Hamstring injuries are common among athletes—even highly trained ones like Olympic sprinter Usain Bolt, who sustained one in 2017 during the final race of his career at the World Championships. But these injuries (also called strains) can affect recreational exercisers too, from weekend warriors to seasoned runners.
The hamstrings are composed of three muscles that run down the back of each thigh, originating at the bottom of the pelvis (ischium, or “sit-bone”) and ending just below the knee at the tibia and fibula. They are connected to these bones by tendons. Your hamstrings allow you to bend (flex) your knees and straighten (extend) your hips (as when you stretch your legs back behind you).
Hamstrings are most likely to be injured (pulled or torn) during certain types of activities, including high-speed running (sprinting) and activities that involve high kicking (martial arts, some types of dancing), lunging (fencing), and start-and-stop motion (ice hockey). Some sports, such as tennis, basketball, and soccer, incorporate a combination of these activities. The injury may be acute (occurring while you’re running at full speed, say) or chronic (arising from repeated stress or overuse).
Symptoms of an acute injury include a sudden, stabbing pain in the back of your thigh, possibly accompanied by a popping feel or sound. You may not be able to put any weight on the affected leg and might even fall to the ground. Swelling, weakness, and bruising or discoloration on the back of your leg may develop hours to days after the injury.
Mild hamstring injuries can heal uneventfully, allowing you to return to your usual activities within a week to a month, but more serious tears can take several months to mend. All hamstring injuries can have a high recurrence rate without the proper treatment, which includes rehabilitation.
Risk factors
You can’t change the first two risk factors listed below, but addressing those that can be modified may help reduce the chance of hamstring injury.
- Older age.
- A history of hamstring injury.
- Weak hamstrings.
- Taking part in high-impact sports or activities like those noted above.
- Muscle imbalance, which occurs when one muscle group (the quadriceps, for instance) is much stronger than its opposing muscle group (the hamstrings).
- A fatigued hamstring (for example, near the end of a long or hard workout).
- Poor posture during exercise.
- Tight hamstrings or tightness in other leg muscles.
- A sudden large increase in your running mileage or overall exercise program.
Getting back on (the) track
Hamstring strains are generally grouped into three categories: pulls (grade 1, or mild, the least serious), partial tears (grade 2, or moderate), and complete tears (grade 3, or severe, in which either the muscle itself ruptures or the hamstring tendon disconnects from the bone, called an avulsion).
Most mild strains can be treated with simple, nonsurgical therapies. If you are not limping with slowed walking and your pain is minimal, start with self-care measures, using the acronym RICE: rest, ice, compression (using an elastic bandage; start closer to the knee and wrap upward, and keep it on except when bathing), and elevation (ideally above the heart). Some sources advise a variation, PRICE, in which the “P” stands for protection—for example, with a brace or crutches, to help prevent further injury. If needed, over-the-counter pain relievers such as ibuprofen (Advil, Motrin, or generics) and acetaminophen (Tylenol or generics) can help relieve discomfort.
Once pain and swelling have subsided, you can begin gentle stretching to restore flexibility. Gradually add exercises to strengthen the hamstring muscles. The UC San Francisco Sports Medicine Center offers a list of illustrated exercises for hamstring rehabilitation, along with videos.
For moderate to severe injuries—or if pain and swelling don’t improve after two to three days of self-care—see your health care provider. You might be referred to a physician specializing in musculoskeletal injuries, such as a sports medicine physician or orthopedic surgeon, who may perform ultrasound imaging or order an MRI.
You might also be referred to a physical therapist for rehabilitation, including exercises to help your muscle function return to normal and reduce the formation of scar tissue (which increases the risk of reinjury). One type that is often incorporated is eccentric exercise, which is movement that lengthens a muscle at the same time it’s contracting. Physical therapists also offer modalities such as therapeutic ultrasound, low-level laser therapy, or hands-on soft tissue work—but there isn’t conclusive evidence that these are beneficial.
Hamstring avulsions will most likely require surgery to reattach the tendon, typically followed by 6 to 12 months of rehab before returning to sports activities.
