The hamstring is composed by three muscles located on the back of the thigh called: Semistendinosus, Biceps femoris ad Semibranosus. They attach from the back of the pelvis at the ischial tuberosity to just below the knee joint on the medial and lateral sides. Their function is to facilitate the extension of the leg or straightening the leg backwards and also allows the knee to bend.
A strain or a "pulled muscle" is when there is a stretch, partial tear or a complete tear in the muscle. The most common causes for this strain are stretching the muscle more than its capacity or when they are contracted with a great force. It is seen mostly with sprinting, dancing, running or jumping. This strain is very common in adolescents since they are in the stage of growing, the bone usually grows faster than the muscle and it could pull the tendon. The symptoms with this injury are: swelling, pain and burning sensation when it occurs, bruising or discoloration on the back of the leg over the course of the first days and weakness in the hamstring for weeks.
The diagnosis would be determined with the history of the patient and the physical examination. The physican would inspect the back of the thigh for any tenderness, weakness or bruising. X-rays can be used to determine if the tendo of the hamstring has pulled completely from the bone and if part of that bone pulled away. If this happens this is called avulsion injury. MRI can also be used to determine the grade of the strain.
The treatment for this injury depends on the degree of the injury. If it is a minor sprain, it could be treated with NSAIDS (Ex. Ibuprofen and Naproxen), resting from physical activities, icing it for 20 minutes several times a day, elevation to reduce swelling, knee splints, and physical therapy. If there is a tendon avulsion injury, surgical procedure would be done to attach the tendon to the pelvis with stitches. This typically takes at least 6 months to heal properly with the instructions of the physician.
There are several ways to prevent this type of injury from happening like stretching or warming up before doing exercise, sprinting or running. Also, the muscles must have a good strength so it is important to do as many exercises as you can in the day. These exercises can help in the quality of life and also prevents any possible injuries in the future.
