Factors related to lower limb performance in children and adolescents aged 7 to 17 years: A systematic review with meta-analysis.

BACKGROUND: The literature identifies several factors that are associated with lower limb performance (LLP). However, there is little consensus on which factors have the major associations with LLP. OBJECTIVE: Examine, analyze and summarize the scientific evidence on the factors associated with the performance of LLP in children and adolescents of both sexes aged between 7 and 17 years. DESIGN: This systematic review was conducted following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement and was registered in PROSPERO. DATA SOURCES: A systematic literature search of five electronic databases (i.e., SPORTDiscus, PubMed, CINAHL, Google Scholar, and SCOPUS) with date restrictions was conducted (2010 to 2021). ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Eligibility criteria included (i) a study published between 2010 and 2021; (ii) a research study with observational design; (iii) a study analyzing LLP; and (iv) a sample composed of young people between 7 and 17 years old (regardless of sex). ANALYSES: Literature analysis was carried out in English and Portuguese between 2018 and 2021, "blindly" by two researchers. For data sorting, Rayyan® was used. Data extraction and evidence analysis were performed "blindly", using the Loney scale. The minimum items for observational studies were analyzed by the STROBE checklist. Meta-analyses were conducted based on age group (Childhood [7 to 11 Yrs] and Adolescence [12 to 17 Yrs]) and puberty stages (i.e., Prepupertal and Pubertal). The heterogeneity between the samples of the studies was assessed using the "Cochran's Q" and "I^2" statistics. Meta-regression analyses were performed to check the factors related to heterogeneity of the studies and to check the associations between chronological age and LLP. RESULTS: The literature search resulted in 1,109,650 observational studies of which 39 were included in this review. Through Meta-analysis and Meta-regressions, it was possible to indicate that advancing chronological age related to increased LLP (p<0.01), and that in relation to puberty stages pubertal subjects had higher LLP than their pre-pubertal peers (p<0.01). DISCUSSION: The main findings of the present systematic review suggest that as chronological age advances (childhood to adolescence), neuromuscular systems mature and this may be due to advancing puberty, which is also associated with an increase in LLP. CONCLUSION: The factors associated with lower limbs performance are still inconsistent in the literature. However, advancing chronological age and stage of puberty are both associated with increased lower limbs performance. TRIAL REGISTRATION: ID-PROSPERO-CRD42020137925.

Relationship of Biological Maturation with Muscle Power in Young Female Athletes.

There is still no consensus on how biological maturation (BM) affects the muscle power of upper and lower limbs in young people. The objective was to verify associations between BM and muscle power, as well as to compare the muscle power of upper (ULP) and lower limbs (LLP) among young athletes in different stages of BM. The sample consisted of 79 female athletes (10.9 ± 1.11 years old). Regarding BM, the sample was divided into three groups: delayed BM, synchronized BM, and accelerated BM. BM was identified by subtracting chronological age from bone age (BA). BA was measured by a mathematical model based on anthropometry. The muscular power of the upper limbs was analyzed by the medicine ball launch test, and that of the lower limbs was analyzed by the countermovement jump on a force platform. BM and BA correlated with ULP (BA: r =0.74; BM: r =0.65) and LLP (BA: r = 0.50; BM: r =0.41). In the comparisons of the tests of ULP and LLP, the groups with synchronized and accelerated BM were superior to the group with delayed BM. The advance of BM is associated with the ULP and LLP, as well as the advance of the BM affects muscle power in young female athletes. This occurs due to the increase in body mass resulting from the advancement of BM, which may favor the predominance of lean body mass, assisting in the production of muscle strength.

Can the Neuromuscular Performance of Young Athletes Be Influenced by Hormone Levels and Different Stages of Puberty?

BACKGROUND: Endocrine mechanisms can be a determining factor in the neuromuscular performance of young athletes. OBJECTIVE: The objective of the present study was to relate maturational and hormonal markers to neuromuscular performance, as well as to verify whether young athletes with different testosterone levels show differences in muscle strength. METHODS: The sample consisted of 37 young male Brazilian athletes (11.3 ± 0.94 years) who were members of a sports initiation project. Hormonal markers were analyzed biochemically by blood samples, and maturation markers by mathematical models based on anthropometry. Body composition was verified by tetrapolar bioimpedance. The performance of upper and lower limb strength and body speed were analyzed. RESULTS: Hormonal and maturational markers were related to neuromuscular performance (p < 0.05). Young people with higher testosterone levels showed higher muscle strength (p < 0.05). Artificial neural networks showed that testosterone predicted the performance of upper limbs by 49%, and maturation by 60%. Maturation foreshadowed the performance of lower limbs by 30.3%. CONCLUSION: Biological maturation and hormonal levels can be related to neuromuscular performance, and young people with higher testosterone levels show superior muscle strength in relation to the others.

Biological Maturation and Hormonal Markers, Relationship to Neuromotor Performance in Female Children.

Background: Mechanisms that influence muscle strength can interfere with neuromotor performance and overall health, thus hormone markers and maturation can interact in this process. Objective: The present study aimed to verify the relationship of hormonal markers and biological maturation on neuromotor abilities in young people. Methods: This is a cross-sectional study with 44 female participants (11.5 ± 1.5 years). Hormones were analyzed biochemically. Skeletal and somatic maturation were analyzed using anthropometry. The muscular power of the upper and lower limbs, body speed with change of direction, and speed of the upper limbs were verified. Results: Bone age was correlated with hormonal markers (estradiol: r = 0.58; p = 0.0007), (testosterone: r = 0.51; p = 0.005). Peak growth velocity correlated with estradiol (r = 0.51; p = 0.004). The power of the lower limbs (estradiol: r = 0.52; p = 0.006; testosterone: r = 0.42; p = 0.03) and of the upper limbs (estradiol: r = 0.51; p = 0.007; testosterone: r = 0.42; p = 0.02) had a positive correlation with hormone levels and had similar results with maturation. The analysis by artificial neural networks indicated that the maturation can predict the neuromotor performance between 57.4% and 76%, while the hormonal markers showed a potential of more than 95% for the foreshadowing of the neuromotor performance of the upper limbs. Conclusion: It was possible to conclude that the hormones had a relationship with maturational development and bone age in female subjects.

Level of physical activity and motor coordination of schoolchildren in different maturational stages / Nível de atividade física e coordenação motora de escolares em diferentes estágios maturacionais

INTRODUCTION: Studies and debates in the field of motor development reveal that sport and physical activity develop and improve motor skills. These studies seek to understand the changes that occur with movement, which becomes more complex as it develops through physical activity. OBJECTIVE: To compare the level of physical activity and motor coordination of students in different maturational stages and to relate the level of physical activity with the motor coordination of young people. METHODS: Descriptive research with cross section. The study included 46 male individuals, aged between 10 and 14 years. The Baecke Habitual Physical Activity questionnaire was applied; the maturity stage was verified through the Pubertal Maturation Prediction Equation; body composition was assessed using the Guedes protocol for children and adolescents; Finally, the coordinating performance was rated using the Korperkoordinationstest fur Kinder (KTK) test battery. RESULTS: There were significant differences for the variables Age and Height between all stages: P3, P4 and P5 of maturation. The differences found in body mass occurred only between stages P3 and P5; P4 and P5. It was also observed that no significant differences were found for motor coordination between the maturation stages. The same occurred when the physical activity indices were compared CONCLUSION: There is no difference in the level of physical activity between stages 3, 4 and 5 of sexual maturation, nor does the maturational stage seem to influence the level of motor coordination of young schoolchildren.

INTRODUÇÃO: Estudos e debates na área do desenvolvimento motor revelam que o esporte e a atividade física desenvolvem e melhoram as habilidades motoras. Esses estudos buscam compreender as mudanças que ocorrem com o movimento, o qual se torna mais complexo à medida que se desenvolve através da atividade física. OBJETIVO: Comparar o nível de atividade física e coordenação motora de escolares em diferentes estágios maturacionais e relacionar o nível de atividade física com a coordenação motora de jovens MÉTODO: Pesquisa descritiva com corte transversal. Participaram do estudo 46 indivíduos do sexo masculino, com idades entre 10 e 14 anos. Foi aplicado o questionário de Atividade Física Habitual de Baecke; o estágio de maturidade foi verificado através da Equação de Predição da Maturação Puberal; a composição corporal foi avaliada através do protocolo de Guedes para crianças e adolescentes; por fim, o desempenho coordenativo foi classificado por meio da bateria de testes Korperkoordinationstest fur Kinder (KTK). RESULTADOS: Houve diferenças significativas para as variáveis Idade e Estatura entre todos os estágios: P3, P4 e P5 de maturação. As diferenças encontradas na massa corporal ocorreram apenas entre os estágios P3 e P5; P4 e P5. Observou-se também que não foram encontradas diferenças significativas para a coordenação motora entre os estágios de maturação. O mesmo ocorreu quando os índices de atividade física foram comparados. CONCLUSÃO: Não existe diferença no nível de atividade física entre os estágios 3, 4 e 5 da maturação sexual, assim como o estágio maturacional não parece influenciar o nível de coordenação motora de jovens escolares

Estágios maturacionais: comparação de indicadores de crescimento e capacidade física em adolescentes / Maturational stages: comparison of growth and physical capacity indicators in adolescents

INTRODUCTION: The identification of physical capacity is an important marker related to healthy behavior during childhood and adolescence, in which some factors appear to contribute to motor performance such as maturation and hormonal levels. OBJECTIVE: To compare growth indicators, physical capacity and hormonal markers according to gender and maturational stage in adolescents. METHODS: Eighty-nine adolescents of both genders aged 10-13 years participated in the study. Sexual maturation was evaluated using the Tanner's self-evaluation method. Physical capacity (explosive strength of upper and lower limbs, upper limb velocity and agility) and hormonal markers (testosterone and estradiol) were evaluated through the chemiluminescence method. RESULTS: In the comparison by gender, girls had higher weight (p = 0.023), height (p = 0.018) and fat percentage values (p = 0.001), while boys presented better motor performance for the explosive strength of upper limbs (p = 0.005) and lower limbs (p = 0.011), agility (0.018) and upper limb velocity (p = 0.014). Regarding maturational stage, boys did not present differences in any variable analyzed; (Stage V versus I), height (stage III, IV and V versus I) and upper limb explosive strength (stage III and IV versus I). CONCLUSION: Growth, weight and height, as well as explosive strength of upper limbs were higher in girls at more advanced maturational stages and appear to be gender dependent.

INTRODUÇÃO: A identificação da capacidade física se apresenta como importante marcador relacionado ao comportamento saudável durante a infância e adolescência, no qual alguns fatores aparentam contribuir para o desempenho motor como a maturação e níveis hormonais. OBJETIVO: Comparar indicadores de crescimento, capacidades físicas e marcadores hormonais de acordo com o sexo e estágio maturacional em adolescentes. MÉTODO: Participaram do estudo 89 adolescentes de ambos os sexos de 10 a 13 anos. Foram avaliados a maturação sexual, obtida através do método de autoavaliação de Tanner, capacidades físicas (força explosiva de membros superiores e inferiores, velocidade de membros superiores e agilidade) e marcadores hormonais (testosterona e estradiol) através do método de quimiluminescência. RESULTADOS: Na comparação pelo sexo, as meninas obtiveram maiores valores para o peso (p=0,023), estatura (p=0,018) e percentual de gordura (p=0,001), enquanto que os meninos apresentaram melhor rendimento motor para a força explosiva de membros superiores (p=0,005) e inferiores (p=0,011), agilidade (0,018) e velocidade de membros superiores (p=0,014). Em relação ao estágio maturacional os meninos não apresentaram diferenças em nenhuma variável analisada; enquanto as meninas em estágio maturacional mais avançado apresentaram maiores valores para o peso (estágio V versus I), estatura (estágio III, IV e V versus I) e força explosiva de membros superiores (estágio III e IV versus I). CONCLUSÃO: Os indicadores de crescimento, peso e estatura, bem como a força explosiva de membros superiores foram mais elevados nas meninas em estágios maturacionais mais avançados e parecem ser dependentes do sexo.

Relação da idade óssea e marcadores hormonais com a capacidade física de adolescentes / Relationship between skeletal age, hormonal markers and physical capacity in adolescents

INTRODUCTION: Physical capabilities are an important parameter of the functional development of adolescents, not only by chronological age but also by their maturational state, as individuals with the same chronological age can have different performance to their less mature counterparts. OBJECTIVE: To compare and relate the physical capabilities and hormonal markers according to sex and maturity of adolescents. METHODS: The sample consisted of adolescents of both sexes, aged 10 to 14 years. We evaluated the maturity achieved by a predictive equation of skeletal age, physical capabilities (explosive power of upper and lower limbs, velocity of upper limbs and agility) and hormonal markers (testosterone and oestradiol) via chemiluminescence. RESULTS: Females showed more advanced maturational status, higher weight, body height and oestradiol levels; males performed better in the explosive force of upper and lower limbs, upper limb speed, agility and testosterone levels. In the normal maturational state males showed greater skeletal age, body weight, body height, explosive strength of upper and lower limbs, and testosterone levels; the females in the normal maturational state had higher skeletal age, body weight, body height, explosive upper limb strength and oestradiol levels. In the male correlation analysis, skeletal age was related to the explosive strength of upper and lower limbs and testosterone; while skeletal age in females was related to explosive upper limb strength and oestradiol. CONCLUSION: It is concluded that maturation, testosterone and oestradiol levels play an important role in the physical aspects and performance of motor skills of adolescents, especially in upper limb force which was more related to the maturation obtained by skeletal age of males and females.

INTRODUÇÃO: A capacidade física é um importante parâmetro do desenvolvimento funcional a ser investigado em crianças e adolescentes, não apenas pela idade cronológica e sim pelo seu estado maturacional, já que sujeitos com mesma idade cronológica podem apresentar desempenho diferente ao seu par menos maturado. OBJETIVO: Comparar e relacionar as capacidades físicas e marcadores hormonais de acordo com o sexo e maturação de crianças e adolescentes. MÉTODO: A amostra foi composta por 89 crianças e adolescentes de ambos os sexos de 10 a 13 anos. Foram avaliados a maturação obtida através de uma equação preditora da idade óssea, capacidades físicas (força explosiva de membros superiores e inferiores, velocidade de membros superiores e agilidade) e marcadores hormonais (testosterona e estradiol) através do método de quimioluminescência RESULTADOS: Na comparação entre os sexos as meninas obtiveram estado maturacional mais avançado, maior peso, estatura corporal e níveis de estradiol; já os meninos apresentaram melhor desempenho na força explosiva de membros superior e inferior, velocidade de membro superior, agilidade e níveis de testosterona. Relativo à maturação, os meninos em estado maturacional normal apresentaram maior idade óssea, peso e estatura corporal, força explosiva de membros superior e inferior, e níveis de testosterona; já as meninas no estado maturacional normal obtiveram maior idade óssea, peso, estatura corporal, força explosiva de membro superior e níveis de estradiol. Na análise de correlação dos meninos a idade óssea se relacionou com a força explosiva de membros superior e inferior e testosterona; já a idade óssea das meninas se relacionou com a força explosiva de membro superior e estradiol. CONCLUSÃO: Desta forma, se conclui que maturação e os níveis de testosterona e estradiol exercem um importante papel nos aspectos físicos e no desempenho das habilidades motoras das crianças e dos adolescentes, principalmente na força de membro superior a qual se mostrou mais relacionada com a maturação obtida pela idade óssea de meninos e meninas.

Relação da idade óssea com antropometria e aptidão física em jovens praticantes de voleibol / Relationship of age with bone and fitness anthropometry practitioners in youth volleyball / Relación de edad ósea con antropometría y condición física en jugadores jóvenes de vóleibol

Resumo O estudo teve como objetivo correlacionar a idade óssea, os componentes antropométricos e a aptidão física em 149 crianças de 8 a 14 anos. Foram aferidos estatura, massa corporal, perímetros de braço e de perna, perímetros de braço e de perna corrigidos, diâmetros bicristailíaco e biacromial, dobras cutâneas tricipital e perna, teste motores de agilidade, velocidade de membros superiores e força explosiva de membros inferiores e superiores e o exame de raios X de mão e punho para verificar maturação. Nos resultados, encontramos correlação positiva entre a idade óssea e as demais variáveis, com exceção das dobras cutâneas tricipital, de perna e teste de agilidade. Dessa forma, verificamos a influência da maturação sobre componentes antropométricos e motores. Assim, possibilitamos uma melhor forma de controle dos processos de detecção, seleção e orientação esportiva.

Abstract The study aimed to correlate bone age, anthropometric measurements and physical fitness in 149 young volleyball players between ages 8 and 14. Height, weight, arm and leg circumferences, adjusted arm and leg circumferences, bi-iliac and biacromial breadths, tricipital and leg skin fold thicknesses, physical fitness tests, coordination and explosive strength of the upper and lower limbs were measured, in addition to x-rays of hand and wrist to check for maturation. Results showed positive correlation between bone age and all other variables, except tricipital skinfold, leg skinfold and agility. We concluded that maturation has influence on anthropometric and motor components, leading to a better control in the process of selecting and promoting young athletes.

Resumen El estudio tuvo como objetivo observar la correlación entre edad ósea, variables antropométricas y condición física en 149 niños de 8 a 14 años. Se midieron la estatura, la masa corporal, la circunferencia del brazo y de la pierna, la circunferencia corregida del brazo y de la pierna, el diámetro bi-cresta ilíaca y biacromial, y el pliegue cutáneo del tríceps. Se hicieron pruebas motoras de agilidad de las piernas, de velocidad de los miembros superiores y de fuerza explosiva de los miembros superiores e inferiores, y se hicieron radiografías de la mano y el puño para verificar la maduración. En los resultados se encontró una correlación positiva entre la edad ósea y otras variables, con la excepción del pliegue cutáneo del tríceps y la prueba de agilidad de las piernas. Por tanto, se observa la influencia de la maduración de las variables antropométricas y motoras, lo que permite una mejor manera de controlar los procesos de detección, selección y orientación deportiva.