring injury. When the muscles along the front of your thigh — the quadriceps — become stronger and more developed than your hamstring muscles, you may be more likely to injure your hamstring muscles.