Research Database

89 results for "Activity and Technology"

Using Bluetooth proximity sensing to determine location in a workplace

  • Published on Jun 21, 2017

Most wearable devices that measure sedentary and active time in workplaces cannot determine the context of that time. The ActiGraph wGT3X-BT and Link models allow users to not only measure movement but the wearer's location relative to a beacon using Bluetooth proximity detection. This function has yet to be ...


Estimating energy expenditure during outdoor level walking using Global Positioning System or accelerometry in patients with peripheral artery disease

  • Published on Jun 21, 2017

Introduction. Estimating energy expenditure (EE) related to outdoor walking capacity in peripheral artery disease (PAD) patients could allow a better standardization of the assessment of their limitations during free-living outdoor walking. However, there is no data regarding the accuracy of ambulatory methods to perform such estimations. Our aim was to ...


Utility of ActiGraph wear sensor in assessing wear-time in 24-hour wrist measurement

  • Published on Jun 21, 2017

There are no standard procedures for identifying wake wear, sleep wear and non-wear time from the 24-h accelerometer recordings. Participant diaries increase participant burden and frequently have missing values. The Choi algorithm identifies 90-min consecutive zero counts as non-wear time, allowing for 2 minutes of non-zero counts, thus possibly ignoring short ...




Free-living dynamic skeletal loading estimation using tri-axial accelerometers

  • Added on July 14, 2017

Hip bone mineral density (BMD) is an important biomarker of fracture risk, but as a standalone measure it lacks information on modifiable causal factors. The relationship between hip BMD and physical activity (PA)-based skeletal loading estimates could provide a biomarker for prescribing PA changes in high risk patients. Ten ...


Multilevel functional methods for modeling actigraphy data and its application to predicting mortality in the US population

  • Published on Jun 21, 2017

We will present the results of analysis of physical activity data collected with accelerometers on 10000+ subjects in National Health and Nutrition Examination Survey (NHANES), a nationally representative sample of the US population. The data have been analyzed with recently developed multilevel functional data analysis approaches that focus on modeling variability ...


Validity and Reliability of Fitbit Flex for Step Count, Moderate to Vigorous Physical Activity and Activity Energy Expenditure

  • Published on Sep 2, 2016

Objectives: To examine the validity and reliability of the Fitbit Flex against direct observation for measuring steps in the laboratory and against the Actigraph for step counts in free-living conditions and for moderate-to-vigorous physical activity (MVPA) and activity energy expenditure (AEE) overall. Methods: Twenty-five adults (12 females, 13 males) wore a Fitbit ...


Household-level correlates of children’s physical activity levels in and across 12 countries

  • Published on Aug 25, 2016

Objective: Household factors (electronic media equipment, play equipment, physical activity in the home, and social support) have been associated with childhood moderate- to vigorous-intensity physical activity (MVPA), but little is known about how these factors differ across diverse countries. The objective was to explore household correlates of objective MVPA in ...


Estimating Physical Activity and Sedentary Behavior in a Free-Living Context: A Pragmatic Comparison of Consumer-Based Activity Trackers and ActiGraph Accelerometry

  • Published on Jul 9, 2016

Background: Activity trackers are increasingly popular with both consumers and researchers for monitoring activity and for promoting positive behavior change. However, there is a lack of research investigating the performance of these devices in free-living contexts, for which findings are likely to vary from studies conducted in well-controlled laboratory settings. ...