Use of a 2-regression model for estimating energy expenditure in children
Crouter, 2012
Description
Two 2-regression models to predict METs were developed for a hip-worn ActiGraph in children (one for vertical axis and one for vector magnitude counts/10-s). Mean bias was 0.06 METs for vector magnitude counts and 0.15 METs for vertical axis counts.
Development/Validation
Sample: 106 (55 males) healthy children, 8-15 years of age
Setting: Inside/outside
Activities: Activities of daily living, overground/self-paced walking and running, sports/exercise, stationary
Criterion: Cosmed K4b2 (VO2)
Accelerometer(s): ActiGraph GT3X on right hip
Validation approach: Holdout of 33 participants
Instructions
The models can be implemented as described below or using the TwoRegression R package.
There are separate formulas for either vertical axis counts/10-s or vector magnitude counts/10-s (square root of the sum of the squared counts in each axis). The coefficient of variation (CV) for each 10-second epoch and all possible combinations of the surrounding five 10-sec epochs is calculated. So, the CV is calculated for the 10-sec epoch of interest and the 1) five 10-sec epochs before, 2) four 10-sec epochs before and one 10-sec epoch after, 3) three 10-sec epochs before and two 10-sec epochs after, 4) two 10-sec epochs before and three 10-sec epochs after, 5) one 10-sec epoch before and four 10-sec epochs after, and 6) five 10-sec epochs that followed. Then, the lowest CV for each 10-second epoch is used to determine the appropriate equation for predicting METs/min.
Vertical axis counts
Vector magnitude counts
Source Information
Reference:
Crouter, S. E., Horton, M., & Bassett Jr, D. R. (2012). Use of a 2-regression model for estimating energy expenditure in children. Medicine and Science in Sports and Exercise, 44(6), 1177. https://doi.org/10.1249/MSS.0b013e3182447825 Link to Paper
Corresponding author: Scott Crouter, Scott.crouter@umb.edu
Contact
Kimberly Clevenger at accelerometerrepository@gmail.com