Development and validation of a questionnaire measuring factors associated with physical activity in adolescents

objectives: to develop a questionnaire to measure factors associated with physical activity (pa) in adolescents and analyze its reliability and validity. methods: a total of 248 adolescents from 14 to 19 years old took part in this study. the factors associated with pa measured were: attitude, self-efficacy, social support of pa and perceived environment. cronbach's alpha (α) and intraclass correlation coefficients (icc) were used to test reliability, and exploratory factor analysis to evaluate validity. results: attitude was measured as a single factor (attitude: α=0.76, icc=0.89); self-efficacy consisted of two factors: resources for pa (α=0.76, icc=0.75) and social support and motives for engaging in pa (α=0.76, icc=0.67); social support was measured as two factors: support for pa from friends (α=0.90, icc=0.89) and support for pa from parents (α= 0.81, icc=0.91); and the environment was measured as three factors: access to and attractiveness of places to engage in pa (α=0.69, icc=0.82), security/safety when engaging in pa (α=0.73, icc=0.67), and general infrastructure of the neighborhood (α=0.70, icc=0.75). conclusions: the questionnaire exhibited satisfactory validity and reliability and can be recommended for studies investigating adolescents.