The reasons why athletes, especially young people, seek to adhere to sports practice has aroused the interest of research. The aim of this study was to identify the reasons for the sports practice of young soccer and volleyball athletes according to gender, age, family economic class, practice time and level of competitiveness. 188 athletes, 56 volleyball athletes and 132 soccer players aged 10-16 participated in the study. The reasons for the sport were identified through the Participation Motivation Questionnaire (PMQ). The data were analyzed through Covariance Analysis. The results indicated that, in general, the most important reason for sports practice was “Technical Competence” (4.51±0.54), followed by factors of intermediate importance: “Competition” (4.30±0.73), “Group Activity” (4.29±0.71) and “Physical Fitness” (4.25±0.64). Low-income families (C) attributed greater importance to the motivation factors related to “Social Recognition” and “Group Activity”. Athletes with lower practice time conceded less relevance to “Group Activity” and “Affiliation”, while those with a national competitive level demonstrated greater importance to all motivation factors, with the exception of “Competition.” Young athletes have been motivated to practice sports, especially for reasons related to self-realization, improvement of technical skills and overcoming challenges. Differences were also identified between family economic class groups, practice time and competitive level in the motivation factors for sports practice.

Introduction: In view of the growing prevalence of childhood excess weight and obesity In Brazil In recent decades, it is necessary to observe how this phenomenon occurs in the period of transition to adolescence. Objective: To verify the tracking of excess weight between childhood and adolescence in schoolchildren of both sexes. Methods: The study has a longitudinal design and the data used are part of a prospective study carried out from 2002 to 2005. Participants included 397 schoolchildren of both sexes (211 boys and 186 girls). The nutritional status was determined by the body mass index, and the participants were divided into the following groups: Normal Weight to Normal Weight, Normal Weight to Excess Weight, Excess Weight to Excess Weight, Excess Weight to Normal Weight. The tracking was analyzed using the intraclass correlation coefficient (ICC) and Kappa (k) index. Results: A significant difference (P <0.05) was observed between all variables (age and anthropometric indicators) between 2002 and 2005 for boys and girls. The ICC indicated tracking classified as high (ICC = 0.87) for the BMI values, and the tracking percentage showed that 87% of the subjects remained in the same category of normal weight and excess weight. The values of k = 0.68 show good tracking (P <0.001), indicating a strong maintenance of the subjects in the normal and excess weight categories. Conclusion: The tracking percentage was high, indicating that both boys and girls maintained the classification of excess weight during the period analyzed. Level of Evidence II; Lesser quality prospective study (eg, patients enrolled at different points in their disease or <80% followup).

The present study objectively measured the pattern of sedentary behavior among schoolchildren from a city in southern Brazil. A probabilistic sample composed of 394 adolescents was selected from ten public schools in the city of Londrina/PR. The cut-point of 720 counts.min -1 for the vector magnitude from the ActiGraph accelerometer was used to estimate the total sedentary time, bouts (1-4 min, 5-9 min, 10-14 min, 15-29 min, and ≥ 30 min), and breaks during the week, on weekdays and at weekends, as well as at school and out of school. Adolescents spent about 10 hours per day in sedentary behavior. Total sedentary time in bouts was 50% (278 from 535 minutes) in short bouts. Adolescents demonstrated greater time in shorter bouts (< 10 minutes) within the school period and longer time in extended bouts (≥ 15 minutes) outside school (p < 0.05). Sex and socioeconomic status had no effect on sedentary time regarding bouts and number of breaks. Thus, Brazilian adolescents present high levels of sedentary time, especially during time outside school.

Background Working memory performance is associated with better academic achievements in children and adolescents, and it is positively related to CRF. However, what level of cardiorespiratory fitness (CRF) discriminates higher working memory performance is not known. The purpose of this study was to identify CRF thresholds linked to working memory in adolescents. Methods Data of 141 adolescents (53.2 % girls) were collected (14.9 years) from a cross-sectional study during the year 2019. CRF was assessed by the 20-m shuttle run test, and maximal oxygen uptake was calculated using the Mahar´s equation. Working memory was evaluated by the Corsi blocks test and performance was classified by percentiles. Receiver operating characteristic (ROC) curve analysis was used to identify CRF thresholds. Results The ROC analysis indicated that CRF could be used to discriminate working memory in adolescents. CRF thresholds of ≥45.03 ml.kg− 1.min− 1for boys and ≥36.63 ml.kg− 1.min− 1for girls were found to be indicative of “normal” working memory performance. Conclusions CRF could discriminate low and normal working memory performance in 14-16- year-old adolescents. These thresholds could allow for earlier identification and intervention of low working memory performance using CRF.

Background Although many studies found a positive association between physical activity (PA) and academic performance (AP), most did not consider important variables of school setting and students’ self-concept. Aims To analyze the association between moderate-to-vigorous PA (MVPA) and AP in adolescents, considering potential confounding variables of school setting and self-concept in adolescents. Method The final sample was composed of 394 students (186 boys) with a mean age of 11.3 ( SD = 0.8) years. The school grades were used as an indicator of AP. Measurements of body mass and stature were collected, and the body mass index was calculated and converted into z-score values. Maternal education, socioeconomic status, self-concept, and variables of the school setting were self-reported. MVPA and sedentary behavior (SB) were measured through accelerometry (GT3X and GT3X+; ActiGraph, Pensacola, Florida). Multiple linear regression was used for the association analyses, adopting p < .05. Results MVPA was inversely associated with global AP and mathematics only for girls: β = −.105 (95% CI [−0.205, −0.006]; p = .038); β = −.136 (95% CI [−0.261, −0.011]; p = .033). After adjusting for the school setting and self-concept, these significant associations disappear. Discussion MVPA was inversely associated with global AP and mathematics only for girls regardless of age, z-score body mass index, maternal education, socioeconomic status, and SB. However, after adjusting for school setting and self-concept, theses association disappear in mathematics and global AP, respectively. Conclusion The device-measured MVPA was not associated with AP after controlling for important variables (school setting and self-concept).