ABSTRACT Objective: This study aimed to verify the association between childhood anthropometric indicators and areal bone mineral density (aBMD) in adulthood. Methods: Repeated measures of 137 subjects (68 females) were obtained in childhood (9.2±1.5 years of age) and adulthood (22.3±1.7 years of age). aBMD (g/cm2) was assessed for whole body, lumbar spine, upper and lower limbs, and femoral neck in adulthood using dual-energy X-ray absorptiometry. Anthropometric measurements of body weight (BW), height, triceps and subscapular skinfolds were obtained in childhood. The anthropometric indicators used were BW, body mass index (BMI), and sum of skinfolds (ΣSF). Simple linear regression was used to assess the association between childhood anthropometric indicators and aBMD in adulthood, controlled by chronological age and stratified by sex, with 5% statistical significance. Results: In females, multiple associations were observed between anthropometric indicators and aBMD, with higher coefficients for BMI (β=0.020; R2=0.20; p<0.01 for right femoral neck to β=0.008; R2=0.16; p<0.01 for upper limbs), followed by BW (β=0.003; R2=0.21; p<0.01 for upper limbs to β=0.008; R2=0.20; p<0.01 for right femoral neck) and ΣSF (β=0.001; R2=0.06; p<0.01 for upper limbs to β=0.005; R2=0.12; p<0.01 for right femoral neck). In males, associations were observed only for the lumbar spine region (β=0.016; R2=0.09 for BMI to β=0.004; R2=0.06; p<0.01 for ΣSF). Conclusions: Anthropometric indicators of childhood proved to be sensitive predictors of aBMD in adulthood, especially in females. BMI indicated a greater association with aBMD in both sexes.

RESUMO Objetivo: O objetivo do estudo foi verificar a associação entre os indicadores antropométricos da infância com a área da densidade mineral óssea (aDMO) na idade adulta. Métodos: Medidas repetidas de 137 sujeitos (68 do sexo feminino) foram obtidos na infância (9,2±1,5 anos de idade) e idade adulta (22,3±1,7 anos de idade). A aDMO (g/cm2) foi avaliada para todo o corpo, coluna lombar, membros superiores e inferiores e colo do fêmur na idade adulta usando a absorciometria radiológica de dupla energia (DXA). Medidas antropométricas de peso corporal, estatura e dobras cutâneas das regiões tricipital e subescapular foram obtidas na infância. Os indicadores antropométricos utilizados para as análises foram o peso corporal (PC), o índice de massa corporal (IMC) e o somatório de dobras cutâneas (ΣDC). Regressão linear simples controlada pela idade e estratificada por sexo foi empregada para avaliar a associação entre os indicadores antropométricos do período da infância na aDMO na idade adulta, com significância estatística de 5%. Resultados: No sexo feminino, múltiplas associações foram observadas entre os indicadores antropométricos e a aDMO, com maiores coeficientes para IMC (β=0,020; R2=0,20; p<0.01 para colo do fêmur direito a β=0,008; R2=0,16; p<0,01 para membros superiores), seguido da PC (β=0,003; r2=0,21; p<0,01 para membros superiores a β=0,008; r2=0,20; p<0,01 para colo do fêmur direito) e ΣDC (β=0,001; R2=0,06; p<0,01 para membros superiores a β=0,005; R2=0,12; p<0,01 para colo do fêmur direito). No sexo masculino, associações ocorreram apenas na região da coluna (β=0,016; R2=0,09 para IMC a β=0,004; R2=0,06; p<0,01 para ΣDC). Conclusões: Indicadores antropométricos da infância mostraram ser sensíveis preditores da aDMO na idade adulta, especialmente no sexo feminino. O IMC indicou maior associação com a aDMO em ambos os sexos.

Resumo Nosso objetivo foi analisar a associação combinada entre características dos pais e indicadores de adiposidade dos filhos com o risco metabólico em adolescentes. Foi realizado estudo transversal com 972 adolescentes e seus pais. Observamos que adolescentes com sobrepeso que possuem mãe com peso normal apresentaram menor risco metabólico em comparação com seus pares com mães que apresentam sobrepeso. Concluímos que o status de peso da mãe modera a relação entre indicadores de obesidade e risco metabólico dos adolescentes.

Abstract Our aim was to analyze the joint association of parental characteristics and offspring obesity indicators with metabolic risk in adolescents. A cross-sectional study was carried out with 972 adolescents and their parents. We observed that overweight adolescents who have a normal weight mother show lower metabolic risk in comparison with their counterparts with overweight mothers. In conclusion, mother’s weight status moderates the relationship between offspring’ obesity indicators and metabolic risk in adolescents.

Resumo Nosso objetivo foi analisar a associação combinada entre características dos pais e indicadores de adiposidade dos filhos com o risco metabólico em adolescentes. Foi realizado estudo transversal com 972 adolescentes e seus pais. Observamos que adolescentes com sobrepeso que possuem mãe com peso normal apresentaram menor risco metabólico em comparação com seus pares com mães que apresentam sobrepeso. Concluímos que o status de peso da mãe modera a relação entre indicadores de obesidade e risco metabólico dos adolescentes.

Abstract Our aim was to analyze the joint association of parental characteristics and offspring obesity indicators with metabolic risk in adolescents. A cross-sectional study was carried out with 972 adolescents and their parents. We observed that overweight adolescents who have a normal weight mother show lower metabolic risk in comparison with their counterparts with overweight mothers. In conclusion, mother’s weight status moderates the relationship between offspring’ obesity indicators and metabolic risk in adolescents.

Abstract Aims: This study aimed to compare the sedentary time measured using the ActiGraph GT3X accelerometer with the measurement of sitting and standing time obtained by ActivPAL inclinometers. Methods: This was a cross-sectional study conducted with a sample of 60 schoolchildren (34 males) of one elementary public school in Brazil. The students used both an ActiGraph GT3X accelerometer and an ActivPAL inclinometer, concurrently, positioned at the beginning and removed at the end of the school shift, for four days. For analysis, paired Student's t-tests, Pearson's correlation coefficients, intraclass correlation coefficients, and Bland-Altman plots were used. Results: When comparing sedentary time with sitting time, although correlated (r = 0.53; p < 0.001), the mean minutes were different (134.2 min/day in ActiGraph GT3X vs 120.3 min/day in ActivPAL; p < 0.001), with a bias of 13.9 min/day. When comparing the measurement of sedentary time with the sum of the sitting time plus standing time, different mean minutes were also observed (134.2 min/day in ActiGraph GT3X vs 177.0 min/day in ActivPAL; p < 0.001), and although the correlation was stronger (r = 0.75; p < 0.001), the bias was higher (−42.8 min/day). Conclusion: Sedentary time derived from the ActiGraph GT3X device should be used with caution to evaluate sedentary behavior in a school setting and may be interpreted only as non-moving activities (stationary behavior).

Resumo Objetivo: Analisar a associação entre o padrão do tempo sedentário (bouts e breaks) e o desempenho acadêmico, com ênfase no papel mediador do autoconceito. Métodos: Participaram deste estudo transversal 394 adolescentes (208 moças), de 10 a 14 anos, da sexta série de Londrina, Paraná, Brasil. O padrão do tempo sedentário foi obtido por meio de acelerometria. Definições: bouts sedentários — períodos ininterruptos em comportamento sedentário; breaks — período não sedentário entre duas séries sedentárias. O autoconceito foi estimado usando o Inventário Piers-Harris II. O desempenho acadêmico foi obtido pelas notas escolares. Resultados: Bouts sedentários curtos foram associados com maior desempenho acadêmico em rapazes (1–4 minutos: β=0,035, p=0,007) e moças (1–4 minutos: β=0,031, p=0,014; 5–14 minutos: β=0,054, p=0,001). Bouts longos (30 minutos) foram associados a menor desempenho acadêmico em rapazes (β=-0,023; p=0,011) e moças (β=-0,032; p<0,001). Para as moças, o autoconceito total e intelectual mediou a associação entre todos os padrões sedentários e o desempenho acadêmico (bouts de 1–4 minutos [total: 39% e intelectual: 42,8%]; bouts de 5–14 minutos [total: 21,5% e intelectual: 35,4%]; bouts ≥30 minutos [total: 22,6% e intelectual: 32,3%]; e breaks [total: 38,9% e intelectual: 40,7%]). Para os rapazes, o autoconceito total (56,4%) e intelectual (82,9%) mediaram apenas a associação entre bouts de 5–14 minutos e desempenho acadêmico. Conclusões: O padrão do tempo sedentário está associado ao desempenho acadêmico em adolescentes, e essa associação é mediada pelo autoconceito, principalmente em moças.

Abstract Objective: To analyze the association between the pattern of sedentary time (bouts and breaks) with academic performance, with an emphasis on the mediating role of self-concept. Methods: Participants in the cross-sectional study were 394 adolescents (208 girls), aged 10–14 years, from sixth grade from Londrina, Paraná, Brazil. The sedentary time pattern was measured through accelerometry. Definitions: sedentary bouts — uninterrupted periods of sedentary behavior; breaks — non-sedentary period between two sedentary bouts. The self-concept was estimated using the Piers-Harris II Inventory. Academic performance was obtained by school grades. Results: Short sedentary bouts were associated with higher academic performance in boys (1–4 minutes: β=0.035, p=0.007) and girls (1–4 minutes: β=0.031, p=0.014; 5–14 minutes: β=0.054, p=0.001). Long bouts (30 minutes) were associated with lower academic performance in boys (β=-0.023; p=0.011) and girls (β=-0.032; p<0.001). For girls, total and intellectual self-concept mediated the association between all sedentary pattern and academic performance (bouts 1–4 minutes [total: 39% and intellectual: 42.8%]; bouts 5–14 minutes [total: 21.5% and intellectual: 35.4%]; bouts ≥30 minutes [total: 22.6% and intellectual: 32.3%]; and breaks [total: 38.9% and intellectual: 40.7%]). For boys, the total (56.4%) and intellectual (82.9%) self-concept mediated only the association between bouts of 5–14 minute and academic performance. Conclusions: The pattern of sedentary time is associated with academic performance in adolescents and this association is mediated by self-concept, especially in girls.

Resumo Apesar das mudanças observadas nos relacionamentos sociais nos últimos anos, especialmente entre as gerações mais novas, pouca evidência está disponível sobre os fatores associados à percepção dos relacionamentos sociais. Neste estudo nós investigamos a associação entre a percepção das próprias relações sociais, comportamentos associados à saúde, maturação biológica e indicadores de saúde mental em adolescentes. Este é um estudo transversal conduzido com 1.336 adolescentes (605 meninos e 731 meninas) com idades entre 10 e 17 anos, alunos de escolas públicas. A percepção dos relacionamentos sociais (família, amigo e professores), frequência de sentimentos de estresse e tristeza, o desempenho acadêmico, consumo de álcool, tabaco e alimentos gordurosos, bem como o nível de atividade física e tempo de tela foram avaliados por questionário. A maturação biológica foi estimada a partir do pico de velocidade de crescimento. Observamos que as piores relações sociais percebidas estiveram relacionadas ao consumo de tabaco (família e professores), de álcool (professores), alto consumo de alimentos gordurosos (professores), sentimentos de estresse (família e professores) e de tristeza (família e amigos) mais frequentes, e pior percepção do desempenho acadêmico (amigos e professores).

Abstract Although changes have been observed in social relationships in the recent years, especially among younger generations, little evidence is available concerning factors associated with adolescents’ perceived social relationships. In this study we investigated the association between self-perceived social relationships, health-related behaviors, biological maturation, and mental health in adolescents. This is a cross-sectional study conducted with 1,336 adolescents (605 boys and 731 girls) aged between 10 to 17 years from public schools. Self-perceived social relationships (family, friends, and teachers), feelings of stress and sadness, academic performance, tobacco smoking, alcohol and fat consumption, physical activity, and screen time were evaluated by a questionnaire. Biological maturation was assessed by the peak height velocity. We observed that worse perceived social relationships were associated with tobacco smoking (family and teachers), alcohol drinking (teachers), higher consumption of fat (teachers), greater feelings of stress (family and teachers) and sadness (family and friends), and poor academic achievement (friends and teachers).

Resumo Apesar das mudanças observadas nos relacionamentos sociais nos últimos anos, especialmente entre as gerações mais novas, pouca evidência está disponível sobre os fatores associados à percepção dos relacionamentos sociais. Neste estudo nós investigamos a associação entre a percepção das próprias relações sociais, comportamentos associados à saúde, maturação biológica e indicadores de saúde mental em adolescentes. Este é um estudo transversal conduzido com 1.336 adolescentes (605 meninos e 731 meninas) com idades entre 10 e 17 anos, alunos de escolas públicas. A percepção dos relacionamentos sociais (família, amigo e professores), frequência de sentimentos de estresse e tristeza, o desempenho acadêmico, consumo de álcool, tabaco e alimentos gordurosos, bem como o nível de atividade física e tempo de tela foram avaliados por questionário. A maturação biológica foi estimada a partir do pico de velocidade de crescimento. Observamos que as piores relações sociais percebidas estiveram relacionadas ao consumo de tabaco (família e professores), de álcool (professores), alto consumo de alimentos gordurosos (professores), sentimentos de estresse (família e professores) e de tristeza (família e amigos) mais frequentes, e pior percepção do desempenho acadêmico (amigos e professores).

Abstract Although changes have been observed in social relationships in the recent years, especially among younger generations, little evidence is available concerning factors associated with adolescents’ perceived social relationships. In this study we investigated the association between self-perceived social relationships, health-related behaviors, biological maturation, and mental health in adolescents. This is a cross-sectional study conducted with 1,336 adolescents (605 boys and 731 girls) aged between 10 to 17 years from public schools. Self-perceived social relationships (family, friends, and teachers), feelings of stress and sadness, academic performance, tobacco smoking, alcohol and fat consumption, physical activity, and screen time were evaluated by a questionnaire. Biological maturation was assessed by the peak height velocity. We observed that worse perceived social relationships were associated with tobacco smoking (family and teachers), alcohol drinking (teachers), higher consumption of fat (teachers), greater feelings of stress (family and teachers) and sadness (family and friends), and poor academic achievement (friends and teachers).

ABSTRACT BACKGROUND: Overweight and obesity have reached epidemic prevalences. Obesity control involves many factors and needs to begin early in childhood. OBJECTIVES: To ascertain the association between tracked extracurricular sports practice and weight status; and to analyze tracking of overweight and obesity among school-aged children. DESIGN AND SETTING: Prospective cohort study conducted in 13 public schools in Cianorte, Paraná, in 2012-2016. METHODS: The sample comprised 2459 schoolchildren in Cianorte, of mean age 6.3 years at baseline and 9.4 years at follow-up. Body mass index was calculated from body mass and height measurements. The children were grouped as normal weight, overweight or obese. Information on extracurricular sports practice was collected through the dichotomous question “Do you participate in any extracurricular sports?” (“yes” or “no”). RESULTS: Tracking of weight status showed that 75.5% maintained this, with kappa of 0.530. Tracking of extracurricular sports practice showed that 80.9% maintained this, with low concordance (kappa of 0.054). Weight status correlation between baseline and follow-up showed that overweight or obese individuals were 4.65 times (CI: 4.05-5.34) more likely to maintain the same classification or move from overweight to obese at follow-up. Correlation of extracurricular sports practice with overweight or obesity at follow-up was not significant. CONCLUSIONS: These results demonstrated that overweight or obese children were at higher risk of gaining weight than were normal-weight children. In addition, the proportion of these children who maintained extracurricular sports practices over the years was low. Maintenance of this variable was not associated with weight status.

Abstract Aim: The aim was to compare performance in specific-skill tests and motor coordination between groups with different technical efficiency and verify possible variables related to specific skills and motor coordination that contribute to discriminate players into high- and low-technical efficiency. Methods: The sample consisted of 82 young soccer players (12-15 years). Body size, bone age, motor performance tests, soccer-specific skill tests, and frequency of technical actions in SSG were analyzed. Statistic cluster-derived ANOVA F was used to identify which variables related to technical action most contributed to classifying subjects with similar performance. Discriminant analysis (Stepwise Method) was used to verify which predictor variables discriminated players into groups of low- and high-frequency technical actions in SSG. Statistical significance was set at 5%. Results: The group of high technical efficiency presented better performance in motor tests, shuttle run (P = 0.04; ES = −0.55), jumping laterally (P = 0.02; ES = 0.58), kicking speed (P = 0.03; ES = 0.60), soccer-specific skill tests, leading the ball in a straight line (LBSL) (P = 0.01; ES = −0.75), and zig-zag ball control (ZZBC) (P = 0.04; ES = −0.55); variable leading the ball in a straight line correctly discriminated 60% of players into high- and low-frequency groups. Conclusion: The frequency of technical actions in SSG was poorly influenced by motor performance and specific skill tests, and only the LBSL test correctly classified players of different frequencies of technical actions in SSG.

RESUMO O objetivo do presente estudo foi avaliar o efeito relativo da idade (ERI) nas seleções Brasileira de handebol que competiram nos campeonatos mundiais das categorias Sub-19, Sub-21 e Adulta. A amostra foi composta por 160 jogadores de handebol do sexo masculino, sendo 47 pertencentes a categoria Sub-19, 48 a Sub-21 e 65 a Adulta. A idade cronológica, massa corporal, estatura e posição de jogo de cada atleta foram obtidas no site oficial da Federação Internacional de Handebol. O nível de significância adotado foi de 5%. ERI foi observado em todas as três seguintes categorias Sub-19 (X2=21.511, P<0.01), Sub-21 (X2=15.894, P=0.01) e adulta (X2=35.123, P<0.01). Além disso, não foi encontrado ERI no processo de re-seleção pela categoria sequencial (P= 0.63, Sub-19 para Sub-21; P=0.46, Sub-21 para Adulta). O ERI foi encontrado nas seleções brasileiras de handebol. Contudo, este efeito não foi encontrado no processo de re-seleção, assim, os jogadores sofrem grande influência do ERI na categoria Sub-19 e isto permanece durante as categorias subsequentes até a equipe adulta.

ABSTRACT The aim of this study was to evaluate the relative age effect (RAE) in Brazilian male handball teams who competed in the world championships in the U-19, U-21, and adult categories. The sample was composed by 160 male handball players, 47 players being on U-19 category, 48 on U-21, and 65 on Adult category. The chronological age, body mass, height, and game position of each athlete were obtained on the International Federation of Handball website. The adopted significance level was of 5%. RAE was observed in all the three following categories U-19 (X2=21.511, P<0.01), U-21 (X2=15.894, P=0.01) and Adults (X2=35.123, P<0.01). Moreover, no RAE was found in re-selection process by sequential category (P= 0.63, U-19 to U-21; P= 0.46, U-21 to Adult). The RAE is found in Brazilian male handball national teams. However, this effect was not found in re-selection process, thus, players have great influence of RAE in U-19 and this remains through subsequent categories.

Abstract Aims: This study aimed to measure light-intensity physical activity (LPA) patterns in adolescents according to weekdays and school period and investigated associations between LPA patterns and associated factors. Methods: This is a cross-sectional study with 388 students of both genders, selected from public schools from Londrina city, Parana state. LPA was measured using accelerometry for seven consecutive days and was analyzed by the time spent in very short (15 to 30 s), short (30 to 60 s), intermediate (1 to 3 min), and long bouts (≥ 3 min). Results: Approximately 22% of the total daily time was spent in LPA. The time in LPA accumulated in short or intermediate bouts was higher than the time accumulated in very short or long bouts (P < 0.05). Gender was associated with short (β= 2.180; 95% confidence interval [CI], 0.357 to 4.003) and intermediate bouts (β = 2.822; 95% CI, 0.681 to 4.964), girls presented higher daily time. Age was inversely associated with very short (β = −0.925; 95% CI, −1.676 to −0.175) and intermediate bouts (β = −1.985; 95% CI, −3.579 to −0.390). The total time in LPA and time accumulated in very short, short, and intermediate bouts was higher in the school period when compared to the non-school period (P < 0.05). Conclusion: It could be concluded that the LPA patterns are predominantly composed of time spent in bouts between 30 seconds and three minutes. Gender, age, and school period appear to influence the LPA pattern in adolescents.

RESUMO O objetivo foi verificar a relação entre a orientação esportiva e a idade esquelética em atletas de futebol de 12 a 15 anos. A amostra foi de 106 jovens futebolistas, do sexo masculino, e foram feitas medidas do tamanho corporal, idade esquelética e para avaliação do comportamento competitivo usou-se o Sport Orientation Questionnaire com as subescalas competir (TQ1), vencer (TQ2) e estabelecer metas (TQ3). A Ancova não verificou diferença significativa entre os diferentes grupos de maturidade (p> 0,05) com a orientação esportiva, já a correlação de Spearman observou uma relação negativa apenas no grupo de maturidade “no tempo”, com o TQ2 (r=-0,28). Conclui-se que a maturação esquelética apresentou fraca relação com o comportamento dos jovens atletas de futebol.

ABSTRACT The objective was to verify the relationship between sportsmanship and skeletal age in soccer players aged 12 to 15 years. The sample was of 106 young male soccer players, and measurements of body size, skeletal age and competitive behavior were used. The Sport Orientation Questionnaire was used with the sub scales to compete (TQ1), to win (TQ2) and to establish goals (TQ3). The ANCOVA did not find a significant difference between the different maturity groups (P> 0.05) with the sports orientation, whereas the Spearman correlation observed a negative relation only in the maturity group “in time”, with TQ2 (r=- 0.28). It was concluded that the skeletal maturation presented a weak relation with the behavior of the young soccer athletes.

RESUMEN El objetivo fue comprobar la relación entre la orientación deportiva y la edad esquelética en futbolistas de 12 a 15 años. La muestra estaba compuesta por 106 jóvenes futbolistas de sexo masculino y se tomaron medidas del tamaño corporal y la edad esquelética, y para la evaluación del comportamiento competitivo se utilizó el Sport Orientation Questionnaire con las subescalas competir (TQ1), ganar (TQ2) y establecer metas (TQ3). El ANCOVA no verificó ninguna diferencia considerable entre los diferentes grupos de madurez (p> 0,05) respecto a la orientación deportiva, mientras que la correlación de Spearman observó una relación negativa solo en el grupo de madurez «en el tiempo» con el TQ2 (r=-0,28). Se concluye que la maduración esquelética presentó una débil relación con el comportamiento de los jóvenes futbolistas.

RESUMO Objetivo: Revisar sistematicamente a literatura para verificar a relação entre indicadores da aptidão neuromuscular na infância/adolescência e variáveis de resistência óssea na idade adulta. Fonte de dados: Revisão sistemática com pesquisa de artigos conduzida no PUBMED, SCOPUS, SPORTDiscus, Web of Science, PsycINFO, LILACS and SciELO, abrangendo todo o período da base até março de 2019. Síntese dos dados: A busca identificou 1.149 estudos, após análise de duplicidade e dos critérios de elegibilidade, quatro estudos foram relatados. Em um dos estudos, o baseline foi a infância e, nos demais, a adolescência. Na infância, ao ajustar o modelo por idade e índice de massa corporal, foi encontrada relação estatisticamente significativa para as meninas: salto em distância com índice quantitativo de ultrassom (β=0,11; p<0,05) e com velocidade do som (β=0,14; p<0,01). Entretanto, ao se fazer o controle do desempenho muscular na idade adulta, a relação deixou de ser significativa. Na adolescência, coeficientes variaram de 0,16 para bateria neuromotora e densidade mineral óssea (DMO) lombar a 0,38 para o teste de elevação de pernas em suspensão e a DMO dos braços. Variação explicada entre 2% (suspensão na barra e DMO do corpo total) e 12% (elevação de pernas em suspensão e DMO dos braços), portanto, melhor desempenho na aptidão neuromuscular na adolescência, mais resistência óssea na idade adulta. Conclusões: Em adultos, variáveis de resistência óssea apresentaram correlação significativa em magnitude baixa a moderada com indicadores da aptidão neuromuscular na adolescência, mas não na infância, após controlar pelo desempenho adulto na aptidão neuromuscular. No entanto, existe evidência limitada para apoiar a aptidão neuromuscular na juventude como fator determinante da resistência óssea na fase adulta.

ABSTRACT Objective: To systematically review the literature to verify the relationship between neuromuscular fitness indicators in childhood/adolescence and bone strength variables in adulthood. Data sources: A systematic review was conducted in PUBMED, SCOPUS, SPORTDiscus, Web of Science, PsycINFO, LILACS, and SciELO, covering the entire period until March 2019. Data synthesis: The search identified 1149 studies. After duplicity analysis and eligibility criteria, four studies were reported. In one study, baseline was childhood and, in the others, adolescence. In childhood, when adjusting the model for age and body mass index, a statistically significant relation was found for girls: standing long jump with quantitative ultrasound index (β=0.11; p<0.05) and with speed of sound (β=0.14; p<0.01). However, when controlling muscular performance in adulthood, the relationship was no longer significant. In adolescence, coefficients ranged from 0.16 for neuromotor battery and bone mineral density (BMD) in the lumbar region to 0.38 for hanging leg lift test and BMD of arms. The explained variance varied between 2% (bent arm hang for BMD total) and 12% (hanging leg-lift for BMD arms), therefore, a higher performance in neuromuscular fitness in adolescence was associated with better bone strength in adulthood. Conclusions: In adults, bone strength variables showed significant correlation from low to moderate magnitude with neuromuscular fitness indicators in adolescence, but not in childhood, after controlling for adult performance in neuromuscular fitness. However, there is limited evidence to support the neuromuscular fitness in early life as a determinant of bone strength in adulthood.

RESUMO Objetivo: Avaliar o tracking da aptidão cardiorrespiratória da infância à adolescência, bem como testar a via de moderação pela maturação somática. Métodos: A amostra foi composta de 375 crianças (197 meninos), com idades entre 7 e 10 anos na linha de base. Os sujeitos foram acompanhados por três anos. Massa corporal e estatura foram mensuradas como indicadores antropométricos e usadas para estimar a maturação somática pelo método de Moore. Aptidão cardiorrespiratória foi avaliada pelo teste de 9 minutos de corrida. Adiposidade corporal foi estimada pelo método de dobras subcutâneas, com medidas das dobras tricipital e subescapular, além de ter sido utilizada como covariável. A amostra foi categorizada em tercis, e então o coeficiente Kappa (k) e o coeficiente de correlação de concordância de Lin (LCCC) foram adotados para verificar estabilidade. Foram criadas variáveis dummy nas regressões para estimar o efeito de moderação. Todas as análises foram conduzidas no Stata 14.0, adotando p<0,05. Resultados: A aptidão cardiorrespiratória apresentou tracking baixo a moderado da infância para a adolescência (k=0,294; LCCC=0,458). Além disso, o status de maturação moderou significativamente a associação entre aptidão cardiorrespiratória na infância e adolescência (independentemente da coorte e adiposidade) em meninos (β=0,644; p<0,003) e na amostra total (β=0,184; p<0,020), mas não em meninas (-0,217; p=0,413). Conclusões: O tracking da aptidão cardiorrespiratória da infância à adolescência é baixo a moderado em ambos os sexos. Ainda, o estado maturacional moderou a associação entre aptidão cardiorrespiratória na infância e adolescência. Menor idade do pico de velocidade de crescimento foi associada à maior aptidão cardiorrespiratória.

ABSTRACT Objective: To evaluate cardiorespiratory fitness’ tracking from childhood to adolescence, as well as to test the moderation role of somatic maturation. Methods: Our sample was composed by 375 children (197 boys), with a baseline age between 7 and 10 years old. The children were followed-up over three years. Body mass and stature were measured as anthropometric indicators and were used to estimate maturity status through Moore’s method. Cardiorespiratory fitness was evaluated through 9-minute running test. Body adiposity was estimated through the subcutaneous skinfold method, with measures of triceps and subscapular skinfolds and used as a covariate. Sample was categorized into tertiles. Thereafter, the Kappa (k) coefficient and Lin’s concordance correlation coefficient (LCCC) tests were adopted to verify stability. Dummy variable in regression was used to test moderation effects. All analyses were conducted in Stata 14.0, adopting p<0.05. Results: Cardiorespiratory fitness presented a moderate to low tracking from childhood to adolescence (k=0.294; LCCC=0.458). Moreover, maturity status significantly moderated the association between cardiorespiratory fitness at childhood and adolescence (regardless of cohort and body adiposity) among boys (β=0.644; p=0.003) and role sample (β=0.184; p=0.020), but not girls (-0.217; p=0.413). Conclusions: Tracking of cardiorespiratory fitness from childhood to adolescence is moderate to low in both sexes. Moreover, maturity status moderated the relationship between cardiorespiratory fitness at baseline and in adolescence. A lower age at peak height velocity was associated to a greater cardiorespiratory fitness.

ABSTRACT BACKGROUND: Although the benefits of physical activity are clear, adherence to physical activity programs is a challenge, especially during transitional phases of life. OBJECTIVE: We aimed to identify adolescents who were more likely to drop out from physical activity and sports participation, from childhood to adolescence. DESIGN AND SETTING: This was a cross-sectional study on retrospective data regarding childhood activity among 803 Brazilian adolescents. The study was conducted at public schools in Londrina, Paraná, in 2011. METHODS: Habitual physical activity, sports participation during childhood, parental physical activity, socioeconomic status and perception of social relationships were self-reported. Cardiorespiratory fitness was estimated via a 20-m shuttle-run test and somatic maturation was estimated from the age at peak height velocity. RESULTS: Our results provided evidence that girls (physical activity: odds ratio, OR: 4.37 [95% confidence interval, CI: 1.86-10.3]; sports: OR: 2.65 [95% CI: 1.39-5.05]) and adolescents with low cardiorespiratory fitness (physical activity: OR: 1.77 [95% CI: 1.13-2.78]; sports: OR: 1.62 [95% CI: 1.15-2.26]) were more likely to drop out from active behaviors. Children with inactive mothers and inactive fathers (OR: 3.55 [95% CI: 1.12-11.3]) also showed a higher dropout rate from physical activity. Adolescents with negative perceptions of friendships (OR: 2.33 [95% CI: 1.21-4.47]) were more likely to drop out from sports. CONCLUSIONS: Higher dropout rates from active lifestyles during childhood were observed among girls and adolescents with low cardiorespiratory fitness. Parental inactivity and negative perceptions of friendships were also potential risk factors for discontinuation of childhood physical activity and sports.