Fitness, fatness and the reallocation of time between children’s daily movement behaviours: an analysis of compositional dataReport as inadecuate




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International Journal of Behavioral Nutrition and Physical Activity

, 14:64

First Online: 10 May 2017Received: 16 December 2016Accepted: 27 April 2017DOI: 10.1186-s12966-017-0521-z

Cite this article as: Fairclough, S.J., Dumuid, D., Taylor, S. et al. Int J Behav Nutr Phys Act 2017 14: 64. doi:10.1186-s12966-017-0521-z

Abstract

BackgroundMovement behaviours performed over a finite period such as a 24 h day are compositional data. Compositional data exist in a constrained simplex geometry that is incongruent with traditional multivariate analytical techniques. However, the expression of compositional data as log-ratio co-ordinate systems transfers them to the unconstrained real space, where standard multivariate statistics can be used. This study aimed to use a compositional data analysis approach to examine the adiposity and cardiorespiratory fitness predictions of time reallocations between children’s daily movement behaviours.

MethodsThis study used cross-sectional data from the Active Schools: Skelmersdale study, which involved Year 5 children from a low-income community in northwest England n = 169. Measures included accelerometer-derived 24 h activity sedentary time ST, light physical activity LPA, moderate-to-vigorous physical activity MVPA, and sleep, cardiorespiratory fitness determined by the 20 m shuttle run test, objectively measured height, weight and waist circumference from which zBMI and percent waist circumference-to-height ratio %WHtR were derived and sociodemographic covariates. Log-ratio multiple linear regression models were used to predict adiposity and fitness for the mean movement behaviour composition, and for new compositions where fixed durations of time had been reallocated from one behaviour to another, while the remaining behaviours were unchanged. Predictions were also made for reallocations of fixed durations of time using the mean composition of three different weight status categories underweight, normal-weight, and overweight-obese as the starting point.

ResultsReplacing MVPA with any other movement behaviour around the mean movement composition predicted higher adiposity and lower CRF. The log-ratio model predictions were asymmetrical: when time was reallocated to MVPA from sleep, ST, or LPA, the estimated detriments to fitness and adiposity were larger in magnitude than the estimated benefits of time reallocation from MVPA to sleep, ST or LPA. The greatest differences in fitness and fatness for reallocation of fixed duration of MVPA were predicted at the mean composition of overweight-obese children.

ConclusionsFindings reinforce the key role of MVPA for children’s health. Reallocating time from ST and LPA to MVPA in children is advocated in school, home, and community settings.

KeywordsSedentary time Physical activity Accelerometer LPA MVPA Sleep AbbreviationsCRFCardiorespiratory fitness

ENMOEuclidean norm minus one

IMDIndices of multiple deprivation

LPALight physical activity

MVPAModerate-to-vigorous- physical activity

STSedentary time

WHtRWaist-to-height-ratio

zBMIBody mass index z-score

Electronic supplementary materialThe online version of this article doi:10.1186-s12966-017-0521-z contains supplementary material, which is available to authorized users.





Author: Stuart J. Fairclough - Dorothea Dumuid - Sarah Taylor - Whitney Curry - Bronagh McGrane - Gareth Stratton - Carol Maher -

Source: https://link.springer.com/







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