Validity of the Actical for estimating free-living physical activity
Crouter, 2011
Description
A 2-regression method is presented in which the counts/15-s and coefficient of variation of hip-worn Actical counts/15-s are used to determine METs. This approach was developed in adults performing structured activities over a range of intensities and cross-validated in an independent sample of adults in free-living. Bias was 8.78 (sedentary), 0.8 (light), and -9.6 (moderate-to-vigorous) minutes over the six-hour free-living observation period.
Development/Validation
Sample: 48 (24 males) healthy adults, 35.0±11.4 years of age
Setting: Laboratory, university, or home
Activities: Activities of daily living, overground walking and running, sports, stairs, stationary
Criterion: Cosmed K4b2 (VO2)
Accelerometer(s): Actical on left hip
Validation approach: Independent sample cross-validation with 29 participants (12 males, 20-55 years of age) in free-living
Instructions
The coefficient of variation (CV) for each 15-second epoch and all possible combinations of the surrounding three 15-sec epochs is calculated. So, the CV is calculated for the 15-s epoch of interest and (1) the three preceding 15-s epochs, (2) the two preceding 15-s epochs and one 15-s epoch that followed, (3) the one preceding 15-s epoch before and the two 15-s that followed, and (4) the three 15-s epochs that followed. Then, the lowest CV for each 15-second epoch is used to determine the appropriate equation for predicting METs/min.
Source Information
Reference:
Crouter, S. E., DellaValle, D. M., Horton, M., Haas, J. D., Frongillo, E. A., & Bassett, D. R. (2011). Validity of the Actical for estimating free-living physical activity. European Journal of Applied Physiology, 111(7), 1381-1389. https://doi.org/10.1007/s00421-010-1758-2 Link to Paper
Corresponding author: Scott Crouter, Scott.crouter@umb.edu
Contact
Kimberly Clevenger at accelerometerrepository@gmail.com