As classical ballet is an aesthetic art form, physiological characteristics of professional dancers such as flexibility are often dictated, albeit indirectly, by artistic directors or choreographers. However, the most aesthetically desirable dancers may not be the most durable. In order to test these hypotheses, several initial studies were carried out. Video analysis concluded that classical ballet is a high intensity, intermittent form of exercise, at performance level, but also found that different dancers within a company hierarchy worked at different intensities. The relationship between fitness components and performance proficiency in classical ballet indicated associations between high levels of performance proficiency and core stability, lower limb power and flexibility at the hip joint. Finally a 10-week fitness training programme showed that performance aesthetics significantly improved. In summary physical fitness is positively linked to performance proficiency in classical ballet.