Description

In this paper, energy expenditure regression models and physical activity intensity cut-points were developed for the raw acceleration metric Euclidean norm minus one (ENMO) in both adults and children using GENEActiv and ActiGraph accelerometers worn at the right hip or non-dominant wrist. The provided code simply calculates ENMO at a user-specified epoch. For further processing, authors also direct readers to the GGIR package, for which there are copious resources available.

Development/Validation

Sample: 60 (29 males) healthy children and adults 7-65 years of age

Setting: Laboratory

Activities: Activities of daily living, stationary behaviors, stepping, and treadmill walking and runing

Criterion: Ergospirometry system (VO₂)

Accelerometer(s): ActiGraph GT3X+ or GENEActiv on right hip or non-dominant wrist

Validation approach: Cross-validation

Phase Designation

(What's this?)

This model is in Phase 1.

Instructions

The R code defines a function to calculate ENMO. Users specify the sampling rate/frequency, where to save output files, the desired epoch over which to calculate ENMO, and the filepath where the csv files are stored. These csv files should be either ActiGraph raw data (with timestamps and the 10 rows of header information) or a GENEActiv file. There is an example ActiGraph data sheet, but a GENEActiv data sheet is not currently available. Further instructions are in the R code. More information about R is found here.

This code relies on R software which can be downloaded for free at https://www.r-project.org/

Attached Files

Download all files as a .zip or download individual files below.

Code

Example ActiGraph data

Example GENEActiv data (coming soon!)

Note: Compared to the original source, code was edited for consistency, example data was added, functions were unchanged

Source Information

Reference:

Hildebrand, M. Van Hees, V.T., Hansen, B. H., & Ekelund, U. L. F. (2014). Age group comparability of raw accelerometer output from wrist-and hip-worn monitors. Medicine and Science in Sports and Exercise, 46(9), 1816-1824. http://doi.org/10.1249/MSS.0000000000000289 Link to paper

Original source for code:

http://links.lww.com/MSS/A367

Corresponding author: Ulf Ekelund, ulf.ekelund@nih.no

Contact

Kimberly Clevenger at accelerometerrepository@gmail.com