Background Basketball referees are responsible for rule length and decision making. They have high physical and psychological demand during the match.

Objective To understand the health problems of basketball officials, such as disorders or musculoskeletal injuries and their complaints.

Design Prospective cohort study.

Setting Referees of Basketball Federation of São Paulo.

Patients (or Participants) Initially, 78 referees were assessed, over 18 years old, both sexes and with more than 1 year of practice. Participants who refused to participate were not included, and participants who refused to stay in the study during follow-up were excluded. The participants number varied over the follow-up weeks, with at least 42 participants.

Interventions (or Assessment of Risk Factors) An initial assessment of the basketball referees was made at the annual physical assessment day of Basketball Federation of São Paulo and then they were followed online weekly for 12 weeks.

Main Outcome Measurements The initial assessment was made using an assessment form with personal data, practice and injury historic and knowledge about injury prevention. The weekly follow up was done using the questionnaire Oslo Sports Trauma Research Center (OSTRC) questionnaire to assess health problems.

Results Mean age was 36.5 (± 9.8) years, 66 (84.6%) were male. The most reported injuries by the referees in the 3 months prior the initial assessment were knee injuries (26.9%), mainly at the time of fitness training (65.4%). During the follow-up, musculoskeletal injuries had weekly mean prevalence of 17.4% (16.5 - 18.3) versus 3.2% (0.4 - 6.0) for illness. Regarding injuries, the ankle was the most affected region for acute injuries and the knee for overuse injuries.

Conclusions Basketball referees were mainly affected by lower limb injuries. Considering the injury profile and the prevalence of associated musculoskeletal complaints found in this study, it appears that injury prevention programmes should be developed and integrated into the fitness training routine of the referee.