Abstract This article aims to present growth curves for height, weight, and BMI of 95,000 Brazilian youths aged 6 to 17 years, including the five regions of the country, the Amazon region, and indigenous populations, and compare them with the World Health Organization (WHO) growth references. The final sample consisted of 52,729 boys and 42,731 girls from the “Projeto Esporte Brasil” database. Body mass and height information were used to derive the curves. The generalized additive model for location, scale, and shape was employed. In this study, we present smoothed weight-for-age, height-for-age, and BMI-for-age curves for boys and girls. Differences were observed between the results of the Brazilian curves and the WHO growth references. The developed curves will be valuable for professionals in medicine, public health, nutrition, physical education, and other related fields, regarding the assessment of physical growth in Brazilian children and adolescents and monitoring the nutritional status of this population. Additionally, these curves will facilitate the identification of individuals or subgroups at risk of diseases and delayed growth, with a greater focus on specific country-related factors.

Resumo O objetivo do artigo é apresentar curvas de crescimento de altura, peso e IMC de 95.000 jovens brasileiros com idades entre 6 e 17 anos, incluindo as cinco regiões do país, a região da Amazônia e os povos indígenas, e comparar com as referências de crescimento da Organização Mundial da Saúde (OMS). A amostra final foi composta por 52.729 meninos e 42.731 meninas provenientes do banco de dados do “Projeto Esporte Brasil”. As informações de massa corporal e estatura foram utilizadas para derivar as curvas. O modelo aditivo generalizado para localização, escala e forma foi usado. neste estudo, apresentamos as curvas suavizadas de peso-idade, altura-idade e IMC-idade para meninos e meninas. Foram observadas diferenças entre os resultados das curvas brasileiras e as referências de crescimento da OMS. As curvas desenvolvidas serão úteis para profissionais da medicina, saúde pública, nutrição, educação física, entre outros, no que diz respeito a avaliação do crescimento físico de crianças e adolescentes brasileiros e para monitorar o estado nutricional desta população. Além disso, essas curvas permitirão a detecção de indivíduos ou subgrupos em risco de doenças e crescimento retardado, com um foco maior em fatores específicos do país.

RESUMO Este estudo quase-experimental avaliou os efeitos de dois programas de exercício físico, ofertado no contexto das aulas de Educação Física escolar, sobre indicadores de aptidão física. A amostra por conveniência foi composta por 91 alunos com idades entre 9-12 anos que formaram os grupos Formação Corporal (PFC; 45 alunos) e Educação Física (PEF; 45 alunos). Foi mensurado o índice de massa corporal (IMC), aptidão cardiorrespiratória (ApC), flexibilidade e força muscular localizada (FML). Recorreu-se ao “Teste t pareado” e ANOVA de medidas repetidas. O tamanho do efeito foi estimado pelo “eta ao quadrado parcial”, estratificado por sexo, sendo aceito a probabilidade de 5% de erro. Os resultados mostraram nos meninos efeito muito elevado no grupo PFC na ApC, flexibilidade e FML e efeito elevado no grupo PEF na flexibilidade e FML. Nas meninas efeito muito elevado no grupo PFC na ApC, flexibilidade e FML e no grupo PEF efeito muito elevado na flexibilidade e FML e de efeito elevado na ApC. Não houve efeito no IMC em ambos os grupos. Ressaltamos que este único encontro semanal (15 minutos de PFC) foi capaz de apresentar efeito muito elevado e elevado na aptidão física a favor do PFC em ambos os sexos.

ABSTRACT This quasi-experimental study evaluated the effects of two physical exercise programs offered in the context of physical education classes on physical fitness indicators. The convenience sample consisted of 91 students aged 9-12 years who formed the group's Body Training (GBT; 45 students) and Physical Education (PE; 45 students). Body mass index (BMI), cardiorespiratory fitness (CRF), flexibility, and abdominal muscle strength (LMS) were measured. The “Paired t-test” and repeated measures ANOVA were used. The size of the effect was estimated by the “partial squared eta”, stratified by sex, with a 5% probability of an error being accepted. The results showed in boys a very high effect in the PFC group on CRF, flexibility, and FML and a high effect in the PEF group on flexibility and FML. In girls, a very high effect in the GBT group on CRF, flexibility, and FML, and the PE group greatly affected flexibility and FML and had a high effect on CRF. There was no effect on BMI in either group. We emphasize that this single weekly meeting (15 minutes of GBT) was able to have a very high and high effect on fitness in favor of the GBT in both genders.

Abstract Aim: The purpose of this study is to verify the association between sprint, lower limb power, and change of direction speed in schoolchildren. Method: This is a cross-sectional school-based study with a probabilistic sample (n=1455) of adolescents aged 10-17 years. The variables were: sex, chronological age, body mass, height, skinfold sum, maturity offset, lower limb power, change of direction speed, and sprint. For the data analyses, we used a t-test for independent samples, Pearson correlation, and multiple linear regression. A statistical significance level of 5% was considered for all analyses. Results: The three variables of physical fitness presented moderate and significant correlations between them (r = {0.39-0.61}). Three models were tested with sprint (model 1), change of direction sprint (model 2) and lower limb power (model 3) as an outcome. Predictors tested explain 47% of model 1, 49% of model 2, and 54% of model 3. The individual predictor's contribution in both models varied between 0.1% to 38%. Conclusions: The evidence suggests that change of direction speed and sprint, together with sex, body mass, and skinfold sum account for approximately 54% of the variance of lower limb power in adolescents aged 10-17 years.

RESUMO Este estudo objetivou analisar as associações entre diferentes domínios da atividade física (AF) e a dor lombar não específica em adolescentes. Estudo transversal de base escolar realizado com adolescentes de uma cidade do sul do Brasil. Foram analisadas a dor lombar inespecífica, diferentes domínios da AF (deslocamento até a escola, a participação nas aulas de educação física escolar, a participação em escolinhas esportivas e o nível de atividade física geral), sexo, idade, nível socioeconômico e zona de moradia. Participaram do estudo 1.455 adolescentes (50.9% do sexo feminino) com média de idade de 13.5 (±2.02) anos. A prevalência de dor lombar foi de 16.1% (IC95%:14.2-17.9). A não participação nas aulas de Educação Física escolar foi o único domínio da AF a se associar com a presença de dor lombar (OR:2.26; IC95%:1.48-3.47). A não participação nas aulas de Educação Física aumenta a chance de adolescentes apresentarem dor lombar inespecífica.

ABSTRACT This study aimed to analyze the associations between different domains of physical activity (PA) and nonspecific low back pain in adolescents. A school-based study with adolescents randomly selected from a city in the south Brazil. Analyzed variables were nonspecific low back pain, different domains of PA (commuting to school, participation on physical education classes, participation on classes of sports teams, and the general physical activity level), sex, age, socioeconomic status and living area. 1,455 adolescents (50.9% female) with a mean age of 13.5 (± 2.02) years participated of the study. Low back pain prevalence was 16.1% (95% CI: 14.2-17.9). The non-participation in physical education classes was the only domain of PA to be associated with the presence of low back pain (OR: 2.26; 95% CI: 1.48-3.47). Non-participation in Physical Education classes increases the chance of adolescents presenting nonspecific low back pain.

Resumo O objetivo do estudo é identificar a associação da aptidão cardiorrespiratória (ApC) de adolescentes com a atividade física (AF) e as características pedagógicas da educação física escolar (EFi). Avaliaram-se 236 escolares do ensino médio (90 meninos) e seus professores de EFi. Foi feito teste de corrida de seis minutos, foram usados pedômetros, questionário (escolares) e entrevista (professores). Usaram-se unidades de significado e categorização por meio de análise de conteúdo, além do teste t de Student, Anova e regressão linear. A ApC dos escolares que não fazem EFi não difere da dos que fazem (p >0,05). Identificamos a falta de ação dos professores de EFi sobre a promoção da saúde (análise qualitativa). O sexo e a AF predizem 47% da variabilidade da ApC dos escolares (R2: 0,474; p < 0,01).

Abstract The aim of this study is to identify the association of the cardiorespiratory fitness (CRF) of adolescents with physical activity (PA) and the pedagogical characteristics of the School Physical Education (SPE). A total of 236 high school students (90 boys) and their SPE teachers were evaluated. A 6-minute running test, pedometer, questionnaire (students) and interview (teachers) were performed. We used units of meaning and categorization through content analysis, besides the Student's t test, ANOVA and linear regression. The CRF of the students who do SPE do not different who do SPE (p > 0.05). We identified the lack of action of SPE teachers on health promotion (qualitative analysis). Sex and PA predict 47% of the school's CRF variability (R2: 0.474, p < 0.01).

Resumen El objetivo del estudio fue identificar la asociación de la aptitud cardiorrespiratoria (ApC) de adolescentes con la actividad física (AF) y las características pedagógicas de la educación física escolar (EFi). Se evaluó a 236 estudiantes de enseñanza secundaria (90 niños) y a sus profesores de EFi. Se realizó una carrera de 6 minutos, se usaron podómetros, un cuestionario (estudiantes) y una entrevista (profesores). Se utilizaron unidades de significado y categorización mediante análisis de contenido, además de la prueba de la t de Student, Anova y regresión lineal. La ApC de los estudiantes que no realizan EFi no se diferencia de los que la realizan (p >0,05). Identificamos la falta de iniciativa de los profesores de EFi en la promoción de la salud (análisis cualitativo). El sexo y la AF pronostican el 47% de la variabilidad de la ApC de los estudiantes (R2: 0,474; p< 0,01).

Abstract Aim: To verify the associations between organized physical activity out of school (PA) and cardiorespiratory fitness (CRF) with indicators of mental health in children. Methods: This is a cross-sectional study, with a sample of 226 students (47% girls) of public school in the south of Brazil aged between 6 to 11 years-old (8.36 ± 1.46). The cardiorespiratory fitness was measured by running and walking-test in six minutes, following the procedures of the “Brazil Sports Project”. PA was evaluated through a question and the Strengths and Difficulties Questionnaire assessed mental health indicators. Generalized linear regressions were used with a confidence interval of 95%. Results: Total difficulties (β = 2.691; 95%CI, 0.181 to 5.200) and emotional symptoms (β = 1.528; 95%CI, 0.609 to 2.448) were inversely associated with PA. Total difficulties (β = -0.013; 95%CI, -0.022 to -0.003), hyperactivity/attention deficit (β = -0.002; 95%CI, -0.010 to -0.002), and peer relationship problems (β = -0.002; 95%CI, -0.003 to -0.001) were associated with CRF in boys. Conclusion: A total of difficulties and emotional problems presented an inverse association with PA. Further, CRF was inversely associated with total difficulties, hyperactivity-inattention, and peer relationship problems.

Resumo Objetivou-se verificar a associação entre as características da estrutura da escola e a atividade física dos escolares na aula de educação física e no recreio. Estudo de associação com abordagem quantitativa. A amostra aleatória é composta por 176 escolares (71 meninos e 105 meninas) de 10 escolas estaduais de ensino médio da cidade de Passo Fundo-RS, Brasil. A atividade física foi avaliada com pedômetro, posterior a isso se calculou a média do número de passos na aula de educação física e no recreio. As características da estrutura da escola foram avaliadas por observação direta, com a ferramenta de auditoria na escola. Para análise dos dados utilizou-se estatística descritiva, test t independente e regressão linear generalizada. A média do número de passos entre os meninos foi maior quando comparados às meninas na aula de educação física (t=3,478; p<0,001; d cohen= 0,62) e no recreio (t=2,537; p<0,01; d cohen=0,45). O número de passos da aula de educação física não se associou com as características da estrutura da escola. No recreio, foi encontrada uma associação inversa, onde os meninos que estudavam nas escolas com estruturas de qualidade regular, realizaram em média 208,04 (IC 95%=16,44/399,65; p=0,03) passos a mais quando comparados aos meninos das escolas com estruturas de qualidade boa. As escolas que possuem maiores e/ou melhores estruturas, não necessariamente, influenciam os adolescentes na prática de atividade física no recreio e na aula de educação física.

Abstract The aim of this study was to verify the association between the characteristics of the school structure and the physical activity of students in the physical education class and school recess. This is an association study with quantitative approach. The random sample is composed of 176 schoolchildren (71 boys and 105 girls) from 10 schools of the city of Passo Fundo-RS, Brazil. Physical activity was evaluated with a pedometer, after which the average number of steps in the physical education class and school recess was calculated. The characteristics of the school structure were evaluated by direct observation, with the audit tool in the school. Data were analyzed using descriptive statistics, independent t-test and generalized linear regression. The mean number of steps among boys was higher when compared to girls in the physical education class (t=3.478, p<0.001, d cohen=0.62) and in the school recess (t=2.537, p<0.01; d cohen=0.45). The number of steps in physical education class was not associated with the characteristics of the school structure. In the school recess, an inverse association was found, where boys enrolled in schools with regular quality structure performed on average 208.04 (95%CI=16.44/399.65; p=0.03) steps when compared to boys enrolled in schools with good quality structure. Schools that have bigger and/or better structure do not necessarily influence adolescents in the practice of physical activity in school recess and physical education classes.

Resumo O objetivo deste estudo é delinear o perfil da aptidão física relacionada ao desempenho esportivo de crianças e adolescentes brasileiros, estratificado por sexo. Trata-se de um estudo descritivo com corte transversal. As informações são provenientes do Projeto Esporte Brasil (PROESP-Br). A amostra é voluntária, constituída por 8.750 sujeitos avaliados no período entre 2013 e 2015 com idades entre 7 e 17 anos. Foram avaliadas: força de membros inferiores (FMI) através do teste de salto horizontal e superiores (FMS) através do arremesso de mediceball, velocidade através do teste corrida de 20 metros e agilidade através do teste quadrado. As variáveis foram classificadas com os critérios do PROESP-Br. Para o tratamento dos dados foram utilizadas médias, desvios padrão, frequências absolutas e relativas e intervalos de confiança. Os resultados dos meninos mostram que a categoria “fraco” teve a maior prevalência: FMI (40,2%), FMS (29,7%), velocidade (41,4%) e agilidade (37,5%). A categoria “excelente”, como era esperado, teve as menores prevalências FMI (3,7%), FMS (4,9%), velocidade (2,0%) e agilidade (3,5%). Os resultados das meninas foram semelhantes aos dos meninos, onde a categoria “fraco” teve a maior prevalência: FMI (43,7%), FMS (36,8%), velocidade (43,8%) e agilidade (41,0%). A categoria “excelente” também teve as menores prevalências FMI (4,2%), FMS (4,3%), velocidade (1,6%) e agilidade (3,1%). Os resultados indicam que a maioria das crianças e adolescentes brasileiros tem sua aptidão física relacionada ao desempenho esportivo fraca. Dentre as variáveis analisadas a FMI nas meninas e a velocidade nos meninos, foram os componentes com resultados mais desfavoráveis.

Abstract The aim of this study was to outline the physical fitness profile related to sport performance of Brazilian children and adolescents, stratified by sex. This is a descriptive cross-sectional study and information was obtained from the Projeto Esporte Brasil (PROESP-Br). The sample consisted of 8,750 voluntary subjects aged 7-17 years evaluated in the period between 2013 and 2015. The following variables were evaluated: lower limb strength (LLS) through the horizontal jump test and upper limb strength (ULS) through mediceball pitch, speed through the 20-meter sprint test and agility through the square test. Variables were classified with PROESP-Br criteria. For data processing, means, standard deviations, absolute and relative frequencies and confidence intervals were used. The results for boys have shown that the “poor” category had the highest prevalence: LLS (40.2%), ULS (29.7%), speed (41.4%) and agility (37.5%). The “excellent” category, as expected, had the lowest prevalence: LLS (3.7%), ULS (4.9%), speed (2.0%) and speed (3.5%). The results for girls were similar to those of boys, where the “poor” category had the highest prevalence: LLS (43.7%), ULS (36.8%), speed (43.8%) and agility (41.0 %). The “excellent” category also had the lowest prevalence: LLS (4.2%), ULS (4.3%), speed (1.6%) and speed (3.1%). The results indicated that the majority of Brazilian children and adolescents have physical fitness related to sport performance. Among variables analyzed, LLS for girls and speed for boys were the components with the most unfavorable results.

Abstract Pedometers have been used in some studies to measure physical activity in adolescents. However, cutoff points of steps per day that classify physical activity levels are not yet fully established. The aims of this study were to identify the possibility the number of steps/day to predict cardiovascular disease risk factors in adolescents and to propose cutoff points to the number of steps/day for adolescents. Method: 1,045 adolescents (51.7 % girls) aged 11-17 were randomly selected. The number of steps/day was measured using pedometers. The risk factors considered were total cholesterol, systolic and diastolic blood pressure, skinfold thickness and body mass index. The receiver operating characteristics (ROC) curve was used to analyze data. Results: ROC curve results indicated that the number of steps/day was able to predict increased systolic blood pressure in boys (<16,134 steps/day; p=0.006), increased diastolic blood pressure in girls (<12,399 steps/day; p=0.023) and increased total cholesterol in both sexes (<11,788 steps/day for boys; p=0.016 and < 9,400 steps/day for girls; p=0.001). Conclusion: It is possible to identify adolescents that are more likely to have increased total cholesterol and blood pressure by the number of steps/day.