摘要：Background: Several studies have reported significant improvements in cardiorespiratory fitness (CRF) in children with high-intensity exercise. However, most research protocols focus on cycling and running. These protocols are not applicable for practical purposes in children. Objective: This study aims to assess the effect of an 11-week intervention using games protocols of two different intensities (high-intensity games and moderate-intensity games) on CRF and anthropometric variables in children. Methods: The participants included 48 schoolchildren aged between 9 to 10 years (9.48 ± 0.5 years). Children were randomized into two groups: high-intensity games (HIG) or moderate-intensity games (MIG). HIG group used relays race and small-sided games; >75% of maximum heart rate (HRmax). MIG group used cooperative and dynamics continued games; 60% - 74% HRmax. Both groups had two sessions per week for 11 weeks during physical education classes (PE). Before and after the interventions, participants completed the CRF test (20-meter shuttle run test) and measurements of anthropometric variables were taken: Body mass index (BMI), Body mass index Z-Score (BMI z-score), Waist circumference (WC), Body fat percentage (BF%) and Sum of skinfolds. Results: A significant time × group interaction was observed for CRF (F = 4.879, P = 0.032; ES = 0.6), between HIG and MIG. There were no significant differences time interaction between treatment groups for BMI (F = 1.158, P = 0.288), BMI z-score (F = 2.911, P = 0.095), BF% (F = 0.270, P = 0.606) and Sum of skinfolds (F = 1.481, P = 0.230). Conclusions: This study demonstrates that an 11-week HIG program, applied during PE classes, is more effective than MIG in the improvement of the CRF in children.
