Research Database

192 results for "Validation"

Classification of physical activity intensities using a wrist-worn accelerometer in 8–12-year-old children

  • Published on April 20, 2015

Background: Population-specific accelerometer cut-points are required to accurately determine the accumulation of physical activity of various intensities. Objectives: A calibration study was conducted (i) to determine the cut-points for the ActiGraph GT3X+, non-dominant, wrist-mounted accelerometer in children aged 8–12 years and (ii) to compare classification accuracies among the accelerometer's three ...


Methods to estimate aspects of physical activity and sedentary behavior from high frequency wrist accelerometer measurements

  • Published on June 25, 2015

Abstract: This investigation developed models to estimate aspects of physical activity and sedentary behavior from three-axis high frequency wrist worn accelerometer data. The models were developed and tested on twenty participants (n=10 males, n=10 females, mean age= 24.1, mean BMI = 23.9) who wore an Actigraph GT3X+ accelerometer on their dominant wrist ...


Impact of accelerometer data processing decisions on the sample size, wear time and physical activity level of a large cohort study

  • Published on Nov. 24, 2014

Background: Accelerometers objectively assess physical activity (PA) and are currently used in several large-scale epidemiological studies, but there is no consensus for processing the data. This study compared the impact of wear-time assessment methods and using either vertical (V)-axis or vector magnitude (VM) cut-points on accelerometer output. Methods: Participants (7,650 ...


Subjective and objective levels of physical activity and their association with cardiorespiratory fitness in rheumatoid arthritis patients

  • Published on March 13, 2015

Introduction: The aims of the present study were: (a) to examine the agreement between subjective (assessed via the International Physical Activity Questionnaire; IPAQ) and objective (accelerometry; GT3X) physical activity (PA) levels in patients with rheumatoid arthritis (RA), and (b) to evaluate the associations of RA patients’ subjective and objective ...



Separating Bedtime Rest from Activity Using Waist or Wrist-Worn Accelerometers in Youth

  • Published on April 11, 2014

Abstract: Recent interest in sedentary behavior and technological advances expanded use of watch-size accelerometers for continuous monitoring of physical activity (PA) over extended periods (e.g., 24 h/day for 1 week) in studies conducted in natural living environment. This approach necessitates the development of new methods separating bedtime rest and activity ...


Assessing sleep using hip and wrist actigraphy

  • Published on Jan. 19, 2015

Abstract: Wrist actigraphy is commonly used to measure sleep, and hip actigraphy is commonly used to measure activity. It is unclear whether hip-based actigraphy can be used to measure sleep. This study assessed the validity of wrist actigraphy and hip actigraphy compared to polysomnography (PSG) for the measurement of sleep. 108 ...


Reliability and Validity of the Transport and Physical Activity Questionnaire (TPAQ) for Assessing Physical Activity Behaviour

  • Published on Sept. 12, 2014

Background: No current validated survey instrument allows a comprehensive assessment of both physical activity and travel behaviours for use in interdisciplinary research on walking and cycling. This study reports on the test-retest reliability and validity of physical activity measures in the transport and physical activity questionnaire (TPAQ). Methods: The TPAQ ...


Machine Learning for Activity Recognition: Hip versus Wrist Data

  • Presented on June 18, 2013

Introduction: Wrist-worn accelerometers are convenient to wear and are associated with greater compliance. However, validated algorithms for predicting activity type and/or energy expenditure from wrist-worn accelerometer data are lacking. Purpose: To compare the activity recognition rates of an activity classifier trained on raw tri-axial acceleration signal (30 Hz) collected on ...


Ability of Thigh-Worn Actigraph and activPAL Monitors to Classify Posture and Motion

  • Published on Sept. 8, 2014

Purpose: This study compared sitting, standing, and stepping classifications from thigh-worn Actigraph and activPAL monitors under laboratory and free-living conditions. Methods: Adults wore both monitors on the right thigh while performing six sitting, two standing, nine stepping, one cycling activity, and writing on a whiteboard with intermittent stepping under laboratory ...