Research Database

188 results for "Validation"

Isolating out-of-bed wear from non-wear and in-bed wear periods in young adults hip-worn accelerometer data (continuous wear protocol)

  • Presented on 2015

Background: The published literature shows no automated method valid for isolating adults out-of-bed wear in continuously worn (24h/day) accelerometer data. We developed an automated algorithm (AA) for continuous hip-worn protocol Actigraph (GT3X+) data that separates out-of-bed wear from in-bed wear and non-wear periods. Methods: In 95 participants of the ...


Comparing objective measures of activity in the women health initiative study

  • Presented on 2015

Purpose: The study aims were: 1) to propose an improved version of Activity Intensity (AI) to summarize raw tri-axial accelerometry data; 2) to compare AI and Activity Count (AC) with regard to distinguishing between different activities and predicting energy expenditure. Methods: 200 postmenopausal women performed 9 lifestyle activities in the laboratory, each wearing an ...



Evaluation of reliability and validity of the General Practice Physical Activity Questionnaire (GPPAQ) in 60–74 year old primary care patients

  • Published on Sept. 2, 2015

Background: GPPAQ (General Practice Physical Activity Questionnaire) is a self-assessment physical activity questionnaire widely used in primary care. Reliability and validity data in older people are lacking. The study aims were: to assess GPPAQ’s reliability and validity in 60–74 year olds from the PACE-Lift (Pedometer Accelerometer Consultation Evaluation-Lift) physical activity ...


Reliable assessment of physical activity in disease: an update on activity monitors

  • Published on Sept. 2014

Purpose of Review: Physical activity is the main determinant of variability of individual energy expenditure. Reliable assessment of the activity level of an individual provides information on energy requirement and vital health. Here, evidence is presented on the validity of methods to assess physical activity as applied in health and ...


Validity of the Global Physical Activity Questionnaire (GPAQ) in assessing levels and change in moderate-vigorous physical activity and sedentary behaviour

  • Published on Dec. 10, 2014

Background: easible, cost-effective instruments are required for the surveillance of moderate-to-vigorous physical activity (MVPA) and sedentary behaviour (SB) and to assess the effects of interventions. However, the evidence base for the validity and reliability of the World Health Organisation-endorsed Global Physical Activity Questionnaire (GPAQ) is limited. We aimed to assess ...


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 ...