Calibration and Cross-validation of Accelerometry in Children and Adolescents with Cystic Fibrosis

Commonly used cut-points may misclassify physical activity (PA) in people with cystic fibrosis (CF). The aim of this study was to develop and cross-validate condition-specific children adolescents CF. Thirty-five CF (15 girls; 11.6 ± 2.8 years) 28 controls (16 12.2 2.7 years), had their energy expenditure triaxial acceleration measured during six daily activities varying intensities. Euclidean Norm Minus One (ENMO) Mean Amplitude Deviation (MAD) were extracted using both GENEActiv (both wrists) ActiGraph GT9X wrists right waist) accelerometers. ROC curves determine healthy CF-specific raw for sedentary time (SED), moderate (MPA) vigorous (VPA). PA generally lower compared ENMO (60.2–73.1 vs. 63.5–86.8 mg) MAD (58.9–85.2 75.9–93.7 mg). These substantial inter-cut-point differences support the need disease-specific cut-points.