Relationship between strength and flexibility levels in young soccer players / Relación entre los niveles de fuerza y flexibilidad en jóvenes jugadores de fútbol

INTRODUCTION: Balance of strength and flexibility between the dominant (DL) and non-dominant limbs (NDL) in young soccer players is essential, since it can minimize the possible injury-triggering mechanisms and their negative influence on performance. The aim of this study was to evaluate and compare the unilateral and bilateral strength and flexibility between the DL and NDL in young soccer players. MATERIAL AND METHODS: The sample consisted of 30 individuals (aged 15.97 ± 0.67 years). The isokinetic strength was measured at the velocities of 60°s and 180°s in the concentric action of the quadriceps and hamstrings as well as eccentric of the hamstrings, and in the conventional and functional ratios, along with hip flexion range of motion. RESULTS: The results showed the athletes had an eccentric strength of the hamstrings at 60°s in the DL significantly (p < 0.05) stronger than in the NDL, and the DL had a significant H/Q ratio (p < 0.05) more balanced than the NDL. CONCLUSIONS: Young soccer athletes may present a non-standard isokinetic results. These results are observed because of the difference in muscle strength of the posterior thigh compared to DL and NDL and the balance relation between the quadriceps and the hamstrings, generating an asymmetry of strength between the limbs and on the same member. It is necessary to monitor and devise training strategies to avoid these imbalances in order to prevent injuries

INTRODUCCIÓN: El equilibrio de la fuerza y de la flexibilidad entre las piernas dominantes (PD) y no dominantes (PND) en jóvenes jugadores de fútbol es imprescindible, pues puede minimizar los posibles mecanismos desencadenantes de lesiones y su influencia negativa en el desempeño. El objetivo de este estudio fue evaluar y comparar la fuerza y la flexibilidad uni y bilateral entre las PD y PND en jóvenes jugadores de fútbol. MATERIAL Y MÉTODOS: La muestra fue compuesta por 30 individuos (con edad entre 15,97 ± 0,67 años). Se evaluó la fuerza isocinética a las velocidades de 60°/s y 180°/s en la acción concéntrica del cuádriceps e isquiotibiales y excéntrica de los isquiotibiales, y en las razones convencional y funcional, además de la goniometría para la flexión de cadera. RESULTADOS: Los resultados demostraron que los atletas poseían una acción excéntrica de los isquiotibiales en 60°/s en las PD significativamente (p < 0,05) más fuerte que en las PND, además de las PD tener una relación I/Q significativamente (p < 0,05) más equilibrada que las PND. CONCLUSIONES: Los atletas jóvenes de fútbol pueden presentar resultados isocinéticos no estandarizados. Estos resultados se observan debido a la diferencia en la fuerza muscular del muslo posterior con relación a las PD y PND y la relación de equilibrio entre el cuádriceps y los isquiotibiales, generando una asimetría de fuerza entre los miembros y en el mismo miembro. Es necesario monitorear y elaborar estrategias de entrenamiento para evitar estos desequilibrios, a fin de evitar lesiones

Effects of Strength Training Program and Infrared Thermography in Soccer Athletes Injuries.

The purpose of this investigation was to examine the effects of a periodized strength training program and the use of infrared thermography (IRT) in injuries mapping in under 20-year-old (U-20) soccer players. In this study, 26 professional soccer players participated in strength training (ST) twice a week and were tested with IRT consistently across the 1-year. Strength, vertical jump, heat differences and injuries were tracked and analyzed. Results: 69 injuries occurred during 12 months of tracking; most identified injuries were: contusions, sprains, strains to the thigh (n = 16), ankle (n = 15) and knee (n = 12). Differences (>7 °C) in IRT patterns were noted among injured and non-injured athletes. Significant improvements in strength (p < 0.005) were found for vertical jump, bench press, front lat pull down, shoulder press, leg press, leg curl and squat. Number of injuries decreased from 23 (33.3%) to 14 (20.3%) when early year rates were compared to late year (p < 0.005). Combined ST and IRT represent useful strategies for reducing injuries among U-20 soccer players.

Occurrence and type of sports injuries in elite young Brazilian soccer players / Ocurrencia y el tipo de lesiones deportivas en los jóvenes jugadores de fútbol brasileños de élite

Introduction: The aim of this study was to analyze the injuries affected in young soccer athletes of high performance categories, under (U) -11, U-13, U-15, U-17 and U-20 years and the associations between the variables related the injuries. Material and method: Data were collected from medical records of the medical department of 143 injured athletes belonging to a club in the first division of the Brazilian Championship. The young athletes were evaluated in the following categories: under (U) -11, n = 30 (10.45 ± 0.5 years), U-13, n = 34 (12.15 ± 0.3 years) U-15, n = 23 (14.56 ± 0.4 years), U-17, n = 24 (16.52 ± 0.5 years), U-20, n = 32 (18.24 ± 0.6 years). Data collection was conducted from January 2014 to November 2014 (11 months). The data were analyzed and classified according to the categories and the lesions identified as per the recommendations of the study group in injury FIFA Medical Assessment and Research Centre. Results: The results showed that there was a total of 200 lesions in all categories, the teams U-15, U-17, U-20 stood out with the greatest occurrences of injuries (p<0.05) and index of injuries (p<0.05). The Pearson correlation test showed a positive and significant coefficient of correlation (r = 0.879; p < 0.05) between index of injuries and hours of game. Conclusions:It was observed that the occurrence and characteristics of lesions of young soccer players in different categories are higher according to the increasing number of games and that the older groups demonstrate a greater number of lesions more similar to those in adults

Introducción: El objetivo del estudio fue analizar las lesiones en los jóvenes futbolistas en categorías de alto rendimiento barro (SUB) -11, SUB -13, SUB-15, SUB-17 and SUB-20 años y las asociaciones entre las variables relacionadas con las lesiones. Material y métodos: Se recogieron datos de los registros médicos del departamento médico de 143 jóvenes futbolistas pertenecientes a un club de la primera división del Campeonato Brasileño. Los jóvenes futbolistas fueron evaluados en las siguientes categorías: SUB -11, n = 30 (10,45 ± 0,5 años), SUB-13, n = 34 (12,15 ± 0,3 años), SUB-15, n = 23 (14,56 ± 0,4 años), SUB-17, n = 24 (16,52 ± 0,5 años) y SUB-20, n = 32 (18,24 ± 0,6 años). La recolección de datos se llevó a cabo a partir de enero 2014 a noviembre 2014 (11 meses). Los datos fueron analizados y clasificados por las categorías y las lesiones identificadas de acuerdo con las recomendaciones del grupo de estudio en la lesión de Evaluación Médica de la FIFA y el Centro de Investigación. Resultados: Los resultados mostraron que hubo un total de 200 lesiones en todas las categorías. Los equipos B-15, B-17 y B-20 se destacaron con las mayores ocurrencias de lesiones (p<0,05) y el índice de lesiones (p<0,05). La prueba de correlación de Pearson mostró un coeficiente de correlación positivo y significativo (r = 0,879; p <0,05) entre el índice de lesiones y horas de juego. Conclusiones: Se observó que la incidencia y características de las lesiones de los jóvenes futbolistas en diferentes categorías son más altos de acuerdo con el aumento del número de juegos y que los grupos de mayor edad demuestran un mayor número de lesiones más similares a las de los adultos

Low intensity static stretching does not modulate heart rate variability in trained men / Alongamento estático de baixa intensidade não modula a variabilidade da frequência cardíaca em homens treinados

OBJECTIVE: To investigate the acute effect of static stretching on heart rate variability in trained men. METHODS: Eight subjects were randomly submitted to two situations, as follows: a static stretch protocol and 20 minutes at rest. The stretch protocol consisted of two sets of 30 seconds of static stretch of the chest muscles with a 40 second of interval between them. After 48 hours, the procedures were reversed so that all the subjects should were submitted to the two situations. The values of heart rate variability were measured before and after the experimental and control situation (stretch vs. rest). We registered the following cardiac variables: root mean square of standard deviation (rMSSD), the number of pairs of successive beats that differ by more than 50 ms (pNN50), low frequency (LF) and high frequency (HF). The Shapiro-Wilk and the paired Student's test were used for statistical analysis; a critical level of significance of p < 0.05 was adopted. RESULTS: No significant differences (p > 0.05) were found (stretching vs. control) to the RMSSD, pNN50, LF and HF indices. However, although no statistical differences were observed, the figures show large changes on mean values, suggesting an unclear effect on the sympathetic-vagal modulation. CONCLUSION: The present results suggest that a low intensity (motion range until discomfort point) and volume (1 minute) of static stretching does not significantly affect the acute sympathetic-vagal control in trained men. Because the protocol did not show differences regarding the studied variables, we suggest that there is not a sufficient level of physiological basis to perform this type of exercise in a traditional pre-exercise setting, if the purpose is obtain gains in physical performance.

OBJETIVO: Nosso objetivo foi verificar o efeito agudo do alongamento estático sobre a variabilidade da frequência cardíaca (VFC) em homens treinados. MÉTODOS: Oito voluntários (n = 8) foram randomicamente submetidos a duas situações, a saber: alongamento estático (AE) ou 20 minutos em repouso (CTRL). O protocolo de alongamento consistiu em duas séries de 30 segundos para musculatura do peitoral (40 segundos de intervalo). Após 48 horas, os procedimentos foram realizados de maneira reversa, de forma que todos os participantes realizaram as duas situações (ALONGAMENTO e CRTL) ao final do estudo. Os valores de VFC foram medidos antes e imediatamente depois das situações experimental e controle (alongamento vs. repouso). Para registro das variáveis cardíacas coletadas (rMSSD, pNN50, LF e HF) no presente estudo, nós utilizamos um relógio Polar RS800CX (Polar Electro OY, Finland). As análises estatísticas realizadas foram feitas através da aplicação do teste de Shapiro-Wilk seguido pelo teste t de Student pareado, sendo adotado um nível crítico de significância de p < 0.05. RESULTADOS: Nenhuma diferença significativa (p > 0.05) foi observada (alongamento vs. controle) quando as variáveis foram analisadas. CONCLUSÃO: O presente estudo sugere que o alongamento estático com baixo volume de aplicação não altera significativamente o controle simpato-vagal em homens treinados. Na medida em que o protocolo utilizado não resultou em diferenças significativas nas variáveis estudadas, nós inferimos que não há fundamento fisiologicamente válido para a realização deste tipo de exercício em sua forma tradicional pré-exercício quando o objetivo for a obtenção de ganhos na performance física.

Perfil antropométrico, composición corporal y somatotipo de jóvenes futbolistas brasileños de diferentes categorías y posiciones / Perfil antropométrico, composição corporal e somatotipo de jovens atletas de futebol brasileiros de diferentes categorías e posições / Anthropometric profile, body composition and somatotype of brazilian youth soccer players of different categories and positions

El objetivo de este estudio es identificar y describir las medidas antropométricas, composición corporal y somatotipo de futbolistas brasileños en varias categorías y posiciones de accionamiento en el campo. La muestra de este estudio está conformada por un grupo de 1.115 jugadores de fútbol masculino y divididos en ocho grupos: Sub 07 (n=60); Sub 09 (n=75); Sub 11 (n=140); Sub 13 (n=182); Sub 15 (n=184); Sub 17 (n=166); Sub 20 (n=144) y Profesionales (n=164). Se utilizó una estadística descriptiva (media ± desviación estándar) a través del SSPS y utlilizando v21 "One-way ANOVA" complementando la prueba "Bonferroni" de significância, considerando um valor p<0,05. Las variables antropométricas relacionados con la composición corporal: peso corporal, altura, porcentaje de grasa corporal, SDC (suma de los pliegues cutáneos), mostraron la evolución perfecta entre las categorías analizadas, lo que significa que existe una armonía en el proceso de evolución entre los grupos.

Objetivo: identificar e descrever as medidas antropométricas, de composição corporal e do somatotipo de jogadores brasileiros em diversas categorias e posições no campo. Método: a amostra consistiu em 1.115 jogadores de futebol do sexo masculino e divididos em oito grupos: Under 07(n = 60); Sub-09 (n = 75); Sub 11 (n = 140); Sub 13 (n = 182); Sub 15 (n =184); Sub 17 (n = 166); Sub-20 (n = 144) e Professional (n = 164). Estatística descritiva (média ± desvio padrão) foi utilizada através do SPSS, utilizandov21 “one-way ANOVA”, complementar “Bonferroni” significado, um teste considerando o valor de p <0,05. Resultado: as variáveis antropométricas relacionadas à composição corporal: massa corporal, estatura, percentual de gordura corporal, SDC (somatório das dobras cutâneas) mostraram a evolução perfeita entre as categorias analisadas. Conclusão: há harmonia no processo de evolução entre grupos.

Objective: To identify and describe the anthropometric measurements,body composition and somatotype of Brazilian players in various categories and positions in the field. Method: The sample consisted of 1,115 malesoccer players and divided into eight groups: Under 07 (n = 60); Sub-09(n = 75); Sub 11 (n = 140); Sub 13 (n = 182); Sub 15 (n = 184); Under 17(n = 166); U-20 (n = 144) and Professional (n = 164). Descriptive statistics(mean ± standard deviation) was used through SPSS, using v21 “one-wayANOVA”, complementary “Bonferroni” significance test considering thevalue of p <0.05. Results: Anthropometric variables related to body composition:body weight, height, body fat percentage, SDC (sum of skin folds)showed the perfect evolution of the categories analyzed. Conclusion: thereis harmony in the evolution process between groups.

Análise dos aspectos antropométricos em jovens atletas de alto rendimento praticantes da modalidade futebol / Analysis of the anthropometric features in young athletes of high yield practitioners of the soccer modality

As medidas antropométricas estão sendo amplamente utilizadas, na verificação das adaptações em resposta ao treinamento, para acompanhamento e desenvolvimento na seleção de atletas. Este estudo teve como objetivo analisar e caracterizar a composição corporal de atletas da categoria de base de um clube de alto rendimento do Estado do Rio de Janeiro, na modalidade futebol participantes do período competitivo do ano de 2008. Todos os dados da amostra foram coletados no término da temporada em dezembro. A amostra desse estudo foi caracterizada por um grupo de 198 futebolistas do sexo masculino divididos em 5 grupos: Sub19 n=40, Sub17 n=42, Sub15 n=41, Sub13 n=35 e Sub11 n=40. Foi utilizada estatística descritiva (média ± desvio padrão) através do programa BioEstat 4.0 e utlilizou-se da “ANOVA one way” complementando-se com o teste “Bonferroni” com nível de significância para as amostras de P<0,01. As variáveis antropométricas ligadas à composição corporal: peso corporal, estatura, percentual de gordura, SDC (somatório de dobras cutâneas), peso gordo e peso magro mostraram perfeita evolução dentre as categorias analisadas, o que significa ter uma harmonia no processo de evolução entre os grupos. O fator que caracterizou o desenvolvimento desses atletas foi à diminuição da massa óssea (Relativo) provavelmente por causa do fim do desenvolvimento longitudinal e o aumento da massa muscular (Relativo e Absoluto) proveniente da necessidade imposta pela dinâmica do jogo ser mais competitiva na transição entre as categorias.

The anthropometric measures are being used, very broadly, in order to verify the adjustments in connection to the response of training, monitoring and development for the chose of athletes. The scope of this study was to analyze and characterize the body composition of athletes of a base category of a high yield Sport Club in the State of Rio de Janeiro, in the form of soccer player’s competitors regarding the period of the year 2008. All the taster data were collected at the end of the season in December. The test of this study was developed based on a group of 198 male soccer players divided into 5 groups: Under19 n=40, Under17 n=42, Under15 n=41, Under13 n=35 and Under11 n=40. It was used a descriptive statistic ( average ± standard ) by means of the BioEstat 4.0 Program and it was also used the “ANOVA one way” complementing the test “Bonferroni” with a significant level to the tests of P<0,01. The anthropometric variables related to the composition: body weight, height, body fat percentage, SDC (sum of skin folds), fat weight and thin body weight perfectly shows the evolution among the analyzed categories, which means having a line in the process of evolution of the groups. The factor that has characterized the development of these athletes was the reduction of the bone mass (Relative) probably caused by the end of the longitudinal development and the increased of muscle mass (Relative and Absolute) raised by the imposed dynamic of the game be more competitive in the transition of the categories.