Accelerometer data requirements for reliable estimation of habitual physical activity and sedentary time of children during the early years - a worked example following a stepped approach. Issue 20 (17th October 2016)

• Record Type: Journal Article
• Authors: Bingham, Daniel D.; Costa, Silvia; Clemes, Stacy A.; Routen, Ash C.; Moore, Helen J.; Barber, Sally E.
• Is Part Of: Journal of sports sciences. Volume 34:Issue 20(2016)
• Page Start: 2005
• Page End: 2010
• Publication Date: 2016-10-17
• Subjects: Acclererometry -- measurement -- reliability -- young children -- physical activity -- sedentary time; Sports -- Periodicals; Sports -- Physiological aspects -- Periodicals; Sports -- Psychological aspects -- Periodicals; 612.044
• DOI: 10.1080/02640414.2016.1149605
• Languages: English
• ISSNs: 0264-0414

Abstract

ABSTRACT: This study presents a worked example of a stepped process to reliably estimate the habitual physical activity and sedentary time of a sample of young children. A total of 299 children (2.9 ± 0.6 years) were recruited. Outcome variables were daily minutes of total physical activity, sedentary time, moderate to vigorous physical activity and proportional values of each variable. In total, 282 (94%) provided 3 h of accelerometer data on ≥1 day and were included in a 6-step process: Step-1: determine minimum wear-time; Step-2: process 7-day-data; Step-3: determine the inclusion of a weekend day; Step-4: examine day-to-day variability; Step-5: calculate single day intraclass correlation (ICC) (2, 1); Step-6: calculate number of days required to reach reliability. Following the process the results were, Step-1: 6 h was estimated as minimum wear-time of a standard day. Step-2: 98 (32%) children had ≥6 h wear on 7 days. Step-3: no differences were found between weekdays and weekend days ( P ≥ 0.05). Step-4: no differences were found between day-to-day variability ( P ≥ 0.05). Step-5: single day ICC's (2, 1) ranged from 0.48 (total physical activity and sedentary time) to 0.53 (proportion of moderate to vigorous physical activity). Step-6: to reach reliability (ICC = 0.7), 3 days were required for all outcomes. In conclusion following a 7 day wear protocol, ≥6 h on any 3 days was found to have acceptable reliability. The stepped-process offers researchers a method to derive sample-specific wear-time criterion.