
A hamstring injury occurs when one or more of the three muscles in the hamstring muscle group—the biceps femoris, semitendinosus, or semimembranosus—are stretched beyond their limits or torn. These muscles run along the back of the thigh, connecting the pelvis to the lower leg.
Hamstring muscle injuries can range from mild strains to complete muscle tears. A hamstring strain is a common type of injury that results from overstretching, while more severe hamstring injuries can involve significant muscle fiber damage or even a rupture of the hamstring tendon.