Use of Accelerometers in a Large Field-Based Study of Children: Protocols, Design Issues, and Effects on Precision

• DOI: 10.1123/jpah.5.s1.s98
• Publication Date: 2016-08-10T12:41:49Z
• Authors: Calum Mattocks; Andy Ness; Sam Leary; Kate Tilling; Steven N. Blair; Julian Shield; Kevin Deere; Joanne Saunders; Joanne Kirkby; George Davey Smith; Jonathan Wells; Nicholas Wareham; John Reilly; Chris Riddoch
• Keywords: Longitudinal Study; Longitudinal field

Background: Objective methods can improve accuracy of physical activity measurement in field studies but uncertainties remain about their use. Methods: Children age 11 years from the Avon Longitudinal Study Parents and (ALSPAC), were asked to wear a uni-axial accelerometer (MTI Actigraph) for 7 days. Results: Of 7159 children who attended assessment, 5595 (78%) provided valid measures. The reliability coefficient 3 days recording was .7 power detect difference 0.07 SDs ( P ≤ .05) > 90%. Measures tended be higher on first day (17 counts/min; 95% CI, 10–24) if wore monitor fewer days, these differences small. measures different those did not, modest. Conclusion: incorporated into large longitudinal children.