Preschool children's physical activity intensity during school time: Influence of school schedule

Chile's Physical Activity Report Card graded the overall index on PA behavior with an F The Ministry of Sports is implementing since 2014 "Jardín Activo" (JA program) which recommends 3 weekly teacher-led PE lessons for preschool children, on half or full day attendance. We determined the effectiveness of the JA program (contribution to MVPA during school time) and assessed if effectiveness varied according to schedule. 596 five y olds, (50% boys) were selected from 66 schools; 52.9% attended half day and 47.1% full day. Children wore accelerometers during school time a day with and one without PE lesson (JA day/non JA day). We compared PA intensity between both these days by gender, using descriptive statistics and t-tests and determined the differential effect on PA intensity, between non JA and JA days by school schedule, using mixed models analyses We compared β of sedentary and of MVPA by schedule with t-tests. Significant differences were found in PA intensity between both days within each gender. Minutes being sedentary were significantly less during JA days (14 and 15 min in boys and girls respectively); MVPA significantly higher in JA days (11 and 10 min respectively). % time children were sedentary and % they engaged in MVPA differed by schedule. Sedentary minutes were significantly higher (β - 16.2 vs - 13.2) in half day, while the increase in MVPA was significantly higher (β 12.5 vs 9.7) in full day. The JA program is effective, especially when children attend school full time.