What muscle is the extension of the leg at the hip?

The muscle primarily responsible for the extension of the leg at the hip is the gluteus maximus. This large muscle is located in the buttocks and plays a crucial role in movements such as standing up from a seated position, climbing stairs, and running. Additionally, the hamstring muscles, which include the biceps femoris, semitendinosus, and semimembranosus, also assist in hip extension, particularly when the knee is flexed.