Author Interviews, BMJ, Exercise - Fitness, Technology / 13.05.2015
Combining Acceleration and Skin Temperature Can Improve Accuracy of Physical Activity Monitors
MedicalResearch.com Interview with:
Dr. Shang-Ming Zhou
Senior Lecturer in Statistical Modelling and Analytics for Epidemiology and Public Health,
Public Health Informatics Group,
Health Information Research Unit (HIRU),
UKCRC DECIPHer (Development and Evaluation of Complex Interventions for Public Health Improvement) Centre,
College of Medicine, Swansea University, Swansea, UK
Medical Research: What is the background for this study? What are the main findings?
Response: In medical and sport science research, body-worn accelerometers are widely used to provide objective measurements of physical activity. However, accelerometers collect data continuously even during periods of nonwear (i.e. periods when participants may not be wearing their monitor, such as during sleeping). It is important to distinguish time of sedentary behaviours (eg. watching television) from time of nonwear. The clinical consequence of misclassification of accelerometer wear and nonwear would overestimate or underestimate physical activity level, and mislead the interpretation of the relationship between physical activity and health outcomes. Automated estimation of accelerometer wear and nonwear time events is particularly desired by large cohort studies, but algorithms for this purpose are not yet standardized and their accuracy needs to be established. This study presents a robust method of classifying wear and nonwear time events under free living conditions for triaxial accelerometers which combines acceleration and surface skin temperature data.
The new findings are: Either acceleration data or skin temperature data alone is inadequate to accurately predict wear and nonwear events in some scenarios under a free living condition; This study provides a simple and efficient algorithm on use of short time periods of consecutive data blocks for accurately predicting triaxial accelerometer wear and nonwear events; Combining both types of acceleration and skin temperature data can significantly improve the accuracy of accelerometer wear and nonwear events classification in monitoring physical activity. (more…)