Abstract: AIMS: Dancers need to constantly maintain and develop their physiological capabilities to support their performances. Previously these physiological demands have been investigated only in traditional dance styles such as ballet and modern. The aim of this study was to examine the physiological demands of two types of hip-hop: new style and break dance. METHODS: Nine female new style dancers (age 20±6 yrs, height 163.5±1.4 cm, mass 55.8±22 kg) and 9 male break dancers (age 23±4.2 yrs, height 178.2±5.7 cm, mass 62.1±7.7 kg) volunteered for the study. Each subject completed a maximal graded treadmill test and a dance performance routine, either new style (approx 1:45-2:30 min) or breaking (2 min). Breathe-by-breathe gas analysis and heart rate (HR) were collected by a portable gas analyser, and blood lactate (BLa) was measured at the end of the treadmill test and each routine. RESULTS: The male breaker dancers had significantly higher VO2 peak than other equivalent dancers in other genres, whilst the female new style dancers were similar to that previously reported for female dancers. Performance data showed significant differences between the two styles for VO2, HR, and BLa (p<0.001) and for VO2 and HR relative to individual maximal treadmill data (p<0.05). CONCLUSION: New style is more comparable to other theatrical dance genres, with a lower relative mean VO2 demand, whilst break dance is shorter in duration, allowing a higher cardiorespiratory demand and generating significant levels of blood lactate. This difference is also reflected in the dancers' cardiorespiratory profiles.