Classification du comportement sédentaire et des activités physiques en utilisant les points de rupture de l'accéléromètre chez les enfants âgés entre 9 et 11 ans

Objectives: To validate accelerometer counts against oxygen uptake in 9 to 11 years old children performing a number of highly variable physical activities and to determine accelerometer cut-off points for sedentary behavior, light, moderate, and vigorous physical activities. Equipment and methods: Eight boys and 6 girls aged 9 to 11 years old (height: 1.40 ± 0.06 m, body mass: 33.5 ± 5.1 kg, BMI: 16.9 ± 2.0 kg/m ² , body fat: 17.0 ± 4.8%, estimated VO ₂ max: 50.85 ± 4.8 ml.kg ⁻¹ .min ⁻¹ ) volunteered to participate in this study. They performed eight activities of different intensity namely watching TV, arts-crafts, slow and brisk forward walking, slow backward walking, forward running, aerobics and step-ups while VO ₂ and counts were determined using indirect calorimetry and accelerometer, respectively. Results: A highly significant correlation was found between accelerometer counts and VO ₂ (r = 0.86, P < 0.01). Significant differences were observed between predicted and measured VO2 for ART, SWB and Aerobic activities (P = 0.0003; P < 0.0001 and P = 0.0004, respectively). Bland and Altman plot revealed no significant bias for all other activities (−0.6 ml.kg ⁻¹ .min ⁻¹ , P = 0.347) with 95% limits of agreement (LoA) ± 9.7 ml.kg ⁻¹ .min ⁻¹ . In addition, watching TV and participating in art activities were classified as sedentary activities (< 61 counts. min ⁻¹ ), slow walking forward was classified as light activity (61–3435 counts. min ⁻¹ ), slow backward walking, brisk walking and aerobics were classified as moderate activities (3436–6100 counts. min ⁻¹ ) and step-ups and running were defined as vigorous activities (≥ 6101 counts. min ⁻¹ ).