The hamstrings are the 3 muscles that make up the back of the thigh, including the semitendinosus, the semimembranosus, and the biceps femoris. These muscles allow you to bend your leg at the knee.
Yet, hamstring strains can be fairly painful. They often arise during activities that require frequent sprinting bouts followed by frequent stops or pivots. It’s not uncommon for runners, dancers, soccer players, basketball players, football players, or tennis players to experience a hamstring strain.