Reproducibility of objectively measured physical activity: Reconsideration needed
- 1 January 2020
- journal article
- research article
- Published by Taylor & Francis Ltd in Journal of Sports Sciences
- Vol. 38 (10), 1132-1139
- https://doi.org/10.1080/02640414.2020.1743054
Abstract
Reliability of accelerometer-determined physical activity (PA), and thus the required length of a monitoring period, appears to depend on the analytic approach used for its calculation. We compared reliability of objectively measured PA using different resolution of data in a sample of 221 Norwegian 2-6-year-old children providing 2-3 valid 14-day periods of accelerometer monitoring (ActiGraph GT3X+) during September-October, January-February, and May-June 2015-2016. Reliability (intra-class correlation [ICC]) was measured for 1-14 days of monitoring across the measurement periods using linear mixed effect modelling. These results were compared to reliability estimated using different resolution of data using the Spearman-Brown formula. The measured reliability improved only marginally with increased monitoring length and levelled off after 5-6 days. Estimated reliability differed substantially when derived from different resolution of data: 3.9-5.4, 6.7-9.2, 13.4-26.7 and 26.3-87.7 days of monitoring was required to achieve an ICC = 0.80 using an hour-by-hour, a day-by-day, a week-by-week and a period-by-period approach, respectively. Reliability could not be correctly estimated from any single resolution of data. We conclude that reconsideration is needed with regard to how reproducibility of objectively measured PA is analysed and interpreted.Funding Information
- Western Norway University of Applied Sciences (na)
- County Municipality of Sogn og Fjordane (na)
This publication has 41 references indexed in Scilit:
- Quality Control Methods in Accelerometer Data Processing: Defining Minimum Wear TimePLOS ONE, 2013
- ActiGraph and Actical Physical Activity MonitorsMedicine & Science in Sports & Exercise, 2012
- Best Practices for Using Physical Activity Monitors in Population-Based ResearchMedicine & Science in Sports & Exercise, 2012
- Comparison of Accelerometer Cut Points for Predicting Activity Intensity in YouthMedicine & Science in Sports & Exercise, 2011
- How many days of monitoring predict physical activity and sedentary behaviour in older adults?International Journal of Behavioral Nutrition and Physical Activity, 2011
- How Many Days Are Enough? A Study of 365 Days of Pedometer MonitoringResearch Quarterly for Exercise and Sport, 2009
- Calibration of two objective measures of physical activity for childrenJournal of Sports Sciences, 2008
- How Many Days Was That? We're Still Not Sure, But We're Asking the Question Better!Medicine & Science in Sports & Exercise, 2008
- Application of Generalizability Theory to Measurement of Activity in Males Who are Not Regularly Active: A Preliminary ReportResearch Quarterly for Exercise and Sport, 1998
- STATISTICAL METHODS FOR ASSESSING AGREEMENT BETWEEN TWO METHODS OF CLINICAL MEASUREMENTThe Lancet, 1986