Improving the identification of bone-specific physical activity using wrist-worn accelerometry: A cross-sectional study in 11-12-year-old Australian children

Gemma Brailey, Sean Cumming, Brad Metcalf, Lisa Price, Timothy Olds, Peter Simm, Melissa Wake, Victoria Stiles

Research output: Contribution to journalArticlepeer-review

Abstract

Physical activity (PA) during childhood and adolescence is important for the accrual of maximal peak bone mass. The precise dose that benefits bone remains unclear as methods commonly used to analyze PA data are unsuitable for measuring bone-relevant PA. Using improved accelerometry methods, this study identified the amount and intensity of PA most strongly associated with bone outcomes in 11–12-year-olds. Participants (n = 770; 382 boys) underwent tibial peripheral quantitative computed tomography to assess trabecular and cortical density, endosteal and periosteal circumference and polar stress-strain index. Seven-day wrist-worn raw acceleration data averaged over 1-s epochs was used to estimate time accumulated above incremental PA intensities (50 milli-gravitational unit (mg) increments from 200 to 3000 mg). Associations between time spent above each 50 mg increment and bone outcomes were assessed using multiple linear regression, adjusted for age, sex, height, weight, maturity, socioeconomic position, muscle cross-sectional area and PA below the intensity of interest. There was a gradual increase in mean R2 change across all bone-related outcomes as the intensity increased in 50 mg increments from >200 to >700 mg. All outcomes became significant at >700 mg (R2 change = 0.6%–1.3% and p = 0.001–0.02). Any further increases in intensity led to a reduction in mean R2 change and associations became non-significant for all outcomes >1500 mg. Using more appropriate accelerometry methods (1-s epochs; no a priori application of traditional cut-points) enabled us to identify that ∼10 min/day of PA >700 mg (equivalent to running ∼10 km/h) was positively associated with pQCT-derived measures of bone density, geometry and strength in 11–12-year-olds.
Original languageEnglish
Pages (from-to)987-998
Number of pages12
JournalEuropean Journal of Sport Science
Volume24
Issue number7
Early online date4 May 2024
DOIs
Publication statusPublished - 31 Jul 2024

Data Availability Statement

The LSAC and CheckPoint data are available under licence at https://growingupinaustralia.gov.au/data-and-documentation/accessing-lsac-data. To access raw accelerometry data, please contact the MCRI’s LifeCourse initiative https://lifecourse.melbournechildrens.com

Funding

This article uses unit record data from Growing Up in Australia, the Longitudinal Study of Australian Children (LSAC). The study is conducted in partnership between the Department of Social Services, the Australian Institute of Family Studies and the Australian Bureau of Statistics. The findings and views reported in this paper are solely those of the authors. Research Electronic Data Capture (REDCap) tools were used in this study (Harris et al., 2009 , 2019 ). More information about this software can be found at: www.project\u2010redcap.org . The authors would like to thank the LSAC and CheckPoint study participants, staff and students for their contributions. GB was supported by the Economic and Social Research Council. AR is supported by the NIHR Leicester Biomedical Research Centre, and the Collaboration for leadership in Applied Health Research and Care (CLAHRC) East Midlands. The views expressed are those of the authors and not necessarily those of the NHS, NIHR or Department of Health. MW was supported by NHMRC Principal Research Fellowship 1160906. The CheckPoint study was supported by the Australian National Health and Medical Research Council (NHMRC) Project Grants [1041352 and 1109355]; The Royal Children's Hospital Foundation [2014\u2010241]; the Murdoch Children's Research Institute; The University of Melbourne; the National Heart Foundation of Australia [100660]; the Financial Markets Foundation for Children [2014\u2010055 and 2016\u2010310] and the Victorian Deaf Education Institute. Research at the Murdoch Children's Research Institute is supported by the Victorian Government's Operational Infrastructure Support Programme. The funding bodies did not play any role in the study design, collection, analysis, and interpretation of data, writing of the manuscript, or in the decision to submit for publication. For the purpose of open access, the author has applied a \u201CCreative Commons Attribution (CC BY) license\u201D to any Author Accepted Manuscript version arising.

FundersFunder number
Economic and Social Research Council
Murdoch Children’s Research Institute
University of Melbourne
State Government of Victoria
NIHR Leicester Biomedical Research Centre
Victorian Deaf Education Institute
Operational Infrastructure Support Programme
National Health and Medical Research Council1109355, 1041352, 1160906
National Health and Medical Research Council
National Heart Foundation of Australia100660
National Heart Foundation of Australia
Financial Markets Foundation for Children2014‐055, 2016‐310
Financial Markets Foundation for Children
Royal Children's Hospital Foundation2014‐241
Royal Children's Hospital Foundation

Keywords

  • accelerometry
  • adolescents
  • bone health
  • cross-sectional studies
  • physical activity

ASJC Scopus subject areas

  • Physical Therapy, Sports Therapy and Rehabilitation
  • Orthopedics and Sports Medicine

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