title: Moderate and vigorous physical activity intensity cut-points for the Actical accelerometer.
abstract: Accelerometry is increasingly used as a physical activity surveillance device that can quantify the amount of time spent moving at a range of intensities. This study proposes physical activity intensity cut-points for the Actical accelerometer. Thirty-eight volunteers completed a multi-stage treadmill protocol at 3, 5, and 8 km · h⁻¹ (2, 3.3, and 8 METs) while wearing Actical accelerometers initialized to collect data in 60-s epochs. Using a decision boundary analytical approach, moderate and vigorous physical activity intensity cut-points were derived for the Actical accelerometer. In adults (n = 26), the cut-point for moderate physical activity intensity occurred at 1535 counts per minute and the vigorous cut-point occurred at 3960 counts per minute. In children (n = 12), the cut-point for moderate physical activity intensity occurred at 1600 counts per minute and the vigorous cut-point occurred at 4760 counts per minute. Improved classification of physical activity intensity using the decision boundary cut-points was observed compared with using mean values for each protocol stage. The cut-points derived are recommended for use in adults. The cut-points derived for children confirm the findings of previous studies.
authors.affiliation: CHEO Research Institute, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada. rcolley@cheo.on.ca
authors.forename: Rachel C
authors.initials: RC
authors.lastname: Colley
authors.forename: Mark S
authors.initials: MS
authors.lastname: Tremblay
mesh_terms: D056044:Actigraphy / Q000295:instrumentation*; D000293:Adolescent; D000328:Adult; D000886:Anthropometry; D002170:Canada; D002648:Child; D005080:Exercise Test; D006801:Humans; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D005082:Physical Exertion / Q000502:physiology*; D011795:Surveys and Questionnaires; D055815:Young Adult