The hamstring is a muscle group located on the back of the thigh. It consists of three muscles: the semitendinosus, semimembranosus and the biceps femoris.
Semitendinosus
The semitendinosus is a long muscle toward the inside of the back of the leg. It connects from the ischium (part of the hip) and runs down to the proximal (top) of the tibia.
Semimembranosus
The semimembranosus is the inner-most muscle of the hamstring group. Its connection points are also the ischium and the tibia.
Biceps Femoris
The biceps femoris has two heads, similar to the biceps brachii in the upper arm, with one attaching at the ischium and the other on the femur (thigh bone).
Muscle Actions
Together, the hamstring group works to flex the knee, extend the hip, and rotate the knee medially and laterally.
Strengthening Exercises
Common strengthening exercises include the leg curl and bridging.
