Children's out-of-school independently mobile trips, active travel, and physical activity: A cross-sectional examination from the kids in the city study

Background: The study aim was to determine the association between children's objectively assessed moderate-to-vigorous physical activity (MVPA) and active trips (AT) and independently mobile trips (IM) during out-of-school hours. Methods: Children aged 9 to 13 years (n = 254) were recruited from 9 schools in Auckland, New Zealand between 2011 and 2012. Children completed travel diaries and wore accelerometers for 7 days. Parents provided demographic information. Geographic information systems-derived distance to school was calculated. Accelerometer data were extracted for out of school hours only. Percentage of time spent in MVPA (%MVPA), AT, and IM were calculated. Generalized estimating equations were used to determine the relationship between daily %MVPA and AT and between daily %MVPA and IM, accounting for age, sex, ethnicity, distance to school, day of the week, and numeric day of data collection. Results: A significant positive relationship was observed between %MVPA and both AT and IM. For every unit increase in the daily percentage of trips made that were AT or IM, we found an average increase of 1.28% (95% CI 0.87%, 1.70%) and 1.15% (95% CI 0.71%, 1.59%) time in MVPA, respectively. Conclusion: Children's AT and IM are associated with increased MVPA during out-of-school hours