HALO researchers Dr. Rachel Colley, Alysha Harvey, Kimberly Grattan and Dr. Kristi Adamo authored a paper, “Impact of accelerometer epoch length on physical activity and sedentary behaviour outcomes for preschool-aged children,” that was recently published in Health Reports. Citation details and a summary of the paper are below.

Colley RC, Harvey A, Grattan KP, Adamo KB. Impact of accelerometer epoch length on physical activity and sedentary behaviour outcomes for preschool-aged children. Health Rep. 2014 Jan 15;25(1):3-9.

ABSTRACT: Background. The Canadian Health Measures Survey uses accelerometry to collect physical activity and sedentary behaviour data. Between cycles 2 and 3, a transition was made from 60-second to 15-second epochs in accelerometry data for children aged 3 to 5. This study examines the impact of epoch length on physical activity and sedentary behaviour outcomes. Data and Methods. Twenty-nine children aged 3 to 5 wore two accelerometers at the same time, one initialized to collect data in 60-second epochs, and the other, in 15-second epochs. Comparisons between epoch settings were made for several physical activity variables. Results. Compared with the 60-second epoch setting, the 15-second setting captured more moderate-to-vigorous physical activity (MVPA) and sedentary time, but fewer steps and less light and total physical activity. The correlation between epoch settings was high for all variables except steps. Interpretation. The epoch length used in accelerometer data collection affects physical activity and sedentary behaviour data for preschool-aged children.

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