Pediatric obesity is considered one of the most important public health problems worldwide due to its high prevalence and associated comorbidities. Physical exercise has been shown to have an important role in the treatment of obesity and associated cardiometabolic dysfunction. Small-sided soccer games (SSSG) have been explored as a promising way of increasing physical exercise due to its benefits on cardiometabolic health and high degree of enjoyment, which favors long-term adherence.

The objective of this research is to determine the effects of a 16-week high-intensity SSSG-based exercise intervention on cardiometabolic risk factors, physical fitness, adherence to 24-hour movement patterns, enjoyment and adherence to the intervention in adolescents with metabolic dysfunction and compare them to the effects of a traditional soccer intervention.

The investigators hypothesize that high-intensity SSSG are more effective in improving the obesity-related cardiometabolic risk profile in adolescents with cardiometabolic dysfunction compared to traditional soccer training.

A parallel 3-arm randomized controlled trial will be conducted in adolescents with overweight and metabolic dysfunction between 11 and 15 years of age. The inclusion criteria are: (i) age between 11-15 years at the time of intervention start; (ii) overweight or obesity (BMI> 85th percentile); (iii) Abdominal obesity ≥90th percentile as assessed by waist circumference or a waist-to-height ratio ≥ 0.5; (iv) willing to participate in the study regardless of possible group allocation; (v) informed consent given by participant and legal representatives. Exclusion criteria: (i) health condition not compatible with participation in physical exercise; (ii) history of recent musculoskeletal injury hindering exercise participation; (iii) concurrent participation in a structured weight loss or exercise program.

Those eligible to participate in the study will be randomly assigned to one of three groups: i) SSSG group, ii) traditional soccer play group (TSG), or, iii) non-exercise intervention control group (CG). Participants in both exercise intervention groups will undergo a 16-week intervention. The SSSG group will participate in a high-intensity small-sided soccer games training, while the TSG will undergo a technical and tactical skills training program and traditional soccer training. The CG participants will continue with regular school physical education classes without any additional intervention. Before and after the intervention, all participants will be assessed for cardiometabolic and hepatic biochemical markers, physical fitness, anthropometry and body composition, blood pressure, objective daily physical activity and sleep quality, and perceived enjoyment of participation in SSSG and TSG. The primary outcomes of the study will be waist circumference and cardiorespiratory fitness.

The study protocol was approved by the Ethics Committee of the Faculty of Sport of the University of Porto and by the Scientific Ethics Committee of the Adventist University of Chile.

Inclusion Criteria:

• Age between 11-15 years at the time of intervention start
• Overweight or obesity (BMI> 85th percentile)
• Abdominal obesity ≥90th percentile as assessed by waist circumference or a waist-to- height ratio ≥ 0.5
• Willing to participate in the study regardless of possible group allocation
• Informed consent given by participant and legal representatives

Exclusion Criteria:

• Health condition not compatible with participation in physical exercise
• History of recent musculoskeletal injury hindering exercise participation
• Concurrent participation in a structured weight loss or exercise program