Gluteus medius: This muscle is located somewhat higher up the body than the gluteus maximus, rather than on top of the gluteus maximus. To put it another way, growing the gluteus maximus will increase the size of your buttocks from front to back, but building the gluteus medius would increase the size of your buttocks from side to side. Most people have a larger gluteus medius than maximus because most people use their muscles in ways that stress the gluteus medius more than the maximus. The gluteus medius is one of the three main muscles of the hip. It acts to extend the leg and rotate it outward. Without this muscle, walking would be impossible since it provides the force that raises the foot off the ground at the end of each step. The gluteus medius is also important in maintaining posture because its contraction helps to lift the head and shoulders high when you stand up straight. Finally, the gluteus medius plays an important role in reducing pain in those who suffer from arthritis by helping to cushion the bones against further damage. Like the other muscles of the hip, the gluteus medius is made up of many individual fibers that are attached at both ends. These fibers are capable of contracting or relaxing independently, which allows them to respond individually to different movements that demand increased strength or endurance. For example, if you are standing with balanced weight on both feet, the majority of the fibers in the gluteus medius will be relaxed.