title: Effects of the 3-year Sigue la Huella intervention on sedentary time in secondary school students.
abstract: BACKGROUND
  To examine the effects of the Sigue la Huella (Follow the Footstep) intervention on adolescents' daily sedentary time (ST).
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: 1 Facultad de Salud, Universidad San Jorge, Villanueva de Gállego, C.P. 50830, Zaragoza.
authors.forename: Berta
authors.initials: B
authors.lastname: Murillo Pardo
authors.affiliation: 2 Department of Kinesiology and Physical Education, McGill University, Montreal QC H2W 1S4, Canada.
authors.forename: Enrique
authors.initials: E
authors.lastname: García Bengoechea
authors.affiliation: 3 Departamento de Expresión Musical, Plástica y Corporal, Universidad de Zaragoza, Huesca C.P. 22002, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Generelo Lanaspa
authors.affiliation: 3 Departamento de Expresión Musical, Plástica y Corporal, Universidad de Zaragoza, Huesca C.P. 22002, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Zaragoza Casterad
authors.affiliation: 3 Departamento de Expresión Musical, Plástica y Corporal, Universidad de Zaragoza, Huesca C.P. 22002, Spain jajulian@unizar.es.
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Julián Clemente
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D002648:Child; D002652:Child Behavior; D015331:Cohort Studies; D015444:Exercise; D005260:Female; D006293:Health Promotion / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D015397:Program Evaluation / Q000379:methods / Q000706:statistics & numerical data*; D057185:Sedentary Behavior; D013030:Spain; D013334:Students / Q000706:statistics & numerical data*