A hamstring strain is a partial tear of the hamstring muscles most commonly at the musculotendinous junction.

Hamstring strains are common among runners. Athletes at risk include those with poor flexibility of the hamstring muscles, inadequate pre-participation stretching and warm up, and previous injury. Older athletes are also at higher risk. As with any muscle strain, the amount of force that caused the muscle to tear determines the degree of injury.

Symptoms and Signs

Strains of the hamstring muscles can manifest as an acute painful area in the posterior thigh when sprinting or running or develop more slowly, usually because of inadequate flexibility training.

Diagnosis

• Clinical evaluation

The diagnosis is confirmed by finding hamstring pain with knee flexion against resistance as well as on palpation of the posterior thigh. In mild strains, tenderness and mild swelling are present. In more severe strains, ecchymosis, moderate to severe swelling, and poor muscle function caused by pain and weakness are present.

Treatment

• Rest, ice, and compression
• Stretching, then strengthening exercises

Ice and compression with use of a thigh sleeve should begin as soon as possible. NSAIDs and analgesics are prescribed as necessary, and crutches may be required initially if walking is painful.

Once pain begins to resolve, patients should begin gentle hamstring stretching. When the pain has completely resolved, gradual strengthening of the quadriceps and hamstrings is begun (see Sidebar 5: Sports Injury: Strengthening the Hamstrings).

Only when satisfactory strength has been achieved should patients resume running. Athletes must be made aware that recovery from hamstring injury can often take up to several months, depending on the severity.

Sidebar 5
Strengthening the Hamstrings
Upper part of the hamstrings Attach a 2-kg (5–lb) weight to the foot on the injured side. Lie face down on a bed with the lower part of the body (from the waist down) off the bed and the toes touching the floor. Keeping the knee straight, slowly raise and lower the leg. Do 3 sets of 10 repetitions with 1 min of rest between repetitions. As strength returns, use increasingly heavier weights. Do this exercise every other day. Lower part of the hamstrings Attach a 2-kg (5-lb) weight to the foot on the injured side. Stand on the other leg. Without bending the hip, slowly raise the weighted foot toward the buttocks by bending the knee, and lower it toward the floor by straightening the knee. Do 3 sets of 10 repetitions with 1 min of rest between repetitions. As strength returns, use increasingly heavier weights. Do this exercise every other day.

Last full review/revision April 2009 by Brian D. Johnston; Paul L. Liebert, MD