RESUMO
PURPOSE: The most relevant musculoskeletal problems are related with back health. Study instruments have been designed for adult patient population but not for school-aged children. The aim of this study was to develop and evaluate the psychometric properties of a questionnaire to assess adolescents' level of back care knowledge in daily life physical activities. METHODS: Participants were 171 adolescents from secondary schools. The questionnaire was made up of 24 questions. A Delphi method was used for test validation. Cronbach's alpha, test-retest, Wilcoxon signed-rank and Bland-Altman graph were used to evaluate the instrument reliability. RESULTS: Cronbach's alpha (α = 0.82) showed a strong internal consistency. Test-retest was excellent for total score (0.76) and moderate to excellent (0.54-0.76) for seven score conceptual categories with good results of standard error of the mean and minimal detectable change. No differences were found between test 1 and test 2 except for the standing posture scores. CONCLUSION: The questionnaire showed acceptable psychometric values. Results showed that this questionnaire is a good instrument to assess adolescent's back care knowledge.