Pilates is a physical fitness system that strengthens and tones the core muscles -- primarily the abdominals, buttocks, and back. These are deep muscles that lie close to the spine and work to support and stabilize it. When these "Powerhouse" muscles as Joseph Pilates called them are strong, they keep the body balanced and in good posture. Weak core muscles can keep joints from aligning properly and can cause pain. Pilates called his method Contrology because he believed his method used the mind to control the muscles. A Pilates program includes awareness of the breath, as well as centering, control, concentration, flow and precision of movement.