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Evenson, Kelly R. & Terry, James W., Jr. (2009). Assessment of Differing Definitions of Accelerometer Nonwear Time. Research Quarterly for Exercise and Sport, 80(2), 355-362. PMCID: PMC3321743


Measuring physical activity with objective measures, such as accelerometers, is becoming more common with researchers, as evidenced through the increasing number of research articles using accelerometers (R Troiano, 2005). Accelerometers measure acceleration multiple times within a given frequency and summarize this as a count over a pre-specified time period or epoch. The resultant count represents acceleration over the epoch length. Accelerometers are advantageous because they eliminate language or literacy difficulties, recall bias, and social desirability bias present with self-report measures of physical activity.

Reference Type

Journal Article

Year Published


Journal Title

Research Quarterly for Exercise and Sport


Evenson, Kelly R.
Terry, James W., Jr.