Relationships between accelerometer-assessed physical activity and health in children: impact of the activity-intensity classification method

It is unknown whether relationships detected between physicalactivity intensity and health differ according to accelerometerthresholds used [sample-specific thresholds (ssts), publishedthresholds (pts) or the individualized activity-related timeequivalent (arteacc)]. ssts were developed through acti-graph calibration in 52 boys, aged 8-10 years. the boys subsequentlywore an actigraph for seven days. ssts, pts andarteacc for moderate (mpa) and vigorous (vpa) activitywere applied. waist circumference (wc), peak oxygen consumption(vo2peak) and blood pressure were assessed. afterapplying ssts, 48.9% of boys achieved 60+ minutes of dailymvpa, compared with 8.5% with pts and 100% witharteacc. mpa and vpa were correlated with wc andvo2peak, regardless of whether pts or ssts were used (wc:mpa r = -0.37 to -0.43; vo2peak: r = 0.34 to 0.39, p < 0.05).with arteacc, only vpa was correlated with wc (r = -0.39, p< 0.01) and vo2peak (r = 0.35, p < 0.05). relationships withblood pressure were statistically non-significant. althoughestimates of the quantity of activity differed according to thresholdsused, relationships detected with health were consistentregardless of whether ssts or pts were employed. there wasno advantage of using ssts or individualized thresholds. researchersare encouraged to use pts to ensure greater comparabilitybetween studies.