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Purpose: Compare tracking groups with cognitive control functions and plasma brain-derived neurotrophic factors concentrations from childhood to adolescence., Methods: This is a prospective study with 3 years of follow-up. At baseline, data from 394 individuals were collected (11.7 y), and data were obtained from 134 adolescents (14.9 y) at the 3-year follow-up. At both time points, anthropometric and maximal oxygen uptake data were collected. Cardiorespiratory fitness (CRF) groups were classified into high or low CRF. At follow-up, cognitive outcomes were collected via the Stroop and Corsi block test; plasma brain-derived neurotrophic factors concentrations were also analyzed., Results: Comparisons demonstrated that maintaining high CRF over 3 years results in shorter reaction time, better inhibitory control, and higher working memory values. Likewise, the group that moved from low to high CRF over 3 years presented better reaction time. Plasma brain-derived neurotrophic factors concentrations were higher for the group that increased its CRF over the 3 years in relation to the low-low group (90.58 pg·mL-1; P = .004). However, after scaling by an allometric approach, differences were only found for reaction time and working memory between high-high and high-low groups., Conclusion: Maintaining high CRF over 3 years was positively related to reaction time and working memory in relation to adolescents that decreased their levels of CRF.

Purpose: To investigate the association between patterns of sedentary behavior and obesity indicators among adolescents., Methods: This was a cross-sectional study conducted among 389 adolescents (186 boys) aged 10-14 years. Body mass index, body fat (skinfolds), and waist circumference were adopted as outcomes. Sedentary behavior patterns (total time, bouts, and breaks) measured through accelerometry (GT3X and GT3X+; ActiGraph, Pensacola, FL) were adopted as exposures. Peak height velocity, moderate to vigorous physical activity (accelerometer), cardiorespiratory fitness (Léger test), sex, and chronological age were adopted as covariates. Linear regression models adjusted for covariates were used to determine associations between outcome and exposure variables., Results: The mean age of adolescents was 11.8 (0.7) years. Boys were more active than girls (P < .001). Accumulating shorter bouts (1-4 min) of sedentary behavior was negatively associated with body mass index (β = -0.050; 95% confidence interval [CI], -0.098 to -0.003) and waist circumference (β = -0.133; 95% CI, -0.237 to -0.028). Similarly, a higher number of breaks in sedentary behavior were negatively associated with body mass index (β = -0.160; 95% CI, -0.319 to -0.001) and waist circumference (β = -0.412; 95% CI, -0.761 to -0.064)., Conclusion: Shorter bouts of sedentary behavior (1-4 min) and a higher number of breaks of sedentary behavior were associated with lower adiposity. Our findings also suggest that breaking up sedentary time to ensure bouts of sedentary behavior are short might contribute to the prevention of obesity in adolescents.