Measurement of the temporal patterns of school bag carriage using activity monitoring and structured interview.

The primary objective of the current study was to quantify the temporal patterns of school bag carriage over an actual school day using activity monitoring and structured interviews, in order to better understand the physical demands of school bag carriage. The temporal patterns of 40 students' school bag carriage over a 24-h period were defined by total school bag carrying time, mean event school bag carrying time, the number of school bag carrying events, total carrying time travelling to and from school and the number of students who walked or used transport to travel to and from school. There were significant correlations between activity monitor [mean(SD) 119(48) min] and structured interview [100(39) min] determined total school bag carrying time (r = 0.59), activity monitor [8(4) min] and structured interview [9(4) min] determined mean event school bag carriage time (r = 0.65), and activity monitor [15(4) events] and structured interview [11(2) events] determined number of school bag carrying events (r = 0.52). However, the number of school bag carrying events, and for students who used transport, the total amount of time spent travelling to school was significantly different using the two measures. The durations of school bag carriage and the relationship between activity monitor and structured interview were similar to those reported in previous studies.