Effect of a school-based multicomponent intervention on time-segmented physical activity and sedentary behavior among adolescents: a cluster randomized control trial

Abstract

Abstract Background Interventions have focused on evaluating effective strategies for increasing physical activity (PA) and reducing sedentary behavior (SB) in children and adolescents, which is still a challenge mainly in low- and middle-income countries. Thus, this study aimed to assess the effect of the Movimente Study on device-measured PA and SB in two-time segments of the school day amongst Brazilian adolescents. Methods Six elementary schools were randomized into the intervention (IG) or control group (CG). Participants were in 7th -9th grades. A school year (2017) multicomponent intervention was delivered consisting of three components: (1) teacher training, (2) education curriculum, and (3) school environment. PA and SB were assessed using GT3x + ActiGraph hip-worn accelerometers. The trial’s primary outcome was overall device-measured PA and SB. Exploratory secondary analyses examined PA and SB within in-School (08:00–11:59) and out-of-school (12:00–22:00) time segments. A two-level linear mixed model assessed the effect of the intervention on light-intensity PA (LPA), moderate- to vigorous-intensity PA (MVPA), SB, and MVPA/SB ratio within and between groups. Results There was a significant effect on the IG compared to the CG for MVPA (Coefficient [Coef.] = 16.2; 95% Confidence Interval [95%CI] = 6.9;25.5; p-value = 0.001), SB (Coef. = -22.7; 95%CI = -44.7;-0.7; p-value = 0.043), and MVPA/SB ratio (Coef. = 3.2; 95%CI = 1.2;5.3; p-value = 0.002) performed in the out-of-school segment, but not in the In-school segment. However, there were no significant differences within- nor between-group differences in LPA in both day segments. Conclusion The Movimente Study was associated with greater increases in MVPA, improvements in the MVPA/SB ratio, and reductions in SB during the out-of-school period compared with control peers. Trial registration Clinical Trials - NCT02944318. Registration Date: 10/24/2016.