Reliability and validity of the Activity Questionnaire for Adults and Adolescents (AQuAA)

In the test-retest reliability study, 53 adolescents and 58 adults completed the AQuAA twice, with an interval of two weeks. In the validity study, 33 adolescents and 47 adults wore an accelerometer (Actigraph) during two weeks, and subsequently completed the AQuAA.In adolescents the test-retest reliability was fair to moderate (intraclass correlations (ICCs) ranging from 0.30 to 0.59). In adults the test-retest reliability was fair to moderate for the time spent on sedentary, light and moderate intensity activities (ICCs ranging from 0.49 to 0.60), but poor for time spent on vigorous activities (ICC = -0.005). The correlations between the AQuAA and Actigraph were low and nonsignificant. Compared with the Actigraph, time spent on all physical activities was significantly higher according to the questionnaire (except for light intensity activities in adolescents), while time spent on sedentary behaviours was significantly lower.Reliability of the AQuAA is fair to moderate. The validity of the AQuAA compared to an accelerometer is poor. Both adolescents and adults underestimate the time spent on sedentary behaviours and overestimate the time spent on physical activities.Physical activity is an important behaviour related to a number of health outcomes. Accurate assessment of physical activity levels is important to understand the association between physical activity and health, but also to monitor secular trends in behaviour and to evaluate the effectiveness of interventions and programs [1]. However, valid and appropriate assessment of physical activity (PA) is a challenging task. First, since PA behaviour varies considerably within and among individuals and populations. Second, there are several health-related dimensions of PA, such as caloric expenditure, aerobic intensity, weight bearing, flexibility, and strength [2,3].Epidemiological studies have typically used subjective measures, such as the questionnaire, to assess PA in populations. PA questionnaires are ea