Hamstrings are a strong band of tissue that attach the large muscles at the back of the thigh to the bone. There are 3 main muscle group that runs along the back of the thigh, from the hip to just below the knee.

1. Semimembranosus

2. Semitendinosus

3. Biceps femoris

Hamstring muscles helps with straightening or bending of the knee and these large muscles are not very active with normal walking or standing. However, they are extremely important in power activities.