hamstrings

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Hamstrings are the muscles of the back of the thigh: ‘ham’ being appropriate to describe the bulk of the muscles, and ‘strings’ to describe their tendons behind the knee. These muscles span both the hip joint and the knee joint, because they are attached above to the pelvic bone, and below to the tibia. By virtue of these attachments they are the muscles that bend the knee, and they can also assist extension at the hip (backward movement of the leg). Stretching routines to encourage flexibility of the hamstring muscles therefore involve bending at the hip whilst straightening the knee. The semitendinosus (its lower half mostly tendon, hence the name) and the semimembranosus (its upper part a flattened tendon) form the hamstring tendons on the inner side; the biceps femoris forms the hamstring tendon on the outer side. These can be felt easily when the knee is bent.

— Stuart Judge

See musculo-skeletal system.

The term ‘hamstrings’ properly refers to the prominent tendinous cords at the back of the knee which attach the rear thigh muscles to the lower leg, but it is more commonly applied to the muscles themselves. In the latter sense, the hamstrings consist of a group of three large muscles (biceps femoris, semitendinosus, and semimembranosus). They extend and rotate the hip, and flex the knee. They are very susceptible to pulls and strains, especially when a runner tries to sprint without a sufficient warm up. Such pulls can be very dramatic, being accompanied by a loud ‘pop’ if the muscle is actually ruptured. Hamstring strains should be treated initially with ice and compression (see RICE).