Research Database

Validity of three accelerometers to investigate lying, sitting, standing and walking

  • Published on May 23, 2019

Background: Hospital stays are associated with high levels of sedentary behavior and physical inactivity. To objectively investigate physical behavior of hospitalized patients, these is a need for valid measurement instruments. The aim of this study was to assess the criterion validity of three accelerometers to measure lying, sitting, standing and ...


Measuring Time in the Office Using Bluetooth Sensors: Feasibility and Validity Considerations

  • Published on Mar, 2019

The office is a key setting for intervening to reduce sitting, therefore office-specific activity measures are needed to evaluate interventions. We tested whether valid measures of office time and office-specific activities could be obtained using Bluetooth sensing with a variety of sampling intervals, receiver wear positions, and beacon placements. Workers ...


Actigraphy-based sleep estimation in adolescents and adults: a comparison with polysomnography using two scoring algorithms

  • Published on Jan 18, 2018

Objectives: Actigraphy is widely used to estimate sleep-wake time, despite limited information regarding the comparability of different devices and algorithms. We compared estimates of sleep-wake times determined by two wrist actigraphs (GT3X+ versus Actiwatch Spectrum [AWS]) to in-home polysomnography (PSG), using two algorithms (Sadeh and Cole-Kripke) for the GT3...


Correlates of accelerometer-assessed physical activity and sedentary time among adults with type 2 diabetes

  • Published on Nov 9, 2017

Objectives: The aims of this study were to describe the volume and patterns of objectively assessed sedentary behavior, light intensity physical activity (LPA) and moderate-vigorous physical activity (MVPA), and to examine socio-demographic correlates, among adults living with type 2 diabetes. Methods: Participants (n = 166) wore an accelerometer (Actigraph® GT3X+) for seven ...


Effect of ActiGraph’s low frequency extension for estimating steps and physical activity intensity

  • Published on Nov 20, 2017

Abstract: This study examined the effects of the ActiGraph's (AG) low-frequency extension (LFE) filter on steps and physical activity classification in the free-living environment. Thirty-four African-American women (age, 24.5±5.2 years; BMI, 24.9±4.5 kg/m2) had daily activity measured simultaneously with an AG-GT3X+ accelerometer and a New Lifestyles NL-800 pedometer for seven ...



Using Bluetooth proximity sensing to determine where office workers spend time at work

  • Published on Mar 7, 2018

Background: Most wearable devices that measure movement in workplaces cannot determine the context in which people spend time. This study examined the accuracy of Bluetooth sensing (10-second intervals) via the ActiGraph GT9X Link monitor to determine location in an office setting, using two simple, bespoke algorithms. Methods: For one ...


Estimating Energy Expenditure with ActiGraph GT9X Inertial Measurement Unit.

  • Published on May 2018

Purpose: The purpose of this study was to explore whether gyroscope and magnetometer data from the ActiGraph GT9X improved accelerometer-based predictions of energy expenditure (EE). Methods: Thirty participants (mean ± SD: age, 23.0 ± 2.3 yr; body mass index, 25.2 ± 3.9 kg·m) volunteered to complete the study. Participants wore five GT9X monitors (right ...



Measurement of Active and Sedentary Behavior in Context of Large Epidemiologic Studies

  • Published on Feb 2018

Introduction/Purpose: To assess the utility of measurement methods that may be more accurate and precise than traditional questionnaire-based estimates of habitual physical activity and sedentary behavior we compared the measurement properties of a past year questionnaire (AARP) and more comprehensive measures: an internet-based 24-h recall (ACT24), and a variety ...