ORIGINAL ARTICLES  PHYSIOLOGY AND BIOMECHANICS 

The Journal of Sports Medicine and Physical Fitness 2012 April;52(2):115-21

Copyright © 2012 EDIZIONI MINERVA MEDICA

lingua: Inglese

Importance of epoch length and registration time on accelerometer measurements in younger children

Dencker M. ^{1, 2}, Svensson J. ², El-Naaman B. ², Bugge A. ², Andersen L. B. ^{2, 3} ✉

¹ Department of Clinical Sciences, Unit of Clinical Physiology and Nuclear Medicine, Skåne University Hospital, Lund University, Malmö, Sweden; ² Center for Research in Childhood Health, Institute of Sport Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark; ³ Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway

AIM: The aim of this study was to investigate the effect of epoch length on accumulation of minutes of physical activity per day over a spectrum of intensities, and the effect that selection of number of hours of acceptable registration required per day had on number of days that were considered acceptable.
METHODS: Participants were 696 children (369 boys and 327 girls) aged 6.7±0.4 yrs, from a population-based cohort. Physical activity was assessed by the Actigraph accelerometer for four days.
RESULTS: Main findings were that epoch length had a profound impact on accumulation of minutes of physical activity per day for higher intensities, whereas it had no effect on mean counts per minute. The chosen number of hours for an acceptable registration per day heavily influenced the number of days that were considered acceptable.
CONCLUSION: The findings in the present investigation should be taken into consideration when planning objective measurements of daily physical activity in younger children, and highlight the need for setting international recommendations for physical activity measurements with accelerometers, if different studies are to be comparable.