What YOU need to know about Hamstring Injuries
A hamstring muscle pull or strain is an injury to one or more of the muscles at the back of the thigh. Sometimes called a pulled hamstring, it occurs frequently in athletes, especially those who participate in sports that require sprinting, like track, soccer, and basketball.
The hamstring muscle group is comprised of three muscles which run down the back of the thigh, and help extend the leg straight back and bend the knee. The muscles start at the bottom of the pelvis, cross the knee joint, and end at the lower leg. Hamstring muscle fibers join with the tough, connective tissue of the hamstring tendons near the points where the tendons attach to bones.
A hamstring injury can be a pull, a partial tear, or a complete tear. Muscle strains are graded according to their severity, from grade 1 which is mild and usually heals readily, to grade 3 which is a complete tear of the muscle that may take months to heal.
Most hamstring injuries occur in the thick part of the muscle or where the muscle fibers join tendon fibers. In the most severe hamstring injuries, the tendon tears completely away from the bone, and may even pull a piece of bone away with it. This is called an avulsion injury.
Muscle overload, the main cause of hamstring muscle strain, can occur when the muscle is stretched beyond its capacity or challenged with a sudden load. Strains often occur when the muscle lengthens as it contracts. Called an eccentric contraction, this happens when you extend a muscle while it’s weighted, or loaded.
During sprinting, the hamstring muscles contract eccentrically as the back leg is straightened and the toes are used to push off and move forward. At this point in the stride, the hamstring is not only lengthened, but also loaded with body weight, as well as the force required for forward motion. Like strains, hamstring tendon avulsions are also caused by large, sudden loads.
Several factors make a muscle strain more likely, including muscle tightness, muscle imbalance (when one muscle group is much stronger than its opposing muscle group), poor conditioning, and muscle fatigue.
Hamstring strains occur more often in adolescents than in other age groups because bones and muscles don’t grow at the same rate. During a growth spurt, a child’s bones may grow faster than muscles, pulling the muscle tight. A sudden jump, stretch, or impact can tear the muscle away from its connection to the bone.
If you strain your hamstring while sprinting in full stride, you’ll notice a sudden, sharp pain in the back of your thigh, causing you to come to a quick stop.
Additional symptoms may include swelling during the first few hours after injury, bruising or discoloration of the back of the leg below the knee over the first few days, or weakness in the hamstring that can persist for weeks.
Diagnosis & Treatment
Your doctor or orthopedic surgeon will ask about the injury, check your thigh for tenderness or bruising, and palpate the back of your thigh to see if there is pain, weakness, swelling, or a more severe muscle injury.
Imaging tests, including x-ray and MRI may help your doctor confirm your diagnosis. X-ray will show whether you have a hamstring tendon avulsion, while MRI can help better determine the degree of the injury.
Treatment of hamstring strains varies depending on the type of injury and its severity.
Most hamstring strains heal well with simple, nonsurgical treatment. The RICE protocol (Rest, Ice, Compression, Elevation) is effective for most sportsrelated injuries. Your doctor may also recommend you wear a knee splint for a brief time, to keep your leg in a neutral position to help it heal. Early treatment with a plan that includes the RICE protocol and physical therapy has been shown to result in better function and quicker return to sports.
Once the initial pain and swelling has settled down, physical therapy can begin. Specific exercises can restore range of motion and strength, focusing first on flexibility and gentle stretching, and progressing to strengthening exercises.
Surgery is most often performed for tendon avulsion injuries, where the tendon has pulled completely away from the bone. Surgery may also be needed to repair a complete tear within the muscle.
To repair a tendon avulsion, your orthopedic surgeon will pull the hamstring muscle back into place and remove any scar tissue. Then the tendon is reattached to the bone using large stitches or staples. A complete tear within the muscle is sewn back together using stitches.
Post-surgery, you’ll need to keep weight off of the leg to protect the repair. In addition to crutches, you may need a brace to keep your hamstring in a relaxed position. How long you’ll need these aids will depend on the type of injury you have, typically three to six months. Your doctor will tell you when it’s safe to return to sports.
To prevent re-injuring your hamstring, be sure to follow your doctor’s treatment plan. Return to sports only after your doctor has given you the goahead. Reinjuring your hamstring increases your risk of permanent damage, which can result in a chronic condition.
Flexibility is important for the prevention of hamstring injuries. Maximize flexibility with a regular stretching program as well as a period of warm-up and stretching before athletic activity.