Mean amplitude deviation calculated from raw acceleration data: a novel method for classifying the intensity of adolescents’ physical activity irrespective of accelerometer brand
Aittasalo, 2015
Description
Cut-points for mean amplitude deviation (MAD) for Hookie and ActiGraph monitors worn at the hip developed from adolescents performing walking and running. Sensitivity (95.0-100%), specificity (98.6-100%), and misclassification (0.0-2.5%) are reported.
Development/Validation
Sample: 20 (10 males) healthy adolescents, 13-15 years of age
Setting: Laboratory and track
Activities: Overground/self-paced walking and running, stationary
Criterion: Activity type
Accelerometer(s): ActiGraph GT3X on left hip, Hookie AM13 on right hip
Validation approach: Comparison to activity type
Instructions
Calculate MAD (mg) as the mean distance of data points about the mean where n is the number of samples in the epoch, ri is the ith resultant sample within the epoch and r(bar) is the mean resultant value of the epoch (see formula to the right). This can also be done in R using a package like acc or GGIR. In this paper, they used an epoch of 5.1 s (Hookie) or 4.3 s (ActiGraph).
Each epoch can they be classified using the cut-points, which are provided separately for the ActiGraph and Hookie monitors.
Source Information
Reference:
Aittasalo, M., Vähä-Ypyä, H., Vasankari, T., Husu, P., Jussila, A. M., & Sievänen, H. (2015). Mean amplitude deviation calculated from raw acceleration data: a novel method for classifying the intensity of adolescents’ physical activity irrespective of accelerometer brand. BMC Sports Science, Medicine and Rehabilitation, 7(1), 1-7. https://doi.org/10.1186/s13102-015-0010-0 Link to paper
Corresponding author: Minna Aittasalo, minna.aittasalo@uta.fi
Contact
Kimberly Clevenger at accelerometerrepository@gmail.com