Calibration of accelerometer output for children

Department of Exercise Science, University of Massachusetts, Amherst, MA 01003, USA.
Medicine &amp Science in Sports &amp Exercise (Impact Factor: 4.46). 12/2005; 37(11 Suppl):S523-30. DOI: 10.1249/
Source: PubMed

ABSTRACT Understanding the determinants of physical activity behavior in children and youths is essential to the design and implementation of intervention studies to increase physical activity. Objective methods to assess physical activity behavior using various types of motion detectors have been recommended as an alternative to self-report for this population because they are not subject to many of the sources of error associated with children's recall required for self-report measures. This paper reviews the calibration of four different accelerometers used most frequently to assess physical activity and sedentary behavior in children. These accelerometers are the ActiGraph, Actical, Actiwatch, and the RT3 Triaxial Research Tracker. Studies are reviewed that describe the regression modeling approaches used to calibrate these devices using directly measured energy expenditure as the criterion. Point estimates of energy expenditure or count ranges corresponding to different activity intensities from several studies are presented. For a given accelerometer, the count cut points defining the boundaries for 3 and 6 METs vary substantially among the studies reviewed even though most studies include walking, running and free-living activities in the testing protocol. Alternative data processing using the raw acceleration signal is recommended as a possible alternative approach where the actual acceleration pattern is used to characterize activity behavior. Important considerations for defining best practices for accelerometer calibration in children and youths are presented.

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Available from: Kathleen F Janz, Oct 15, 2014
    • "Three hundred and ninety-six children met these criteria (valid days = 3.49 ± 0.52). Age specific cut-points were applied for MVPA as described by Freedson et al. (2005) and used in the National Health and Nutrition Examination Survey (NHANES) (Troiano et al., 2008). MVPA bouts, as described by Mark and Janssen (2009), were identified as sporadic sessions of activity (b 5 min); short bouts of activity (5–b10 min); and medium-to-long bouts of activity (≥10 min) were considered. "
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    ABSTRACT: Accumulating moderate-to-vigorous physical activity (MVPA) in bouts of 10 min is associated with improved cardio-metabolic risk factors (CMRF) in adults.
    Preventive Medicine 01/2015; 73. DOI:10.1016/j.ypmed.2015.01.022 · 2.93 Impact Factor
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    • "Children were included in the study if they accumulated at least two weekdays and one weekend day with at least 10 h of wearing time. Age-dependant cut-offs (Freedson et al. 2005) were used to define moderate-tovigorous physical activity (MVPA), while SB was defined as an intensity of less than 100 counts per minute (cpm) (Trost et al. 2011). "
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    ABSTRACT: We evaluated whether regional differences in physical activity (PA) and sedentary behaviour (SB) existed along language boundaries within Switzerland and whether potential differences would be explained by socio-demographics or environmental characteristics. We combined data of 611 children aged 4 to 7 years from four regional studies. PA and SB were assessed by accelerometers. Information about the socio-demographic background was obtained by questionnaires. Objective neighbourhood attributes could be linked to home addresses. Multivariate regression models were used to test associations between PA and SB and socio-demographic characteristics and neighbourhood attributes. Children from the German compared to the French-speaking region were more physically active and less sedentary (by 10-15 %, p < 0.01). Although German-speaking children lived in a more favourable environment and a higher socioeconomic neighbourhood (differences p < 0.001), these characteristics did not explain the differences in PA behaviour between French and German speaking. Factors related to the language region, which might be culturally rooted were among the strongest correlates of PA and SB among Swiss children, independent of individual, social and environmental factors.
    International Journal of Public Health 01/2015; 60(3). DOI:10.1007/s00038-014-0645-8 · 1.97 Impact Factor
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    • "Adolescents were instructed to wear the accelerometer for 7 consecutives days at the lower back fitted with an elastic belt, excepted during sleep hours and water-based activities. The Freedson's age-specific cut-points were used to estimate intensities of total PA, moderate PA and vigorous PA (Freedson et al., 2005). Variables obtained by the ActiGraph accelerometer were analyzed as counts per minute (cpm) for total PA and min/day for levels of PA. "
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