Establishing Raw Acceleration Thresholds to Classify Sedentary and Stationary Behaviour in Children

• Published in: Children (Basel) Vol. 5; no. 12; p. 172
• Main Authors: Hurter, Liezel, Fairclough, Stuart J, Knowles, Zoe R, Porcellato, Lorna A, Cooper-Ryan, Anna M, Boddy, Lynne M
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI 19.12.2018; MDPI AG
• Subjects: accelerometers; activity classification; cut points; wearable technology; cut points; accelerometers; wearable technology; activity classification
• ISSN: 2227-9067; 2227-9067
• DOI: 10.3390/children5120172

This study aimed to: (1) compare acceleration output between ActiGraph (AG) hip and wrist monitors and GENEActiv (GA) wrist monitors; (2) identify raw acceleration sedentary and stationary thresholds for the two brands and placements; and (3) validate the thresholds during a free-living period. Twenty-seven from 9- to 10-year-old children wore AG accelerometers on the right hip, dominant- and non-dominant wrists, GA accelerometers on both wrists, and an activPAL on the thigh, while completing seven sedentary and light-intensity physical activities, followed by 10 minutes of school recess. In a subsequent study, 21 children wore AG and GA wrist monitors and activPAL for two days of free-living. The main effects of activity and brand and a significant activity × brand × placement interaction were observed (all < 0.0001). Output from the AG hip was lower than the AG wrist monitors (both < 0.0001). Receiver operating characteristic (ROC) curves established AG sedentary thresholds of 32.6 mg for the hip, 55.6 mg and 48.1 mg for dominant and non-dominant wrists respectively. GA wrist thresholds were 56.5 mg (dominant) and 51.6 mg (non-dominant). Similar thresholds were observed for stationary behaviours. The AG non-dominant threshold came closest to achieving equivalency with activPAL during free-living.