ORCID
- Zhou, Shang-Ming: 0000-0002-0719-9353
Abstract
ObjectiveTo classify wear and non-wear time of accelerometer data for accurately quantifying physical activity in public health or population level research.DesignA bi-moving-window-based approach was used to combine acceleration and skin temperature data to identify wear and non-wear time events in triaxial accelerometer data that monitor physical activity.SettingLocal residents in Swansea, Wales, UK.Participants50 participants aged under 16 years (n=23) and over 17 years (n=27) were recruited in two phases: phase 1: design of the wear/non-wear algorithm (n=20) and phase 2: validation of the algorithm (n=30).MethodsParticipants wore a triaxial accelerometer (GeneActiv) against the skin surface on the wrist (adults) or ankle (children). Participants kept a diary to record the timings of wear and non-wear and were asked to ensure that events of wear/non-wear last for a minimum of 15 min.ResultsThe overall sensitivity of the proposed method was 0.94 (95% CI 0.90 to 0.98) and specificity 0.91 (95% CI 0.88 to 0.94). It performed equally well for children compared with adults, and females compared with males. Using surface skin temperature data in combination with acceleration data significantly improved the classification of wear/non-wear time when compared with methods that used acceleration data only (p<0.01).ConclusionsUsing either accelerometer seismic information or temperature information alone is prone to considerable error. Combining both sources of data can give accurate estimates of non-wear periods thus giving better classification of sedentary behaviour. This method can be used in population studies of physical activity in free-living environments.
DOI
10.1136/bmjopen-2014-007447
Publication Date
2015-05-01
Publication Title
BMJ Open
Volume
5
Issue
5
ISSN
2044-6055
Organisational Unit
School of Nursing and Midwifery
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License
First Page
e007447
Last Page
e007447
Recommended Citation
Zhou, S. M., Hill, R., Morgan, K., Stratton, G., Gravenor, M., Bijlsma, G., & Brophy, S. (2015) 'Classification of accelerometer wear and non-wear events in seconds for monitoring free-living physical activity', BMJ Open, 5(5), pp. e007447-e007447. Available at: https://doi.org/10.1136/bmjopen-2014-007447
