Your Orthopaedic Connection: Hamstring Muscle Strain

Hamstring Muscle Strain

Anyone who watches sports knows that a "pulled hamstring" is a troublesome and sometimes painful condition for athletes. The hamstrings are the muscles at the back of your thigh. These muscles help to straighten (extend) the leg at the hip and bend (flex) the leg at the knee. A "pulled" hamstring is a strain or tear in the muscles or tendons.

Anyone can experience hamstring strain, but most people at risk for this injury are:

Adolescent athletes who are still growing
Professional athletes (football, soccer, skating, or running)
Runners or sprinters
Dancers
Older athletes whose exercise program is primarily walking

Causes

Hamstring injuries are easier to prevent than cure. But to understand what causes a hamstring injury, you first have to know how muscles work.

How Muscles Work

All muscles work in pairs to perform a task. One set of muscles shortens (contracts) to exert force, while the other set of muscles relaxes. The hamstring muscles, located at the back of the thigh, work with the quadriceps muscles in the front of the thigh. When you bend your leg, the hamstring muscles contract and the quadriceps muscles relax. Conversely, when you straighten your leg, the quadriceps muscles contract and the hamstring muscles relax.

Strains and Tears

When one muscle group is much stronger than its opposing muscle group, the imbalance can lead to a strain. This frequently happens with the hamstring muscles. The quadriceps muscles are usually much more powerful, so the hamstring may become fatigued faster than the quadriceps. A fatigued muscle cannot relax as easily when its opposing muscle contracts, leading to strains.

Muscle strains are overuse injuries that result when the muscle is stretched without being properly warmed up. It's like pulling a rubber band too long. Eventually, the rubber band will either lose its shape or tear apart. The same thing happens with muscles.

Hamstring strain in young people often occurs because bones and muscles do not grow at the same rate. During a growth spurt, the bones may grow faster than the muscles. The growing bone pulls the muscle tight, and a sudden jump, stretch, or impact can tear the muscle away from its connection to the bone.

Sometimes, a muscle that tears away from a bone will pull a piece of bone with it. This is called an avulsion injury. If the hamstring tears near the hip, where it attaches to the pelvis, it may pull a piece of hip bone (ischium) away. This is a serious injury that may require surgery to reattach the muscle.

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Diagnosis

Hamstring injuries are usually readily apparent.

Mild strains may involve a simple tightening of the muscle that you can feel.
More severe injuries may result in a sharp pain in the back of the thigh, usually in full stride.
A rupture or tear may leave you unable to stand or walk. The muscle may be tender to the touch, and it may be painful to stretch your leg. Within a few days after a tear, bruising may appear.

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Treatment

Remember RICE (Rest, Ice, Compression, Elevation), and you will know the immediate treatment protocol for many sports-related injuries, including hamstring pulls or strains.

A brief period in a knee splint may be prescribed.

If the muscle is completely torn, surgery may be necessary to repair and reattach it. No treatment is complete without proper rehabilitation to strengthen and stretch the muscle.

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Prevention

The best way to prevent a hamstring injury is to stretch before and after an activity. Weak or tight hamstrings can contribute to low back pain, so doing exercises to strengthen and stretch the hamstrings may also reduce your risk of low back pain.

Sit down and straighten your left leg. The sole of your right foot should rest next to the inside of your straightened leg. Lean slightly forward and touch your foot with your fingers. Keep your left foot upright with the ankle and toes relaxed. Hold for 30 seconds. Repeat with right leg.

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Last reviewed and updated: August 2007

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