Impact of the choice of threshold on physical activity patterns in free living conditions among adolescents measured using a uniaxial accelerometer: The HELENA study |
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| Authors: | Jeremy Vanhelst Laurent Béghin Julia Salleron Jonathan R Ruiz Francesco B Ortega Charlene Ottevaere |
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| Institution: | 1. Inserm U995, IFR114, Faculty of Medicine, University Lille 2, Lille, France;2. CIC-PT-9301-Inserm-CH&3. U, University Hospital, Lille, Francejeremy.vanhelst@hotmail.fr;5. U, University Hospital, Lille, France;6. Department of Biostatistic, CH&7. U Lille, University Lille Nord de France, Lille, France;8. Unit for Preventive Nutrition, Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden;9. Department of Medical Physiology, School of Medicine, Granada University, Granada, Spain;10. Department of Public Health, Ghent University, Ghent, Belgium |
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| Abstract: | AbstractThe aim of this study was to assess the impact of the choice of threshold on physical activity patterns measured in adolescents under free living conditions (FLC) using a uniaxial accelerometer. The study comprised 2043 adolescents (12.5–17.5 years) participating in the HELENA Study. Participants wore a uniaxial accelerometer for 7 days. The PA patterns were assessed using thresholds determined from six different studies. For each of the thresholds used, the number of adolescents fulfilling the recommendation of 60 min of moderate to vigorous PA (MVPA) per day was also calculated. A significant difference was found between thresholds regardless of the activity level: differences of 38%, 207%, 136%, and 2780% for sedentary, light, moderate, and vigorous intensity PA, respectively (P < 0.001). Time of MVPA varied between methods from 25.3 to 55.2 min · day–1. The number of adolescents fulfilling the recommendation varied from 5.9% to 37% according to the thresholds used. The kappa coefficient for concordance in the assessment of the number of adolescents achieving the PA recommendations was generally low. The definition of the threshold for PA intensity may considerably affect the PA patterns in FLC when assessed using a uniaxial accelerometer and the number of participants fulfilling the recommendations. |
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| Keywords: | accelerometry physical activity adolescents threshold assessment |
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