Hamstring injury (muscle strain)

Causes of a hamstring injury

The hamstring muscles, is the common name for the muscles, at the back of the thigh, responsible for bending the leg at the knee and moving the thigh bone backwards.

The term ‘hamstring muscles’ is used to describe the group of three muscles:

• semitendinosus
• semimembranosus
• biceps femoris

A hamstring injury can occur if any of the tendons or muscles are stretched beyond their limit.

They often occur during sudden, explosive movements, such as:

• sprinting
• lunging
• jumping

They can also occur more gradually, or during slower movements that overstretch your hamstring.

Recurring injury is common in athletes and people regularly taking part in sporting activities. This is because you’re more likely to injure your hamstring if you've injured it before.

Regularly doing stretching and strengthening exercises, and warming up before exercise, may help reduce the risk of injuring your hamstring.

Different grades of hamstring injury

There are three grades of hamstring injury. These vary in severity and the length of time they take to recover from.

Mild hamstring strains (grade 1)

• will usually cause sudden pain and tenderness the back of your thigh
• it may be painful to move your leg
• strength of the muscle shouldn't be affected

Partial hamstring tears (grade 2)

• usually more painful and tender
• may be some swelling and bruising at the back of your thigh
• you may have lost some strength in your leg

Severe hamstring tears (grade 3)

• will usually be very painful
• will usually be tender, swollen and bruised
• may have been a "popping" sensation at the time of the injury
• you'll be unable to use the affected leg

When to see your GP

Most hamstring injuries can be cared for at home using the techniques below.

If you have access to a physiotherapist, they will be best placed to advise you how to manage the injury.

See your GP if:

• you have any concerns about your injury
• you think it's a severe injury
• it's not healing
• your symptoms are getting worse

Your GP can advise you about when you can return to your normal activities. They can also suggest exercises you should do to aid your recovery. 

Your GP may refer you to a physiotherapist for specialist treatment in some cases.

Treatment for a hamstring injury

Recovering from a hamstring injury may take days, weeks or months. This will depend on how bad the strain or tear is.

A completely torn hamstring may take several months to heal. You’ll be unable to resume training or play sport during this time.

During the first two or three days, you should care for your injury using PRICE:

• protection - protect from further injury (for example by using a support or high-top, lace-up shoes)
• rest - avoid activity for the first 48 to 72 hours following injury
• ice - apply ice wrapped in a damp towel for 15 to 20 minutes every two to three hours during the day for the first 48 to 72 hours following the injury (this should not be left on whilst the person is asleep)
• compression - with a simple elastic bandage or elasticated tubular bandage, which should be snug but not tight, to help control swelling and support the injury (this should be removed before going to sleep)
• elevation - keep the injured area elevated and supported on a pillow until the swelling is controlled (if the leg is injured, long periods of time with the leg not elevated should be avoided)

Avoid HARM (Heat, Alcohol, Running, and Massage) in the first 72 hours after the injury

Regular painkillers, such as paracetamol or a non-steroidal anti-inflammatory drug (NSAID) cream or gel, may also help relieve the pain.

An oral NSAID (for example ibuprofen) can be taken 48 hours after the initial injury, if needed.

Ask your GP or pharmacist if you need advice about pain relief.

Gentle exercises and stretches

Returning to strenuous exercise too quickly could make your injury worse.

But avoiding exercise for too long can cause your hamstring muscles to shrink and scar tissue to form around the tear.

To avoid this, you should start doing gentle hamstring stretches after a few days. This is when the pain has started to subside.

This should be followed by a programme of gentle exercise, such as: 

• walking
• cycling
• hamstring strengthening exercises

Your GP can give you further advice and, if necessary, refer you to a physiotherapist for a suitable exercise programme.

To avoid injuring yourself again, you should only return to a full level of activity when your hamstring muscles are strong enough. Your physiotherapist or GP will be able to advise you about this.

Many people need to avoid sports for at least a few weeks. But the length of time you need off will depend on the severity of your injury.

More useful links

• How to use your health services