Accelerometer Monitoring Duration for Reliable Estimates of Physical Activity, Sedentary Behavior, and Step Counts in Preschoolers

Abstract

This study aims to establish the reliability of accelerometer-based measurements for physical activity, sedentary behavior, and step counts in preschoolers and determine the optimal monitoring duration necessary for reliable data. The study analyzed data from 434 preschoolers (ages 3–5) who wore waist-worn ActiGraph wGT3X-BT accelerometers for 7 days as part of the Sunrise Study in Spain. Two-way mixed effects intraclass correlation coefficients were calculated for various combinations of daily wear time and number of valid days to assess reliability. The Spearman–Brown prophecy formula was applied to determine the required days to achieve reliability scores of 0.7, 0.8, and 0.9.