RESEARCH ARTICLE Physical Education: The Effect of Epoch Lengths on Children’s Physical Activity in a Structured Context

Background Despite a consensus emerging that affirms that shorter epochs should be used in youth to correctly register physical activity levels in free-living conditions, little is known about its ef-fect on children’s physical activity conducted in structured periods of time. This study ana-lyzed the effect that epoch length (1, 2, 3, 5, 10, 15, 30 and 60s) may have on different physical activity intensities in physical education lessons. Methods A sample of 1912 individual measures of physical education lessons were measured with a GT3X accelerometer. Data were collected from 1227 Swiss Elementary school students re-cruited in 17 elementary schools. PE lessons lasted from 45minutes to one and a half hours. Data, originally collected in 1-s epoch, were then reintegrated into 2s, – 3s – 5s – 10s – 15s – 30s –60s epochs. Results Longer epochs were associated with higher levels of light (F = 8197.6, p <.001), moderat