Development and psychometric evaluation of a health questionnaire on back care knowledge in daily life physical activities for adolescent students

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. 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. Cronbach's alpha (alpha = 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. The questionnaire showed acceptable psychometric values. Results showed that this questionnaire is a good instrument to assess adolescent's back care knowledge.