Standing versus sitting classes: impact on sedentary behavior and physical activity in the school time and in the extra-school domains

Background Although classroom standing desks have been showing promising results, their effectiveness to reduce sedentary behavior during the school time and the potential impact on the extra-school context are still unclear. Methods Seventeen 6th grade students completed both sedentary behavior (ActivPAL inclinometer) and physical activity (Actigraph GT3X + accelerometer) assessments at baseline (sitting classes) and during weeks in which chairs were removed from the classroom and stand-up desks were introduced in the classroom (standing classes). Results Standing classes reduced sitting time (-106.9 min/9h; p < 0.05) and increased standing time (+ 104.54 min/9h; p < 0.05) in school hours but also in the whole weekdays (-107.4 min/15h of sitting and + 100.5 min/15h of standing; p < 0.05). A small but significant reduction in standing time was observed during the weekend (-15.4 min/14h). No differences in physical activity outcomes were found. Conclusions Our findings suggest that introducing standing desks within the school context, not only reduced adolescents’ sitting time while at the classroom, as no compensatory increase in sitting time was found outside the school context (i.e., weekday and weekend days). Finally, our investigation highlights that the choice of the method to evaluate these behavioral modifications is paramount, as the inclinometer was able to detect changes between conditions, while the accelerometer was not. ClinicalTrials.gov Identifier : NCT03137836 registered on May 3, 2017.