Comparisons of Subjective and Objective Measures of Free-Living Daily Physical Activity and Sedentary Behavior in College Students

Abstract

To compare physical activity and sedentary behavior between four commonly used subjective and objective measures: the 7-day Physical Activity Recall (7DPAR), International Physical Activity Questionnaire (IPAQ), pedometer, and accelerometer. A total of 130 college students completed four measures for the same 7 days. Body composition was measured using a bioelectric impedance analyzer. Wilcoxon signed rank tests and Spearman correlations were performed to compare estimates between activity measures. The Spearman correlations between different activity measures were further examined separately for the higher and the lower body fat groups. Compared with accelerometer-derived data, both the 7DPAR and the IPAQ overestimated light physical activity (P < 0.001) while underestimated sedentary behavior (P < 0.001). Across comparisons, the highest correlation was found between accelerometers and pedometers on steps/day (r = 0.72, P < 0.001). The 7DPAR and the IPAQ were correlated with each other for all physical activity variables and sedentary behavior (r = 0.37–0.45). There were low correlations (r = 0.20–0.47) between the 7DPAR, the IPAQ, and accelerometers in sedentary behavior, light physical activity, and vigorous physical activity. Higher correlations between different activity modalities were observed among individuals with lower body fat (r = 0.41–0.80) than among those with higher body fat (r = 0.31–0.65). The 7DPAR and the IPAQ yielded comparable estimation of moderate physical activity relative to accelerometers. There were significant differences in sedentary time across activity measures. Body compositions should be considered when comparing the estimates of activity levels between subjective and objective instruments.