Quantifying physical activity during active commuting to school: A comparison of methodologies

• Accurate identification of start/end times is crucial for measuring physical activity during commuting accurately. • Common interval times may overestimate sedentary time and light physical activity during commuting. • Our proposed method, based on the distance from home to school, performed as well as GPS. The current study aims to detect walking trips to/from school with different methodologies (GPS, self-reported, fixed windows [w30 and w60], and distance-based time), and to compare the start/end times for the trips, and the time accumulated in sedentary time, light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA). A total of 93 Spanish adolescents wore an accelerometer and GPS during school days, and the start/end times of walking trips to/from school were determined using five different methodologies. Mixed-effects limits of agreement analyses were used to determine the level of agreement between the start/end times of the walking trips identified by the five methodologies mentioned. Moreover, methodologies were determined to be equivalent if the mean difference with the GPS was within the proposed equivalence zone of ± 5.0 min. Self-reported measures showed a good level of agreement for estimating start times of walking trips to school compared to GPS, 0.0 (LoA95%:-0.3–0.2) hours. Self-reported measures were deemed equivalent to GPS for measuring sedentary time, LPA, and MVPA. W30 and distance-based time were equivalent to GPS for LPA and MVPA, but not for sedentary time. W60 was only deemed equivalent to GPS for MVPA accumulated during walking trips to and from school. Self-reported measures showed the most precise approach for estimating start times to school, as well as it deemed equivalent to GPS for quantifying sedentary time, LPA, and MVPA. Moreover, estimating the time to complete the trip based on the distance between home and school could be more appropriate than fixed windows.