title: Reliability of the RT3 accelerometer for measurement of physical activity in adolescents.
abstract: The aim of this study was to assess the reliability of the RT3 accelerometer under conditions of normal physical activity. Sixty healthy individuals (30 boys, 30 girls) aged 10-16 years wore two accelerometers while performing different structured physical activities. The accelerometers were synchronized and data were recorded every minute during nine 15-min sessions of physical activity that varied in intensity from sedentary (watching television, playing video games) to vigorous (running on a treadmill at different speeds). Intra-instrument coefficients of variation (CV) were assessed using the formula CV = standard deviation of the measure x 100/mean of the measure. The intra-instrument coefficient of variation was higher for sedentary (17%) and light activity (16.2%) than moderate (9.3%) and vigorous activity (6.6%). These results confirmed the poor reliability of the RT3 for activity of low magnitude and frequency that was demonstrated in studies using a shaker.
authors.affiliation: Laboratoire RELACS, Université du Littoral Côte d'Opale, Dunkerque. jeremy.vanhelst@hotmail.fr
authors.forename: Jeremy
authors.initials: J
authors.lastname: Vanhelst
authors.forename: Denis
authors.initials: D
authors.lastname: Theunynck
authors.forename: Frédéric
authors.initials: F
authors.lastname: Gottrand
authors.forename: Laurent
authors.initials: L
authors.lastname: Béghin
mesh_terms: D000293:Adolescent; D002648:Child; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D018670:Monitoring, Ambulatory / Q000295:instrumentation*; D009043:Motor Activity; D005082:Physical Exertion; D012016:Reference Values; D015203:Reproducibility of Results