The gluteus maximus muscle is responsible for the movement of the hips and thighs. Rising from a seated position, climbing stairs and standing are all aided by this muscle.
The gluteal muscles are a group of four muscles; this group includes the gluteus maximus, the gluteus medius, the fasciae latae and the gluteus minimus muscle.
Evolution enlarged the gluteus maximus muscles in humans to strengthen the ability to stand for long periods of time. These muscles also stabilize the trunk and counteract high impact activities such as running and sprinting. Lack of activity causes these muscles to relax and weaken over time. This is often the culprit of many injuries and chronic pain. Running, hiking and single leg stance exercises all aid in strengthening the gluteus maximus.