Impact of prescribed exercise on physical activity compensation in young adults

Army Reserve Officers' Training Corps cadets present a unique subpopulation because they are required to participate in regular physical activity (PA). This study describes PA patterns of cadets and attempts to identify evidence of nonexercise PA compensation (activitystat) as a result of prescribed PA (pPA) by comparing differences between training and nontraining days for (a) autonomous PA among cadets and (b) PA between cadets and noncadets. Participants included 84 university students (33 cadets and 51 noncadets) who each wore an accelerometer for 5 consecutive days to estimate moderate and vigorous physical activity (MVPA). A 2×2 mixed model analysis of variance was used to examine within- and between-group differences in MVPA on training and nontraining days. This analysis was repeated after removing the cadet's pPA. Cadets had lower-body fat than noncadets (p = 0.044), but all other characteristics were similar. Overall, moderate PA (MPA) and vigorous PA (VPA) were significantly greater among cadets (p = 0.048 and p < 0.001), because of greater weekend MPA (p = 0.021) and greater weekday VPA (p < 0.001). Cadets accumulated more MVPA on training days than nontraining days (p < 0.001) and accumulated more MVPA than noncadets on training days (p = 0.004). However, after accounting for pPA, cadet MVPA did not differ between training and nontraining days (within 1.2Â ± 18.4 min·d -1) and was similar between cadets and noncadets (within 1.5Â ± 5.9 min·d -1). These results suggest that cadets were significantly more active than noncadets due mainly to pPA. When controlling for pPA, cadets were similarly active across all days, and were as active as noncadets, indicating no evidence of activitystat in this population.