Pilates helps more than your beauty, it works muscles in your core -- piriformis and gluteus medius -- that stabilize your pelvis and spine. Your gluteus medius is located on the side of your hip. It originates under the arching hip bone called the ilium and inserts on a knobby part, the trocanter, of your femur. Your piriformis muscle is deep underneath your buttocks. It orginates at your sacrum and sit bones and inserts at the posterior trochanter of your femur, or thigh bone.