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Soccer as a novel therapeutic approach to pediatric obesity. A randomized controlled trial and its effects on fitness, body composition, cardiometabolic and oxidative markers.Preschool Children.


The increasing prevalence of childhood obesity (1) is associated with an increase in cardiovascular and metabolic risk and comorbidities (2). Evidence suggests that cardiovascular and metabolic risk factors (CMRF) in youth may persist throughout life even in the presence of improved nutritional status (3,4) and may compromise quality of life as well as life expectancy (5). Abdominal obesity, high blood pressure, elevated triglycerides and glucose, and reduced levels of high-density lipoprotein are commonly clustered as the metabolic syndrome (MS)(6). Recent research suggested the existence of other biological markers associated with pro-inflammatory and pro-oxidant states which are expressed at earlier ages and have greater sensitivity (3,7). These novel cardiometabolic markers include ghrelin, adiponectin and its isoforms, leptin, resistin, high sensitivity C-reactive protein, tumor necrosis factor alpha, interleukin-6, lipoprotein particularly its oxidized high-density and thiobarbituric acid reactive substances as a byproduct of lipid peroxidation, and markers of oxidative stress. Although variably defined, prevalence of MS has increased recently and has reached 15-17% among Portuguese obese children (8,9). If risk factor aggregation, rather than traditional criteria for MS, is used, more than one-half of obese children have two or more risk factors (3). This approach suggests that classical markers may not be sufficiently sensitive at childhood and highlight a need to consider other markers of CMRF.



Physical activity (PA) is important in childhood obesity prevention and is also related to CMRF and a variety of behaviours. Programs of systematic PA have a positive influence on CMRF, body composition (BC) and psychological well-being (PWB) in obese children (10,11,12,13). The evidence is based upon samples of variable size and age, and programs of PA of variable intensity, duration and type of activities (primarily individual in contrast to team sport activities). Nevertheless, all authors consistently affirm a need for future research centred on novel biological markers. Soccer has also been recommended as an effective “tool” for reducing CMRF in adults (14). Recent studies analysed the efficacy of a recreational soccer program on the health and physical fitness (PF) of overweight children (15,16). While CMRF were not assessed, the data suggested that soccer had a strong positive effect on weight control. Given this novelty, soccer interventions may also function as highly effective “medicine” for CMRF prevention in obese children. Of relevance, soccer is the most popular and practiced team sport for children worldwide.



The present study is an innovative effort to apply a recreational soccer intervention program for the prevention CMRF and for the improvement of BC, PF and PWB in obese children. Three main hypotheses will be tested: (1) systematic practice of recreational soccer has a moderate-to-high effect in reducing CMRF and body fat, and in improving PF and PWB; (2) systematic practice of recreational soccer has a greater effect than other individual sports in increasing energy expenditure, reducing CMRF, and improving PF and PWB; (3) with recreational soccer as the template for reducing the expression of CMRF, new subsets of markers with greater predictive and clinical utility will be developed.


A 6-month randomized controlled trial of two sports programs in obese children will be implemented. One hundred and twenty obese children will be recruited in the Pediatric Unit of the CUF Hospital, Porto. To be eligible for participation, children will be 10–12 years of age and will have a BMI greater than the CDC 95thpercentile (17). After baseline evaluation, children will be randomly assigned to two training groups (soccer, n=40; individual sport, n=40) and one control group (n=40). One group will undertake a soccer-training program (technical exercises and small-sided games), while the other group will undertake an individually-oriented activity program (walking, jogging). Training sessions will be performed for 3 times week, for 60min with an average HR >75%max in each session. CMRF, BC, PF and PWB will be assessed using recommended instruments and protocols. The control group comprises children whose PA are limited to those included in the compulsory PE curriculum.


The relevance of the study is linked to three primary considerations: (1) studies thus far have not assessed the effect of recreational soccer as an intervention for CMRF in obese children. (2) a comprehensive and sensitive set of indicators of CMRF will be used. (3) a highly popular sport that is socially and culturally meaningful and accessible to all social strata will be used for the prevention of childhood obesity and CMRF.