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A hamstring strain occurs when one of the muscles in the hamstring group in the back of the leg gets torn. These three muscles are involved in a number of movements of the hip and knee, and they are most classically torn as a result of vigorous athletic activity such as running, jumping, or stretching too deeply. The biceps femoris, semitendinosus, or semimenbranosus muscle may be involved in a hamstring strain.
Hamstring strains are graded by intensity, from Grade I, a microscopic tear which causes some bleeding and pain, to Grade III, a severe tear which can sometimes require surgical repair. The first sign of a hamstring strain is often a sharp pain in the back of the leg, which may onset during exercise. Other signs can include bruising, heat, swelling, and stiffness. With severe tears, people may find it very difficult to walk, and the muscle can also be very painful.
Treatment for a hamstring strain requires resting to give the muscle an opportunity to heal. Cold therapy can help reduce pain and swelling, and people should try to avoid putting stress on the healing muscle. Gentle stretching during the healing phase can, however, keep the muscles in the leg strong. A physical therapist can provide assistance with stretches and other forms of gentle exercise, for athletes who want to keep fit while recovering.
A common problem with a hamstring strain is that people tend to return to normal activity levels before the muscle is fully healed, resulting in a recurrence of the strain. The tearing can also grow worse as a result of stressing the muscle before it is ready. It is important to be evaluated by a doctor before returning to previous levels of activity with a hamstring strain, to confirm that it is safe to start pushing the muscle again. It is also advisable to take things slowly, rather than plunging into high intensity exercise.
There are some steps which can be taken to prevent this common sports injury. Stretching fully and warming up before exercise will loosen the muscles and get them ready for hard work, reducing the risk of a strain. Cooling down after exercise will also keep the muscles in good condition. It can also help to work with a massage therapist or physical therapist during training to identify early signs of strain and fatigue so that they can be addressed before they progress into full-blown injuries.