Title

Accelerometer wear-site detection: When one site does not suit all, all of the time

RIS ID

112069

Publication Details

Rowlands, A. V., Olds, T. S., Bakrania, K., Stanley, R. M., Parfitt, G., Eston, R. G., Yates, T. & Fraysse, F. (2017). Accelerometer wear-site detection: When one site does not suit all, all of the time. Journal of Science and Medicine in Sport, 20 (4), 368-372.

Abstract

Objectives: Choice of accelerometer wear-site may facilitate greater compliance in research studies. We aimed to test whether a simple method could automatically discriminate whether an accelerometer was worn on the hip or wrist from free-living data. Design: Cross-sectional. Methods: Twenty-two 10-12. y old children wore a GENEActiv at the wrist and at the hip for 7-days. The angle between the forearm and the total acceleration vector for the wrist-worn monitor and between the pelvis and the total acceleration vector for the hip-worn monitor (i.e. the angle between the Y-axis component of the acceleration and the total acceleration vector) was calculated for each 5. s epoch. The standard deviation of this angle (SDangle) was calculated over time for the wrist-worn and hip-worn monitor for windows of varying lengths. We hypothesised that the wrist angle would be more variable than the hip angle. Results: Wear site could be discriminated based on SDangle; the shorter the time window the lower the optimal threshold and Area under the Receiver-Operating-Characteristic curve (AUROC) for discrimination of wear-site (AUROC = 0.833 (1. min) - 0.952 (12. h)). Classification accuracy was good for windows of 8. min (sensitivity = 90%, specificity = 87%, AUROC = 0.92) and plateaued for windows of ¿60. min (sensitivity and specificity >90%, AUROC = 0.95-0.96). Conclusions: We have presented a robust, computationally simple method that detects whether an accelerometer is being worn on the hip or wrist from 8 to 60. min of data. This facilitates the use of wear-site specific algorithms to analyse accelerometer data.

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Link to publisher version (DOI)

http://dx.doi.org/10.1016/j.jsams.2016.04.013