Comparison of wrist-worn and hip-worn activity monitors under free living conditions

Abstract

Purpose: Current recommendations state that individuals engage in 150 min of moderate or 75 min of vigorous intensity physical activity (PA) each week. Commercial PA monitors are becoming popular for everyday use. The accuracy of these devices, however, is not well understood. We sought to examine the accuracy of two commercial devices, one wrist and one hip-worn, under free-living conditions.

Methods: Twenty-two subjects wore two commercially available devices and one ActiGraph (AG) for seven consecutive days under normal activity.

Results: Mean steps per day between all three devices differed significantly. No differences were found in moderate-to-vigorous intensity physical activity (MPVA). Daily energy expenditure (EE) also differed significantly between the AG and the commercial devices. Bland–Altman analysis found poor agreement between the AG and the commercial devices with regards to steps and EE, but good agreement in MVPA.

Conclusion: Results suggest that the commercial devices are less accurate in estimating steps and EE. These devices did show good agreement with regards to MVPA, suggesting that they may provide useful feedback for individuals seeking to achieve the current PA guidelines for MVPA. Improvements are needed with regards to steps and EE estimation.

Keywords:

• Energy expenditure
• physical activity
• accelerometers
• steps

Acknowledgements

The authors would also like to thank the individuals who volunteered to participate in this study. This work was supported by a grant from the James Madison University College of Health and Behavioural Studies Research and Teaching Grants Programme, and the James Madison University College of Health and Behavioural Studies Mini-Grant Programme. The results of the study are presented clearly, honestly, and without fabrication, falsification, or inappropriate data manipulation, and statement that results of the present study do not constitute endorsement by ACSM.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Funding

This work was supported by the James Madison University College of Health and Behavioral Studies.