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dc.contributor.authorRicardo, Luiza Isnardi Cardoso
dc.contributor.authorWendt, Andrea
dc.contributor.authorGalliano, Leony Morgana
dc.contributor.authorde Andrade Muller, Werner
dc.contributor.authorNiño Cruz, Gloria Izabel
dc.contributor.authorWehrmeister, Fernando
dc.contributor.authorBrage, Soren
dc.contributor.authorEkelund, Ulf
dc.contributor.authorCrochemore M. Silva, Inácio
dc.description.abstractPurpose: The present study aims to estimate the minimum number of accelerometer measurement days needed to estimate habitual physical activity (PA) among 6- (2010), 18- (2011) and 30- (2012) year-old participants, belonging to three population-based Brazilian birth cohorts. Method: PA was assessed by triaxial wrist-worn GENEActiv accelerometers and the present analysis is restricted to participants with at least 6 consecutive days of measurement. Accelerometer raw data were analyzed with R-package GGIR. Description of PA measures (overall PA, moderate-to-vigorous PA (MVPA), light PA (LPA)) on weekdays and weekend days were conducted, and statistical differences were tested with chi-squared and Kruskal-Wallis tests. Spearman Brown Formulae was applied to test reliability of different number of days of accelerometer use. Results: Differences between week and weekend days regarding LPA, MVPA and overall PA, were only observed among 30-year-olds. Higher levels of MVPA (p = 0.006) and overall PA (p<0.001) were identified on weekdays. For overall PA, to achieve a reliability coefficient >0.70, two and three days of measurement were needed in adults and children, respectively. For LPA, a reliability coefficient >0.70 was achieved with five days in 6-year-old children, three days in 18-year-old young adults, and four days in 30-year-old adults. Considering MVPA, four days would be necessary to represent a week of measurement among all cohort groups. Conclusion: Our results show that four and five measurement days are needed to estimate all habitual PA constructs, for children and adults, respectively. Also, among 30-year-old adults, it is important to make efforts towards weekend days measurement.
dc.rightsAttribution 4.0 International (CC BY 4.0)en
dc.subjectResearch Article
dc.subjectEngineering and technology
dc.subjectMedicine and health sciences
dc.subjectResearch and analysis methods
dc.subjectBiology and life sciences
dc.subjectPeople and places
dc.titleNumber of days required to estimate physical activity constructs objectively measured in different age groups: Findings from three Brazilian (Pelotas) population-based birth cohorts
datacite.contributor.supervisoreditor: Naugle, Kelly
dc.contributor.orcidRicardo, Luiza Isnardi Cardoso [0000-0002-1244-4501]
dc.contributor.orcidGalliano, Leony Morgana [0000-0002-5599-0377]
dc.contributor.orcidNiño Cruz, Gloria Izabel [0000-0002-4951-5991]
pubs.funder-project-idWellcome Trust (GR 72403MA)
pubs.funder-project-idWellcome Trust (086974/Z/08/Z)

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Attribution 4.0 International (CC BY 4.0)
Except where otherwise noted, this item's licence is described as Attribution 4.0 International (CC BY 4.0)