• Physical activity in youth decreases with age, with the transition from primary to secondary school being a key period for change. Active travel to school has been associated with higher physical activity in youth compared with those who travel by car. This study investigated whether change in travel mode to/from school was associated with change in physical activity among young people transitioning from primary to secondary school.
• One thousand three hundred and seven final year UK primary school children (11.0 ± 0.4 yr) were recruited, of whom 953 (72.9%) were followed-up 1 year later in their first year of secondary school. Physical activity was measured by accelerometer, and travel mode to/from school was self-reported. Change in moderate-to-vigorous physical activity (MVPA) associated with change in travel mode between primary and secondary school was measured in 500 children who provided valid accelerometer data and used a consistent travel mode to/from school at each time point.
• Total MVPA was slightly higher in secondary school than primary school (60.6 ± 21.6 vs. 63.1 ± 23.6 min, respectively, P = 0.017). Daily MVPA increased by 11.4% in children who walked both to primary and secondary school (63.4 ± 22.0 vs. 70.6 ± 23.0 min, P < 0.001). In those who changed from walking to car travel, MVPA decreased by 15.5% (62.5 ± 22.0 vs. 52.8 ± 21.5 min, P = 0.003), whereas adoption of bus travel was associated with smaller reductions. A change from car travel to walking was associated with 16.1% more daily MVPA (50.1 ± 14.3 vs. 58.2 ± 20.6 min, P = 0.038).
• Change from active to passive transportation to school may contribute to the decline in physical activity seen between primary and secondary school.

Cooper, A. R., Jago, R., Southward, E. F., & Page, A. S. (2012). Active Travel and Physical Activity across the School Transition: the PEACH Project. Medicine & Science in Sports & Exercise, 44(10), 1890-1897. doi: 10.1249/MSS.0b013e31825a3a1e