VALIDITY OF THE PHYSICAL ACTIVITY BEHAVIOR QUESTIONNAIRE (QCAF) AMONG HEALTHY AND UNHEALTHY INDIVIDUALS

Aim: The aim of this study was to test the convergent and divergent validity of the Physical Activity Behavior Questionnaire (QCAF, acronym in Portuguese for Questionário do Comportamento de Atividade Física), an instrument developed based on the Theory of Planned Behavior.

Methods: An exploratory study was conducted in an outpatient clinic among 236 individuals referred for cardiopulmonary exercise testing with oxygen uptake. Coronary heart disease, hypertensive and healthy individuals were enrolled. PA was measured by the QCAF and the Baecke Habitual PA Questionnaire (Baecke-HPA). Cardiorespiratory fitness was estimated by the Veterans Specific Activity Questionnaire (VSAQ), the peak (VO_2peak) and the maximum oxygen uptake (VO_2max).

Results: The convergent validity was verified by the confirmed relation between the QCAF and the measures of physical activity – Baecke-HPA (r_adj=0.32; p<0.0001) and cardiorespiratory fitness – VO_2peak (r_adj=0.15; p=0.02), VO_2max (r_adj=0.13; p=0.05) and VSAQ (r_adj=0.13; p=0.05). The divergent validity was confirmed by the absence of significant correlations between the QCAF and the Occupational Physical Activity domain of the Baecke-HPA (r=0.04; p=0.49), as expected.

Conclusion: The QCAF presented acceptable levels of convergent and divergent validity, demonstrating to be a useful tool in order to measure walking among a diverse adult population.