Reformer Core targets the core muscles. Core muscles include the abdominal muscles, back muscles and the muscles around the pelvis. The core muscles really are the foundation of the human body. And much like building a house, when it comes to fitness, you need to start with a strong foundation. This leads to better balance and steadiness, also called stability. Stability is important whether you're on the playing field or doing regular activities. In fact, most sports and other physical activities depend on stable core muscles. Benefits: improve posture improves balance improve stability releaves back pain intensity tones and stregthens abdominals