Diagnostic Criteria and Value of Multiple-index Joint Diagnosis of Exercise Intensity in Obese Children and Adolescents

  Objective  To establish a multi-index method for the diagnosis of exercise intensity, and provide a methodological reference for accurately diagnosing exercise intensity of obese children and adolescents.

  Methods  160 obese children and adolescents aged 10~17 were randomly divided into training group (n=120) and validation group (n=40). The METs, %HRR and vector magnitudes (VM₃) were measured for all participants during free walking and running at 3~7 km/h. Logistic regression was used to establish the multi-index joint diagnosis model, and the ROC curve was conducted with the prediction probability values (P_3METs and P_6METs), and the cut-off point of intensity was determined by the maximum Youden index. The area under the ROC curve was evaluated for diagnostic value, accuracy and weighted Kappa values were tested for accuracy and consistency.

  Results  The 3METs multi-index joint diagnosis model was Logist(P_3METs)=10.666-9.760×10^-2×%HRR-1.035×10^-3×VM₃-0.290×Age, while the 6METs was Logist(P_6METs)=-15.34+0.127×%HRR+6.316×10^-4×VM₃+0.176×Age. The cut-off point of 3METs for P_3METswas 0.315, and the area under curve of ROC was 0.891.The cut-off point of 6METs for P_6METswas 0.248, and the area under curve of ROC was 0.956. The accuracy of multiple-index joint diagosis was 79.62%, and the weighted Kappa value was 0.686.

  Conclusion  Multiple-index joint diagnosis model can be used to diagnose the exercise intensity of obese children and adolescents, which has high diagnostic value.The diagnostic criteria of light-intensity was P_3METs>0.315, moderate-intensity P_3METs ≤ 0.315 and P_6METs < 0.248, and high-intensity P_6METs ≥ 0.248.