Which muscle flexes the knee and extends the hip?

The biceps femoris is a key muscle of the hamstrings that performs the dual functions of knee flexion and hip extension. Originating from the ischial tuberosity and the femur, this muscle plays a significant role in movements such as running and jumping, where bending the knee while extending the hip is necessary.

Focusing on the functions of the biceps femoris, it works to bend the knee by pulling the lower leg upward while simultaneously assisting in extending the hip backward. This movement is important during various physical activities that require both extension of the hip and flexion of the knee, such as cycling and stair climbing.

In contrast, while other options might contribute to similar movements, they either focus primarily on one action or do not fulfil both functions simultaneously. Understanding the specific actions of these muscles highlights the biceps femoris as a crucial player in flexing the knee and extending the hip.