The muscles in the posterior compartment of the thigh are collectively known as the hamstrings. They consist of the biceps femoris, semitendinosus and semimembranosus, which form prominent tendons medially and laterally at the back of the knee.
As group, these muscles act to extend at the hip, and flex at the knee. They are innervated by the sciatic nerve (L4-S3).
Most injured muscle
A hamstring strain refers to excessive stretch or tearing of the muscle fibres. They are often seen athletes involved in running or kicking sports. Damage to the muscle fibres is likely to rupture the surrounding blood vessels – producing a haematoma (a collection of blood). The haematoma is contained by the overlying fascia lata.
Among runners, the most commonly injured muscle is the hamstring, according to a 2012 review study. That research found that hamstring injuries affect about 7 percent of runners.
Roller-massager application to the hamstrings increases sit-and-reach range of motion within five to ten seconds without performance impairments.