Effects of school-based concurrent training on body composition and cardiorespiratory fitness in obese children in a randomized controlled trial

Childhood obesity is a major global health concern and is associated with increased risks of cardiovascular and metabolic diseases. School-based exercise interventions that combine high-intensity interval training with other exercise modalities may be effective, but the optimal approach for obese children remains unclear. This single-blind randomized controlled trial included thirty obese children (body mass index [BMI] ≥ 95th percentile for age and sex, mean age 10.1 ± 0.7 years, 15 boys and 15 girls). Participants were randomly assigned to one of three groups: concurrent training with sprint interval and aerobic exercise (CT1, n = 10, 5 boys, 5 girls), concurrent training with sprint interval and strength exercise (CT2, n = 10, 5 boys, 5 girls), or a non-exercise control group (CON, n = 10, 5 boys, 5 girls). Both intervention groups completed two sessions per week for eight weeks, each consisting of 10 min of sprint interval training followed by either 10 min of aerobic exercise (CT1) or 10 min of strength training (CT2). Body composition and cardiorespiratory fitness (CRF) were measured at baseline and post-intervention. Both CT1 and CT2 groups showed significant reductions in BMI and fat mass, and significant improvements in maximal oxygen uptake (VO₂max) compared to the control group (all p < 0.05). The increase in VO₂max was greater in the CT2 group than in the CT1 group (6.1 vs. 3.1 mL/kg/min, p < 0.01). Visceral adipose tissue was significantly reduced in CT1, while waist circumference was significantly reduced in CT2. No significant differences were found between the intervention groups for these outcomes. No adverse events were reported. Eight weeks of school-based sprint interval concurrent training, combined with either aerobic or strength exercise, effectively improved body composition and cardiorespiratory fitness in obese children. These results support the inclusion of such exercise protocols in school programs for the prevention and management of childhood obesity.