Definitions of adherence, also termed compliance, with use of hip protectors have varied in published studies, making interpretation of results difficult. This paper proposes standard definitions of adherence with the use of hip protectors. Adherence is the wearing of hip protectors in accordance with the recommendations of the study protocol, and is measured as the amount of time hip protectors are worn. When reporting use of hip protectors in clinical trials investigators should indicate the specific definition of adherence used, explicitly state the recommendation that was made for use of hip protectors during the study, and describe the methods of recording adherence.