Abstract Objective: To analyze the content validity and the test-retest reliability of the Questionnaire for Screen Time of Adolescents (QueST). Methods: A study was conducted with high school adolescents from Southern Brazil enrolled in public education (2019). The QueST measures screen time across five constructs: studying, working/internship-related activities, watching videos, playing games, using social media/chat applications. Content validation involved consulting with experts and adolescents to evaluate whether the five constructs were clear and representing screen time behaviors, all ratings were quantified. The experts’ evaluation provided Content Validity Indexes (CVI) for clarity and representativeness of the questionnaire. Students answered the QueST twice (1-week apart), and differences between applications were verified. Test-retest reliability was assessed using Intraclass Correlation Coefficients (ICC) and Bland-Altman analyses. Results: Among the experts, the CVI indicated 94% and 98% of clarity and representativeness, respectively. All items were highly clear for at least 70% of the students. Test-retest reliability was assessed with 104 students (16.3 ± 1.02 years; 66.3% girls). The ICC ranged from 0.41 (95%CI 0.24–0.56) for videos to 0.76 (95%CI 0.66–0.83) for social media/chat applications on weekdays; and from 0.24 (95%CI 0.04–0.41) for videos to 0.67 (95%CI 0.54–0.77) for social media/chat applications on weekends. The lowest mean difference was -4.6 min for working on weekdays, while the highest was 40.6 min for videos on weekends. Conclusions: The QueST proved to be fair to excellent for measuring different screen time constructs. However, the item of videos (weekends) showed poor stability. The QueST demonstrates satisfactory content validity attested by the experts and adolescents.

Resumo Este revisão atualiza dados de comportamento sedentário em crianças e adolescentes brasileiros para o Report Card Brasil 4.0. A busca foi realizada em oito bases de dados (PubMed, Scopus, Web of Science, LILACS, SPORTDiscus, BIREME, Scielo, and Google Scholar) usando os seguintes critérios: artigos originais; amostras incluindo crianças e adolescentes; estudos observacionais que estimaram a prevalência de pelo menos um componente do CS. Nesta atualização foram incluídos 118 estudos (com publicação de 159 artigos), sendo 71 (104 artigos) revisados anteriormente no Report Card 3.0 e 47 estudos (55 artigos) encontrados na atualização de 2018 a 2019. O tempo de tela (34,7%) e de TV (28,2%) continuam sendo os componentes mais investigados, entretanto, dois estudos investigaram o uso de celular e houve aumento em outros comportamentos sedentários, como o tempo sentado (de 9% para 25,6%). Foram encontrados somente quatro estudos com pré-escolares, mas quatro deles cobriam quase todas as idades. O questionário foi o instrumento mais utilizado; no entanto, aumentou o número de estudos usando acelerômetros (de 2 para 8). O ponto de corte mais frequente foi 2 horas/dia (47,5%), mas o uso de outros medidas duplicou. Quase 70% dos estudos relatou que menos de 50% (variação geral: 9,4% a 97,7%) dos adolescentes atendem às recomendações (<2 horas / dia) de comportamento sedentário. A revisão atualizada mostra ainda poucos estudos com pré-escolares e crianças, com o uso de instrumentos validados, com o uso de acelerômetros, com padronização de pontos de corte, e prevalências muito próximas do observado na revisão anterior.

Abstract This review updated data on sedentary behavior in Brazilian children and adolescents for the Brazil’s Report Card 4.0. The searching was carried out in eight databases (PubMed, Scopus, Web of Science, LILACS, SPORTDiscus, BIREME, Scielo, and Google Scholar), based on the the following criteria: original research; samples including Brazilian children and adolescents; to be a observational survey with the prevalence of at least one component of sedentary behavior. In this updated review were included 118 studies (corresponding to 159 papers), being 71 studies (104 papers) previously reviewed in the Report Card 3.0 and 47 studies (55 papers) found in update from 2018 to 2019. Screen time (34.7%) and TV viewing (28.2%) remains the most investigated components, however, two studies investigated cell phone use, and there was an increase in other types of sedentary behavior such as sitting time (from 9% to 25.6%). We found only four studies involving pre-scholars, but four of them covered almost all age groups. Self-reported questionnaire was the instrument more used; however, increased the studies using accelerometers (from 2 to 8 studies). The cut-off point more frequent was 2 hours/day (47.5%), but the use of other measures doubled. Almost 70% of the studies reported that less than 50% (general range: 9.4% to 97.7%) of individuals had < 2 hours/day of sedentary behavior. The updated review found few studies with prescholars and children; using validated instruments; using accelerometers, with standardization of cutoff points, and prevalences very close to what was observed in the previous review.

Resumo A associação da atividade física moderada a vigorosa (AFMV) e do comportamento sedentário (CS) realizados no contexto escolar com fatores de risco cardiovascular é inconclusiva. Assim, o objetivo do presente estudo foi avaliar se a AFMV e o CS realizados durante o período escolar estão associados a fatores de risco cardiovasculares em escolares de 10 a 16 anos. Utilizou-se os dados da linha de base de um estudo clínico controlado não randomizado (“MEXA-SE”) realizado com alunos do 6º ao 9º ano de escolas de Florianópolis, Brasil. Dobras cutâneas, pressão arterial, teste de vaivém de 20 metros, glicemia de jejum, triglicerídeos, colesterol total, lipoproteína de alta densidade e contagem de glóbulos brancos foram mensurados. A AFMV e CS foram medidos objetivamente com acelerômetros. Foi preconizado um período mínimo de 180 minutos de uso para considerar o tempo válido e realizou-se regressão linear múltipla ajustada para idade, sexo e atividade física habitual. A AFMV foi associada positivamente com VO2 pico (β=0,17 ml.kg.min-1) e inversamente associada à soma das quatro dobras cutâneas (β=-0,96 mm), pressão arterial diastólica (β=0,36 mmHg), pressão arterial sistólica (β=-0,301 mmHg); triglicerídeos (β=-1,49 mg.dL-1) e fatores de risco cardiovasculares agrupados (β=-0,123). Houve também associação positiva do CS com fatores de risco cardiovascular agrupados (β=0,033). Conclui-se que a AFMV e o CS foram associados a fatores de risco cardiovasculares. Assim, a promoção de estratégias que visem aumentar a AFMV e reduzir o SB no contexto escolar pode impedir o aparecimento e o acúmulo precoce de fatores de risco cardiovasculares na adolescência.

Abstract The association of moderate to vigorous physical activity and sedentary behavior performed in the school context with cardiovascular risk factors is unclear. Thus, the purpose of this study was to evaluate whether MVPA and SB during school time are associated with single and clustered cardiovascular risk factors in 10- to 16-year-old school students. This study used the baseline data from a non-randomized controlled clinical trial (“MEXA-SE”) conducted on 6th to 9th-grade students from schools in Florianopolis, Brazil. Skinfolds, resting blood pressure, 20-m shuttle-run test, fasting glucose, triglycerides, total cholesterol, high-density lipoprotein cholesterol, and white blood cell counts were obtained. MVPA and SB were objectively measured with accelerometers. A minimum of 180 minutes was considered valid school-time for analysis. Multiple linear regression adjusted for age, sex and habitual physical activity was used. School-time MVPA was positively associated with the peak VO2 (β = 0.17 ml.kg.min-1), and inversely associated with sum of four skinfolds (β = -0.96 mm), diastolic blood pressure (β = -0.36 mmHg), systolic blood pressure (β = -0.301 mmHg); triglycerides (β = -1.49 mg.dL-1), and clustered cardiovascular risk factors (β = -0.123). School-time SB was positively associated with clustered cardiovascular risk factors (β = 0.033). In conclusion, independently of habitual physical activity level, school-time MVPA and a lower time in SB were associated to single and clustered cardiovascular risk factors. Thus, the promotion of strategies aimed increase MVPA and reduce SB at school may prevent the onset and early accumulation of cardiovascular risk factors in adolescence.

Resumo Os objetivos do estudo foram examinar as mudanças na prevalência de sobrepeso e obesidade entre os estudantes de 2001 a 2011 e verificar se essas alterações diferem de acordo com a faixa etária, a área de residência e a renda familiar. Analisamos dois levantamentos transversais realizados em 2001 e 2011 com adolescentes brasileiros. As características sociodemográficas e antropométricas foram autorrelatadas por meio de um questionário. Regressão logística multinomial foi utilizada para analisar as mudanças no sobrepeso e obesidade entre os dois inquéritos. O estado nutricional foi considerado o desfecho do presente estudo e os inquéritos (2001 e 2011) foram as exposições. As razões de chance de sobrepeso e obesidade foram maiores entre os meninos e meninas em áreas urbanas no inquérito de 2011 em comparação com 2001. Meninos e meninas com maior renda também apresentaram maior chance de sobrepeso e obesidade no segundo inquérito. Sugerimos que futuras intervenções considerem a área de residência e a renda familiar para fortalecer a eficácia das ações desenvolvidas para prevenir e controlar esses indicadores entre os adolescentes.

Abstract The aims were to examine changes in the prevalence of overweight and obesity among students from 2001 to 2011, and to verify if these changes differ according to age group, area of residence, and family income. We analyzed two cross-sectional surveys conducted in 2001 and 2011 with brazilian adolescents. Sociodemographic and anthropometric characteristics were self-reported using a questionnaire. Multinomial logistic regression was used to analyze changes in overweight and obesity between the two surveys. The nutritional status was the outcome of the present study and the surveys (2001 and 2011) were the exposure. The odds of being overweight and obese were higher among boys and girls in urban areas in the 2011 survey compared to the 2001. Boys and girls with higher income were also more likely to present overweight and obesity in the second survey compared to the first. An increase of overweight and obesity was observed over a decade. We suggest that future interventions consider the area of residence and the family income to strengthen the effectiveness of actions developed to prevent and control these indicators among adolescents.

Resumo Os objetivos do estudo foram examinar as mudanças na prevalência de sobrepeso e obesidade entre os estudantes de 2001 a 2011 e verificar se essas alterações diferem de acordo com a faixa etária, a área de residência e a renda familiar. Analisamos dois levantamentos transversais realizados em 2001 e 2011 com adolescentes brasileiros. As características sociodemográficas e antropométricas foram autorrelatadas por meio de um questionário. Regressão logística multinomial foi utilizada para analisar as mudanças no sobrepeso e obesidade entre os dois inquéritos. O estado nutricional foi considerado o desfecho do presente estudo e os inquéritos (2001 e 2011) foram as exposições. As razões de chance de sobrepeso e obesidade foram maiores entre os meninos e meninas em áreas urbanas no inquérito de 2011 em comparação com 2001. Meninos e meninas com maior renda também apresentaram maior chance de sobrepeso e obesidade no segundo inquérito. Sugerimos que futuras intervenções considerem a área de residência e a renda familiar para fortalecer a eficácia das ações desenvolvidas para prevenir e controlar esses indicadores entre os adolescentes.

Abstract The aims were to examine changes in the prevalence of overweight and obesity among students from 2001 to 2011, and to verify if these changes differ according to age group, area of residence, and family income. We analyzed two cross-sectional surveys conducted in 2001 and 2011 with brazilian adolescents. Sociodemographic and anthropometric characteristics were self-reported using a questionnaire. Multinomial logistic regression was used to analyze changes in overweight and obesity between the two surveys. The nutritional status was the outcome of the present study and the surveys (2001 and 2011) were the exposure. The odds of being overweight and obese were higher among boys and girls in urban areas in the 2011 survey compared to the 2001. Boys and girls with higher income were also more likely to present overweight and obesity in the second survey compared to the first. An increase of overweight and obesity was observed over a decade. We suggest that future interventions consider the area of residence and the family income to strengthen the effectiveness of actions developed to prevent and control these indicators among adolescents.

Resumo Objetivou-se sintetizar estudos que estimaram a prevalência de comportamento sedentário (CS) em crianças e adolescentes. Revisão sistemática conduzida em oito base de dados (PubMed, Scopus, Web of Science, LILACS, SPORTDiscus, BIREME, Scielo, and Google Scholar). Os critérios utilizados foram: artigos originais; amostras incluindo crianças e adolescentes; levantamentos de base escolar e populacional; estudos observacionais usando diferentes medida do CS; estudos mostrando a prevalência de pelo menos um componente do CS. Dos 205 estudos incluídos, 104 foram analisados. Houve maior concentração de estudos nas regiões Sul (n=41) e Nordeste (n=18). Os componentes mais investigados foram assistência à TV (n=36) e tempo de tela (n=32). Somente três estudos incluíram dados de crianças com menos de sete anos, e a maioria investigou adolescentes de 10 a 19 anos. A maioria dos estudos usou questionários e apresentou variabilidade no ponto de corte utilizado (de 2 a 4 horas). A prevalência de adolescentes que atendiam às recomendações de CS (<2 horas/dia) variou de 9,4% a 68,0%. A prevalência de adolescentes que assistiam TV (<2 horas/dia) foi de 16,8% a 67,2%. Para o uso de computador, a prevalência variou de 39,1% a 97,7%; e de 47,7% a 98,0% para o videogame. Na maioria dos estudos menos da metade dos adolescentes atendeu às recomendações de CS e de tempo de TV. Por outro lado, mais da metade deles apresentou tempo inferior a duas horas por dia para o uso de computador e videogame.

Abstract The aim of this study was to summarize studies examining the prevalence of sedentary behavior among Brazilian children and adolescents. A systematic review conducted on eight databases (PubMed, Scopus, Web of Science, LILACS, SPORTDiscus, BIREME, Scielo, and Google Scholar). The criteria applied were: original research; samples including Brazilian children and adolescents; to be a school- or population-based survey; observational studies using different measures of sedentary behavior; studies showing the prevalence of at least one component of sedentary behavior. Of the 205 studies included, 104 were analyzed. There was a greater concentration of studies in the southern (n=41) and northeastern (n=18) regions. The components more frequently investigated were watching TV (n=36) and screen time (n=32). Only three studies included children under seven years, and the age range more investigated was 10 to 19 years. Most of the studies used a self-reported questionnaire and showed variability in the cut-off point applied (from 2 to 4 hours/day). The prevalence of adolescents who met recommendations ranged from 9.4% to 68.0% for sedentary behavior (<2 hours/day) and from 16.8% to 67.2% for TV viewing (<2 hours/day). The prevalence ranged from 39.1% to 97.7% for computer use and from 47.7% to 98.0% for videogame use. Most of the studies reported that less than half of the adolescents met the recommendations of sedentary behavior and TV viewing. On the other hand, more than half of them devoted less than two hours a day to computer and videogame use.

Abstract Aims: To investigate the presence of a relative age effect (RAE) and the influence of birth quarters (BQ), semesters (S) as well as skeletal maturation on anthropometric characteristics and aerobic peak speed (PST-CAR) in youth male soccer players. Methods: One hundred players were recruited to participate in this study. Players were allocated into 4 BQ’s and 2 S. Skeletal maturity status was assessed using the Fels method. Assessments for players included determination of body size and composition and PST-CAR. Results: Overall, more players were born in BQ1 (38 %) and S1 (75%). The likelihood of players born in BQ1 and BQ2 being selected was 3.61 to 4.96 times higher than players in BQ3 and BQ4. Players in BQ4 maturing earlier were biologically older than their peers in BQ1. The players in BQ3 and S2 displayed higher PST-CAR compared with players in BQ2 and S1, respectively. However, players of contrasting skeletal maturity status did not differ in aerobic performance. Conclusion: Our findings indicate that coaches and talent scouts are systematically retaining average and early maturing players born in S1 and excluding late maturing players born in BQ4. However, aerobic performance appeared to be dependent on the relative age, but independent of skeletal maturation during puberty.