Impact of Resistance Training on Body Composition, Physical Fitness, and Cardiometabolic Health in Children and Adolescents With Overweight/Obesity: An Umbrella Review With Meta-Analyses

Background: Resistance training (RT) is increasingly recognized as a promising exercise modality for enhancing health and fitness in children and adolescents. However, evidence remains inconsistent in those with overweight/obesity. This umbrella review synthesized evidence from systematic reviews to evaluate RT effects on body composition, physical fitness, and cardiometabolic health in this population. Methods: We searched seven databases from inception to February 2026 for systematic reviews with meta-analyses comparing RT versus controls in children and adolescents with overweight/obesity. Main outcomes included percent body fat, fat-free/lean mass, muscular strength, cardiorespiratory fitness, and cardiometabolic markers. We conducted meta-analyses on unique primary data, with subgroup analyses by comparator type (active vs. inactive), training frequency (1–2 vs. ≥ 3 sessions/week), duration (≤ 12 vs. > 12 weeks), and age (≤ 12 vs. > 12 years). Results: Sixteen systematic reviews (67 primary studies, 5112 participants) were included. Compared with all non-RT control conditions, RT decreased percent body fat (mean difference [MD]: −0.53%; 95% confidence interval [CI]: −1.00 to −0.06) and increased fat-free/lean mass (MD: 0.48 kg; 95% CI: 0.23 to 0.74). Muscular strength also improved significantly, with consistent benefits across body regions, training frequencies, durations, and age groups. Subgroup analyses indicated significant improvements in cardiorespiratory fitness, visceral fat, and fasting insulin versus inactive controls. Conclusion: This umbrella review demonstrates that RT significantly improves body composition and physical fitness in children and adolescents with overweight/obesity, alongside modest cardiometabolic health benefits. Our findings support integrating RT into school- and community-based programs for pediatric obesity management.