Teun Remmers

158 | Chapter 9 Results Participant characteristics and development of total PA In total, 89 boys and 86 girls from 19 primary and 10 secondary schools provided valid data. Children were averagely aged 12.1 (SD=0.44) years old at baseline. Results from an electronic questionnaire administered directly after accelerometry (response rate 77% and 75% for the children and parents, respectively), showed that parents from participating children had relatively high socio-economic status; 72% with secondary vocational or higher educational diploma, and 67.9% with a paid job for at least three days per week. On average, children lived 620 (SD=571) meters from their primary school, and 3127 (SD=1976) meters from their secondary school. The distance of children’s home to their secondary school is on average 2506 meters further (SD=2014), compared to the distance to their primary school. In Table 1, we describe the change of total PA from primary to secondary school. It can be observed that LPA and MVPA increased before school time from primary to secondary school. In contrast, considerable declines were found after school and in weekend days. At baseline, girls seemed to be less active during school time compared to boys. However, after school, girls spent more time in LPA, whereas boys spent more time in MVPA. At follow-up boys spent more MVPA minutes at school and after school, whereas girls spent more LPA minutes before school and after school. Sedentary time increased during all time-segments except before school (Table 1).