As western theatrical dance has developed through the centuries, dance educators, artists, and researchers have sought methods to improve dance skills and to refine the quality of dance performance. In the pursuit of ever-increasing technical skills, improved alignment, freedom from injury, and enhanced artistic capabilities such as expanded dynamic and expressive range, dancers have explored numerous training systems developed for these purposes. These systems are often used in conjunction with dance technique classes, and they explore a range of approaches addressing different aspects of the neural and motor mechanisms underlying dance skills. In general, the systems can be seen as operating within two large concerns. The first includes systems using imagery and/or mental practice designed to affect alignment and dance performance on the subcortical or neurological level, with minimal or no physical action (Bartenieff 1980; Dowd 1990; Sweigard 1974; Todd 1937). The second emphasizes consistent and specialized exercise programs designed to encourage muscular strength and endurance, flexibility, and/or cardio-respiratory endurance, with the claim that these physical changes will enhance alignment, dance technique, and performance (Clippinger-Robertson 1990; Fitt 1988; Kravitz 1990; Lauffenburger 1990; Pilates 1945; Russell 1992; Solomon 1990; Stephens 1990; Trepman, Walaszek, & Micheli 1990). While there is often overlap in these two categories, the first group emphasizes neuromuscular repatterning to alter alignment or movement habits, while the second addresses muscular/structural alterations to affect change. For example, the body therapies, including the work of Bartenieff, Alexander, Feldenkrais, and Sweigard, attempt to alter the way muscles pattern themselves, stressing whole body activity, connections, and awareness, not exercises for specific muscles (Myers 1980). Conditioning programs, on the other hand, do engage particular muscles, in order to make gains in muscular strength and range of motion.