Accelerometers and questionnaires in the study of physical activity and sedentary behaviour

Abstract

Problem: It is important to know the levels of physical activity and sedentary time of people to be able to perform interventions in order to improve lifestyles. Therefore, it is interesting to compare how the physical activity, mass-used and low-cost questionnaires perform, with the accelerometers that provide objective measurements.Objective: to compare physical activity and sedentary time in a group of adults measured by accelerometry and estimated through what was reported in a self-reported physical activity questionnaire. Methods: 12 men and 17 women, mean age of 34.14 years (9.46DS). Accelerometry: each subject carried, at the level of the right hip and secured with a belt, a CSA 7164 uniaxial accelerometer for a week and completed the Global Physical Activity Questionnaire (GPAQ), proposed by the World Health Organization. Results: the t-test of related samples was used showing that there are significant differences between the average sedentary time measured with the accelerometer and with the questionnaire, (p = 0.00). The Wilcoxon test compared the physical activity measured with the accelerometer and with the questionnaire that showed significant differences (p = 0.009). A weak positive correlation (r = 0.45) in time (p = 0.014) could be observed, meaning that both devices register it with the same trend. Conclusion: Care must be taken when interpreting the results of physical activity questionnaires since in general they may present significantly different values ​​than those reported by objective methods. It is necessary to improve the questionnaires, or their interpretation.