Free-living validation and harmonization of 10 wearable step count monitors.
Document Type
Article
Publication Date
2021
Abstract
This study aimed 1) to determine the step count accuracy of numerous wrist-, hip-, and thigh-worn consumer and research monitors (and their corresponding algorithms) compared with the StepWatch (SW) across all waking hours under free-living conditions and 2) to develop correction methods to calibrate all monitors to the SW. Forty-eight participants 28 ± 12 yr old (mean ± SD) wore monitors across two waking days. Different wrist (Apple Watch Series 2, Fitbit Alta, Garmin vivofit 3, and ActiGraph GT9X), hip (Yamax Digiwalker SW-200, Omron HJ-325, GT9X, and Fitbit Zip), and thigh (activPAL) monitors were worn across 2 d, with the exception of the SW, which was worn on both days. Monitor estimates were compared with SW to compute percent of SW steps, absolute percent error, mean difference, root-mean-square error, and Pearson correlations. Monitor-specific correction factor linear regression models were fit to estimate SW steps and evaluated using leave-one-subject-out cross validation. All monitors were significantly different from the SW (P < 0.05). Consumer wrist and hip monitors underestimated SW steps (72%–91% of SW steps per day), whereas step estimates from research monitors ranged widely (67%–189%). Mean absolute percent error across all devices were greater than 10%. After a correction method was applied, all monitor estimates were not significantly different from SW steps. Overall, some consumer monitors produced step estimates that are closer to the validated SW than research-grade monitors (and their corresponding algorithms) and could be used to measure steps for healthy adults under free-living conditions. The specific correction methods may facilitate comparisons across studies and support research efforts using consumer and research monitors for large-scale population surveillance and epidemiological studies.
Publication Title
Translational Journal of the American College of Sports Medicine
Volume
6
Issue
4
Digital Object Identifier (DOI)
10.1249/TJX.0000000000000172
Citation Information
Toth, Lindsay; Park, S.; Marcotte, R. T.; Paulus, P.; Lauricella, L.; Kim, A. H.; Crouter, S. E.; Springer, C. M.; Staudenmayer, J. W.; and Bassett, D. R., "Free-living validation and harmonization of 10 wearable step count monitors." (2021). UNF Faculty Research and Scholarship. 3250.
https://digitalcommons.unf.edu/unf_faculty_publications/3250
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