Changes in time-segment specific physical activity between ages 10 and 14 years: A longitudinal observational study

• Published in: Journal of science and medicine in sport 2016-01, Vol.19 (1), p.29-34
• Main Authors: Brooke, Hannah L, Atkin, Andrew J, Corder, Kirsten, Ekelund, Ulf, van Sluijs, Esther M.F
• Format: Article
• Language: English
• Subjects: Accelerometry; Adolescent; Adolescent Behavior; Adolescents; Child; Child Behavior; Child development; Children & youth; Collaboration; Councils; Data collection; Data processing; Epidemiology; Exercise; Female; Funding; Humans; Intervention; Leisure Activities; Longitudinal Studies; Male; Medical research; Original Research; Patterns; Physical Medicine and Rehabilitation; Public health; Schools; Social research; Sports Medicine; Studies; Time-segments
• ISSN: 1440-2440; 1878-1861; 1878-1861
• DOI: 10.1016/j.jsams.2014.10.003

Abstract Objectives Describe (1) time-segment specific changes in physical activity (PA) into adolescence, (2) differences in change in PA between specific time-segments (weekdays–weekends, in-school–out-of-school, out-of-school–weekends, lesson-time–lunch-time), and (3) associations of change in time-segment specific with overall PA. Design Longitudinal observational study (4-year follow-up). Methods Children from the SPEEDY study ( n = 769, 42% boys) had PA measured by accelerometer for at least three days at ages 10.2 ± 0.3, 11.2 ± 0.3 and 14.3 ± 0.3 years. Changes in moderate-to-vigorous PA (ΔMVPA, minutes ≥2000 counts/minute [cpm]) and total PA (ΔTPA, average cpm) during weekdays, weekends, in-school, out-of-school, lesson-times and lunch-times, were tested using three level (age, individual, school) mixed-effects linear regression. Differences in ΔMVPA/ΔTPA between time-segments were tested using time-segment × age interaction terms. Associations of four-year time-segment specific ΔMVPA/ΔTPA with four-year overall ΔMVPA/ΔTPA were tested using two level (time-segment specific ΔMVPA/ΔTPA, school) mixed-effects linear regression. Results MVPA and TPA declined in all time-segments, except lesson-time MVPA. Annual ΔMVPA and, for boys only, ΔTPA was greater on weekends than weekdays (beta ± SE for interaction term: boys, −3.53 ± 0.83 min, −29.64 ± 7.64 cpm; girls, −2.20 ± 0.64 min) and out-of-school (boys, −4.36 ± 0.79 min, −19.36 ± 8.46 cpm; girls, −2.44 ± 0.63 min). ΔMVPA and ΔTPA during lunch-time was greater than during lesson-time (boys, −0.96 ± 0.20 min, −36.43 ± 6.55 cpm; girls, −0.90 ± 0.13 min, −38.72 ± 4.40 cpm). ΔTPA was greater out-of-school than in-school (boys, −19.89 ± 6.71 cpm; girls, −18.46 ± 6.51 cpm). For all time-segments, four-year ΔMVPA/ΔTPA was positively associated with four-year overall ΔMVPA/ΔTPA (all p < 0.042), except for girl's in-school and lunch-time TPA. Conclusions Interventions focused on PA maintenance could target all time-segments, but weekends and out-of-school may be particularly advantageous due to the relatively large declines observed.