Hamstring Strain

Medically reviewed & edited by Dr. Max Trotz,
MBBS (State Examination), MRCP (Edin), DCH

A hamstring strain is a muscle injury resulting from tearing or other damage to the muscles and associated fibres at the back of the upper leg. There are different grades of injury ranging from a grade 1 or mild hamstring strain (sensation of cramp or tightness) to grade 3 (tearing of the muscle). Another name for this injury is a “pulled hamstring”.

These strains are commonly experienced by athletes across a broad range of injuries, but are especially prevalent in track and field athletes like sprinters. They usually occur as traumatic as opposed to overuse injuries. Predisposing factors include muscle weakness or imbalance, poor flexibility, fatigue and poor running technique. Additionally, those who have previously experienced such an injury are particularly liable to experience one again.

Causes & Risk Factors

The hamstring “muscle” is actually a group of three muscles running down the back of the thigh. This muscle group is responsible for bending the leg at the knee as well as extending the thigh.

A hamstring strain is the result of one or more of these muscles becoming overloaded. If the strain is at the severe end of the spectrum, the muscles may even be torn.

The following factors can increase the risk of a hamstring strain:

• Failing to warm up properly before commencing a bout of physically strenuous activity as well as unsatisfactory training procedures, especially if the activity involves running or jumping;
• Tightness in the quadricep muscles at the front of the thigh as they pull the pelvis forward, resulting in additional tightness of the hamstrings. This can be due to a strength imbalance caused by a discrepancy between the strength of the quadriceps and that of the hamstrings;
• The hamstring muscles work in tandem with those of the gluteus (or “glutes”). If the glutes are too weak, this can result in an additional load on the hamstring muscles. The risk of a hamstring strain can then be higher as a result;
• Having experienced an earlier hamstring injury can predispose an individual to another such injury.

Symptoms Of A Hamstring Strain

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The symptoms of a hamstring strain can be anything  from mild to being so severe (for a grade 3 injury) that walking or standing may be impossible. In general, victims of this injury will experience the following:

• At the time the injury occurs, sudden and severe pain along the back of the thigh;
• The individual may also hear or sense a snapping or popping sound at the time of occurrence of the injury;
• After the onset of the injury, the individual may experience continuing pain and swelling along the back of the thigh, especially when walking. Activities involving  bending over or straightening the leg (when the hamstring muscle is extended) will also result in pain;
• Reduced range of motion of the knee joint;
• Tenderness along the back of the leg;
• Possible contusion or bruising in the same area.

If you experience one or more of the symptoms listed above, you should seek a consultation with a doctor (ideally one with a sports medicine background).

A hamstring injury can be classified, depending on severity, into 1st, 2nd or 3rd degree injuries (or grade 1, 2 or 3).

In a grade 1 injury, there is no significant tissue disruption and no loss of function or strength.

A grade 2 injury is one in which tissue damage causes a reduction in strength with preservation of some residual function.

A grade 3 injury is present when there is complete disruption of the musculotendinous unit with complete loss of its function.

Examination & Diagnosis

To make a diagnosis, the doctor will likely perform a physical examination of the leg. He or she may also ask questions about the nature and severity of the pain being experienced.

The doctor may also ask questions about the cause of the injury e.g. what was the patient doing when it occurred? Armed with this information, the doctor should then be able to make a formal diagnosis.

Treatment Of A Hamstring Strain

Conservative Treatment

If the hamstring strain lies in the mild or moderate categories, treatment will generally follow the conservative P.R.I.C.E. protocol. This is usually adequate to heal most strains that are not in the most severe category.

The P.R.I.C.E. protocol will involve:

• Protect the leg from further injury
• Resting the leg and hamstring muscles for a while (48-72 hours). In practice, this will mean avoiding putting any weight on the leg.The patient should consider using crutches if he or she needs to move around. The doctor or therapist will be able to advise if this may be necessary;
• Applying Ice to the hamstring area, or alternatively a cold compress. This should be done for periods of 20 minutes or so and at intervals of 2-3 hours. Ice will help to reduce the blood flow to the injured area and also the pain and swelling of the injury;
• If the pain and swelling are severe, the doctor may prescribe a non-steroidal anti inflammatory drug (NSAIDS) such as Ibuprofen or naproxen. However, the patient should take care to ask about possible side effects from the use of these drugs;
• Applying Compression to the hamstring muscles by wearing a thigh compression sleeve, compression shorts or a tensor bandage. This will increase blood circulation through the affected area;
• Trying to keep your leg Elevated as much as possible when lying or sitting down. For example, placing the leg on a pillow when lying down will help the blood drain from the injured area. It will then be replaced by fresh blood with nutrients that accelerate healing of the injured muscles.

Apart from non-steroidal anti-inflammatory drugs like ibuprofen and naproxen, medications like paracetamol and topical anti-inflammatory preparations can also be used.

Surgical Treatment

For a grade 3 hamstring strain that involves tearing of the muscles, a conservative approach as outlined above may not be sufficient. Surgery is usually needed when there is complete avulsion (severing) of the proximal hamstrings. The doctor may instead suggest surgery to repair the damaged muscles and reattach them.

Physical Therapy

Once healing of the hamstring strain is underway, the patient may be referred to a physical therapist who can devise an exercise program to stretch and strengthen the hamstring muscles. Following this rehabilitation program will help to reduce the risk of experiencing another hamstring strain.

How Long Will It Take To Recover?

This will depend on the severity of the injury and on the patient. The average hamstring injury will usually heal over a 2-3 week period. However, grade 3 injuries can take up to several months to heal. In order to keep the recovery time to a minimum, we suggest the following:

• Avoid applying heat to the affected area until the injury has completely healed
• Avoid use of alcohol during the recovery period;
• Do not massage the hamstring muscles during this period;
• Do not return to sport or regular activities until you have the same strength and range of motion in the injured leg as with the other one.
• Avoid running or any other form of exercise (like jogging, sprinting and jumping) which may cause further damage

Prevention Of Hamstring Injuries

As with all other injuries, an ounce of prevention is worth a pound of cure. Hence, it is reasonable to ask how hamstring strains can be prevented in the first place. Although the risk of this unpleasant injury may be difficult to eliminate completely, athletes or physically active individuals can reduce it as follows:

• Making sure they warm and and stretch properly before any exercise or other physically strenuous activity;
• Avoid sudden increases in training intensity;
• Listen to your body – stop as soon as you feel any pain or discomfort in the hamstring area;
• Individuals can also enroll in a physical therapy program that comprises stretching and strengthening exercises for the hamstring muscles. This is different than following this type of program as a rehabilitative measure as described above.;
• Performing Nordic hamstring exercises.