Dr. Rachel Colley and Dr. Mark Tremblay recently published a paper in the Journal of Sports Sciences reporting on laboratory-determined moderate and vigorous intensity physical activity cut-points derived from the Actical accelerometer. This paper is of significant importance because the Canadian Health Measures Survey conducted by Statistics Canada uses the Actical accelerometer for direct measurement of physical activity of Canadians and this new paper will allow for more precise interpretation of the data from this survey. The full citation information is provided below.
R.C. Colley, M.S. Tremblay. Moderate and vigorous physical activity intensity cut-points for the Actical accelerometer. Journal of Sports Sciences 29(8):783-789, 2011.
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.