Science of accelerometry-based physical activity assessment: from sensor basics to applications toepidemiology studies
Kong Y. Chen, PhD MSCINational Institutes of Health, Bethesda Maryland USA

Abstract:
Physical activity can have immediate and long-term health benefits in people of all ages, abilities, andbackgrounds. Objective assessments of physical activity started with mechanical pedometers and footcontact switches and developed into smart watches/phone apps with wearable body sensor networks oftoday. Accelerometers have widely been used in clinical measurements and sport sciences (gait,
postures, falls, and performances) and now are the predominant sensors-of-choice for free-living
physical activity, sedentary behavior, and sleep in small clinical trials and large epidemiological studies.
In the last two decades, the technology and application of wearable devices in physical activity research
have experienced tremendous growth and advances. To educate the users and developers of physicalactivity monitors to better harness their powers and benefits, this lecture intents to describe bothdesign and application insights from past to future sensor technologies:
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Sensor fundamentals of accelerometry-based activity monitor and history of the field
Data processing approaches ranging from “counts” to machine learning or other sophisticatedmethods
Activity, sedentary, and sleep detections
Current monitor options and how to choose them according to research designs
Wear locations and their pros and cons
Validity and potential research use of consumer-based wearable devices
Comparability of different activity monitors
Application of activity/sleep monitors to large-scale epidemiology studies
Future perspectives on the field of objective physical activity measurements

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