The Hamstring is a collective three muscles situated between the ischial tuberosity (lower portion of the pelvic 'goggles')and the tibia and fibula (lower leg bones just below the knee).

This collective cross two joints, the hip and knee. These attachments mean the main movements they provide are bending of the knee, and extension of the hip (pulling of the thigh backwards).

The Hamstrings play a crucial role in many daily activities, such as, walking, running, jumping, and controlling some movement in the trunk. In walking, they are most important as an antagonist to the quadriceps in the deceleration of knee extension.

The Hamstrings plays an essential role in characterizing body flexibility, making it an important muscle to maintain via stretching and exercising.