The largest muscle in the human body is the gluteus maximus, which is located in the buttocks. The gluteus maximus is a broad and powerful muscle that helps to extend the hip and thigh, and also assists in lateral rotation of the thigh. It is responsible for many of the movements that we perform on a daily basis, such as walking, running, and climbing stairs. The gluteus maximus is also important for maintaining good posture and stability of the pelvis and spine. In some athletes, such as runners and sprinters, the gluteus maximus can become particularly well-developed due to the demands of their sport.