title: Discrepancies in accelerometer-measured physical activity in children due to cut-point non-equivalence and placement site.
abstract: This study examined dissonance in physical activity (PA) between two youth-specific hip-derived intensity cut-points for the Actiwatch (AW), and compared PA between hip and wrist placements using site-specific cut-points. Twenty-four children aged 11.2 ± 0.5 years wore the AW on the right hip and non-dominant wrist during a typical school day. Minutes of sedentary behaviour and vigorous activity were greater using Puyau et al. (2002) cut-points, but light, moderate, and moderate-to-vigorous (MVPA) were greater when derived using Puyau et al. (2004) cut-points (P < 0.01). Total hip activity counts were lower than wrist. Sedentary minutes were greater at the hip, but minutes of light, vigorous and MVPA were lower (P < 0.01). Moderate minutes were greater at the hip, but differed only when applying the Puyau et al. (2004) cut-points (P < 0.01). In conclusion, data comparisons between two hip derived AW cut-points and between hip and wrist data are inappropriate. Future researchers using the AW at the hip should present data reduced using both published cut-points. As hip and wrist data differ, the wrist placement is preferable as it will likely increase children's compliance to monitoring protocols due to reduced obtrusiveness compared to the hip.
authors.affiliation: School of Education, Durham University, Leazes Road, Durham DH1 1TA, United Kingdom. ash.routen@durham.ac.uk
authors.forename: Ash C
authors.initials: AC
authors.lastname: Routen
authors.forename: Dominic
authors.initials: D
authors.lastname: Upton
authors.forename: Martin G
authors.initials: MG
authors.lastname: Edwards
authors.forename: Derek M
authors.initials: DM
authors.lastname: Peters
mesh_terms: D056044:Actigraphy / Q000379:methods*; D002648:Child; D015444:Exercise; D005260:Female; D006615:Hip; D006801:Humans; D008297:Male; D005082:Physical Exertion; D012016:Reference Values; D015203:Reproducibility of Results; D012146:Rest; D057185:Sedentary Behavior; D014953:Wrist