Background Ballet dancers are both artists and athletes with extreme physical demands placed on them. Clinical experience and previous studies suggest that they are at high risk of sustaining injuries, but more high-quality prospective studies are needed.

Objective To assess the prevalence of injuries and illnesses among professional ballet dancers in the Norwegian National Ballet Company, using a newly developed injury surveillance method. Information gained may provide a foundation for future prevention interventions.

Design Prospective cohort study.

Participants A total of 57 dancers in the National ballet company agreed to participate. During the first 32 weeks of the registration there has been 5 drop-outs.

Interventions Every second week all dancers received a recently developed online questionnaire which records symptoms of illness and injury, as well as reduced participation and dancing performance due to health problems.

Main outcome measurements Prevalence of injuries and illnesses.

Results Preliminary results after 32 weeks. The average response rate was 81% (64–89%). The average injury prevalence was 64% (32–84%), and the average illness prevalence was 9% (4–20%). The prevalence of substantial injuries, defined as injuries leading to moderate or severe reductions in dance participation or performance, or total inability to dance, was 29% (18–45%). Thirty-four percent of injuries were located in the ankle, 18% in the lower leg, 12% in the knee and 11% in the foot.

Conclusions The prevalence of injury is extremely high among dancers at the Norwegian National Ballet Company, being considerably higher than among elite athletes from Olympic sports. Future efforts to prevent injuries in this group are warranted.