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This systematic review aimed to synthesize evidence of cross-sectional studies on the associations between physical activity, cardiometabolic risk factors and vitamin D concentrations in children and adolescents. The search was performed in PubMed, SciELO, LILACS, Scopus, MEDLINE and SPORTDiscus. Cardiometabolic risk factors included obesity, insulin resistance, systemic arterial hypertension and unfavorable changes in the lipid profile (low levels of high-density lipoprotein, elevated low-density lipoprotein and triglycerides). Cross-sectional design studies published between 2007 and 2019 were included whether they evaluated the relationship between vitamin D and physical activity and/or vitamin D and cardiometabolic risk factors. Fourteen studies were selected, involving 8340 children and adolescents. The main results found were a significant inverse relationship between vitamin D levels and cardiometabolic risk factors. All studies (n = 8) that tested association between physical activity and 25-hydroxyvitamin D (25 (OH) D) concentrations showed a significant and direct relationship between them. In addition, nine out of eleven studies that tested the association between 25 (OH) D and body mass index reported an inverse and significant relationship between 25 (OH) D and obesity. In conclusion, sufficient concentrations of vitamin D are related to a more favorable cardiometabolic profile, and children and adolescents who are obese or insufficiently active have a higher risk of present hypovitaminosis D.

PURPOSE: Recently, doubts have been raised concerning the validity of the 20-m shuttle run test (20mSRT) to predict cardiorespiratory fitness (CRF) in youth. Despite these doubts, authors continue to provide powerful evidence that CRF can be predicted reliably using the 20mSRT albeit using contrasting models. Therefore, we aimed to compare a new linear model with an alternative allometric model to predict CRF (peak oxygen uptake, 𝑉 ̇O2peak) using 20mSRT. METHODS:The study included 148 adolescents (43% girls), aged 13.37 ± 1.84 years.Adolescents were randomly assigned to validation (n = 91) and cross-validation (n = 57) groups.𝑉 ̇O2peak was measured using a gas analyser in both maximal exercise tests in the laboratory as well as 20mSRT. Multiple linear regression methods were applied to develop the linear models using 20mSRT (Laps), BMI and body fat percentage. Alternative allometric models were also proposed/fitted using 20mSRT (Laps), height and body mass. RESULTS:The criterion validity of both the linear and the allomeric models were found to be acceptable R 2 =82.5% and 82.7% respectively, providing reassuring evidence that the 20mSRT can be used with confidence to predict CRF. However, the allometric model identified a heightto-mass ratio, not dissimilar to the inverse BMI (known to be a measure of leanness), to be associated with CRF. The allometric model also revealed that the rise in energy cost (𝑉 ̇O2peak) with increasing laps was exponential. This will more accurately reflect the non-linear rise in energy demand of shuttle running as the test progresses to exhaustion. CONCUSIONS: These observations provided powerful evidence that allometric models are more than satisfactory in terms of both criterion AND construct validity when predicting CRF (𝑉 ̇O2peak) using the 20mSRT.

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Objective Study aimed to evaluate the effect and individual responsiveness after 12-weeks of high-intensity interval training (HIIT) and moderate-intensity of continuous training (MICT) on adiponectin, cardiometabolic risk factors and physical fitness in overweight adolescents. Methods Participated 52 adolescents, both sexes, 11 and 16 years-old: HIIT (n = 13), MICT (n = 15) and control group (CG, n = 24). Body mass, height, waist circumference (WC), fat mass (FM), fat-free mass (FFM), blood pressure, high-density lipoprotein (HDL-c), low-density lipoprotein (LDL-c), triglycerides, insulin, adiponectin, and C-reactive protein (CRP) were evaluated. Body mass index z-score (BMI-z), waist-to-height ratio (WHtR), insulin resistance and insulin sensitivity were calculated. Resting heart rate (HRrest), peak oxygen consumption (VO2peak), right handgrip strength (HGS-right), left handgrip strength (HGS-left) and abdominal resistance (ABD) was evaluated. HIIT session lasted around 35min and MICT of 60min of exercises on stationary bicycle, three times a weekday for 12-weeks. ANOVA, effect size, and prevalence of responders were used for statistical analysis. Results HIIT reduced BMI-z, WHtR, LDL-c and CRP, while increased of physical fitness. MICT reduced HDL-c, while increased of physical fitness. CG reduced FM, HDL-c, and CRP, while increased FFM and HRrest. Frequencies of respondents in HIIT were observed for CRP, VO2peak, HGS-right and HGS-left. Frequencies of respondents in MICT were observed for CRP and HGS-right. Frequencies of no-respondents in CG were observed for WC, WHtR, CRP, HRrest and ABD. Conclusion Interventions with exercises were effective to adiposity, metabolic health, and physical fitness improvements. Individual responses were observed in inflammatory process and physical fitness, important changes in overweight adolescent’s therapy.

Introdução: O comportamento sedentário tem sido motivo de preocupação para os pesquisadores no mundo, especialmente no Brasil. Objetivo: Este estudo comparou a atividade física moderada-vigorosa e o comportamento sedentário em dois anos de dois levantamentos (2008 e 2017), relacionando esses comportamentos à circunferência abdominal. Métodos: Estudo transversal, com 1.783 alunos, de ambos os sexos, com idade entre 10 e 17 anos: 2008 (n = 977) e 2017 (n = 806). Os estudos foram realizados em escolas públicas de um município do sul do Brasil. O nível de atividade física foi avaliado por meio de um questionário de gasto energético. A circunferência abdominal foi considerada alta ≥ 75º percentil para idade e sexo. Os estudantes foram agrupados de acordo com os níveis de atividade física moderada-vigorosa. O tempo sentado foi considerado comportamento sedentário. Resultados: A proporção de meninos ativos em 2008 (62,2%) foi maior do que em 2017 (34,1%; p <0,001), enquanto a frequência de obesidade abdominal foi maior em 2017 (meninos 36,3%, meninas 25,5%) do que em 2008 (15,7% e 10,5%; p <0,001, respectivamente). Em 2017, houve um aumento de 2,8 vezes no risco de prevalência de circunferência abdominal aumentada em relação a 2008 (p <0,001), que foi diretamente relacionado ao aumento de 16,5 vezes no risco de comportamento sedentário elevado (p <0,001) e duas vezes de aumento em quem pratica atividade física moderada-vigorosa < 60min / dia (p <0,001). Conclusão: O risco de obesidade abdominal aumentou na última década em ambos os sexos, o que parece ser principalmente devido ao comportamento sedentário, além do menor nível de atividade física moderada-vigorosa em meninos.