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Assessing volume of accelerometry data for reliability in preschool children
Trina Hinkley1, Eoin O'Connell, Anthony D Okely
1Interdisciplinary Educational Research Institute, University of Wollongong, Wollongong, New South Wales, Australia. trina.hinkley@deakin.edu.au
Medicine and Science in Sports and Exercise
|July 11, 2012
Summary
To reliably estimate preschool children's physical activity, collect at least 7 hours of accelerometry data daily for 3-4 days, including at least one weekend day. This ensures accurate physical activity measurement.
Area of Science:
- Pediatric physical activity research
- Biomedical data analysis
- Childhood obesity prevention
Background:
- Accurate measurement of physical activity in preschool children is crucial for health.
- Accelerometry is a common objective measure, but optimal data volume is debated.
Purpose of the Study:
- Determine the necessary volume of accelerometry data (hours per day and number of days) for reliable physical activity estimation in preschoolers.
- Investigate if including weekend data is essential for accurate assessment.
Main Methods:
- Utilized accelerometry data from 493-799 preschool children.
- Analyzed hourly increments of daily data to assess physical activity levels.
- Employed t-tests and Spearman-Brown prophecy formula to determine reliability and required data duration.
Main Results:
- Preschool children exhibit significantly higher physical activity levels on weekends compared to weekdays.
- More data per day (e.g., 10+ hours) requires fewer days (2.7-2.8) for a reliability estimate of 0.7.
- Fewer hours of data per day (e.g., 7 hours) necessitates more days (3.3-3.4) for the same reliability.
Conclusions:
- Future studies must collect sufficient accelerometry data (hours/day and days) to achieve at least 0.7 reliability.
- Inclusion of at least one weekend day is recommended for reliable physical activity estimation in preschool children.
- Reporting the achieved reliability level is essential for study transparency.
