What is the primary action of the biceps femoris muscle?

The primary action of the biceps femoris muscle is to extend the hip and flex the knee. This muscle is one of the main components of the hamstrings group located at the back of the thigh. During activities such as running or jumping, the biceps femoris plays a crucial role in bending (flexing) the knee while also aiding in the extension of the hip joint. This dual function is essential for coordinated movement, as it allows for powerful leg movements necessary for various physical activities.

Understanding this action is important for those studying human anatomy and physiology, especially in relation to movements involving the lower limb and its contribution to locomotion and athletic performance.