Effects of the 3-year Sigue la Huella intervention on sedentary time in secondary school students.

Abstract

To examine the effects of the Sigue la Huella (Follow the Footstep) intervention on adolescents' daily sedentary time (ST). This quasi-experimental, cohort study took place in four secondary schools in Huesca (Spain) during the 2009-2010, 2010-2011 and 2011-2012 academic years (students aged 12-15 years). Two schools were assigned to the experimental condition (n = 368) and two schools to the control condition (n = 314). Sigue la Huella adopted a whole school approach and used both curricular and non-curricular intervention channels to empower students to make better decisions. ST was measured for 7 days on four occasions using accelerometers. Growth curve models were used to analyze the data. In the model with all participants, a significant interaction indicated that the effect of the intervention was dependent on the study cohort considered. While in cohort 1 there were no significant differences in rate of linear change of ST between the experimental and the control group (P = 0.148), in cohorts 2 and 3 significant differences were observed in favor of the experimental group (β = -13.88, 95% CI = -25.00 to -2.76, P = 0.015; β = -76.73, 95% CI = -110.68 to -42.78, P < 0.001), independent of type of school (public vs. private) and gender. Sigue la Huella had mainly a protective effect in two of the three study cohorts. Whereas in cohort 2 the intervention prevented increases in ST, in cohort 3 the intervention reduced considerably the increase in ST noted in the control group.