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Tracking of accelerometry-measured physical activity during childhood: ICAD pooled analysis

Soyang Kwon1*, Kathleen F Janz23 and on behalf of the ICAD Collaborators

Author Affiliations

1 Consortium to Lower Obesity in Chicago Children, Children’s Memorial Hospital, 2300 Children's Plaza, Box #157, Chicago, IL, 60614, USA

2 Departments of Health and Human Physiology, University of Iowa, E130 Field House, Iowa City, IA, 52242, USA

3 Epidemiology, University of Iowa, E130 Field House, Iowa City, IA, 52242, USA

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International Journal of Behavioral Nutrition and Physical Activity 2012, 9:68  doi:10.1186/1479-5868-9-68

Published: 7 June 2012



Understanding of physical activity (PA) tracking during childhood is important to predict PA behaviors and design appropriate interventions. We compared tracking of PA according to PA level and type of day (weekday/weekend) in a pool of five children’s cohort studies.


Data from ALSPAC, CLAN, Iowa Bone Development Study, HEAPS, PEACH were extracted from the International Children’s Accelerometry Database (ICAD), resulting in 5,016 participants with age, gender, and accelerometry data at both baseline and follow-up (mean age: 10.3 years at baseline, 12.5 years at follow-up). Daily minutes spent in moderate- and vigorous-intensity PA (MVPA) and vigorous-intensity PA (VPA) was categorized into quintiles. Multinomial logistic regression models were fit to predict follow-up (M)VPA from baseline (M)VPA (reference: 20- < 80%tile), age at follow-up, and follow-up duration.


For the weekday, VPA tracking for boys with high baseline VPA was higher than boys with low baseline VPA (ORs: 3.9 [95% CI: 3.1, 5.0] vs. 2.1 [95% CI: 1.6, 2.6]). Among girls, high VPA was less stable when compared low VPA (ORs: 1.8 [95% CI: 1.4, 2.2] vs. 2.6 [95% CI: 2.1, 3.2]). The pattern was similar for MVPA among girls (ORs: 1.6 [95% CI: 1.2, 2.0] vs. 2.8 [95% CI: 2.3, 3.6]). Overall, tracking was lower for the weekend.


PA tracking was higher on the weekday than the weekend, and among inactive girls than active girls. The PA “routine” of weekdays should be used to help children establish healthy PA patterns. Supports for PA increase and maintenance of girls are needed.

Stability; Objective measure; Exercise; Adolescents; Longitudinal