The purpose of this study was to investigate the effect of different volumes of plyometric exercise (i.e., 100, 200, or 300 hurdle jumps) on acute strength and jump performance and on the acute hormonal and lactate responses in rugby players. Eleven young male elite rugby players (age, 23.5 ± 0.9 years; height, 173 ± 4.8 cm) volunteered for the study. Maximal isometric peak torque (PT), maximal rate of force development (RFD), squat jump (SJ), and drop jump (DJ) performance were assessed before and 5 minutes, 8 hours, and 24 hours after 100, 200, or 300 jumps. In addition, total testosterone (TT), cortisol (COR), and lactate were measured before and after the 3 different plyometric exercise volumes. There were significant decreases in the PT (p < 0.02) and maximal RFD (p < 0.001) 5 minutes, 8 hours, and 24 hours after 100, 200, and 300 jumps, with no differences between the exercise volumes. Additionally, there were significant decreases in the SJ (p < 0.001) and DJ (p < 0.01) performances 24 hours after 100, 200, and 300 jumps, with no differences between the exercise volumes. However, there were significant increases in the TT (p < 0.001), COR (p < 0.05), and lactate (p < 0.001) after 100, 200, and 300 jumps, with no differences between the exercise volumes. All plyometric exercise volumes (100, 200, and 300 jumps) resulted in similar neuromuscular, metabolic, and hormonal responses.
O objetivo deste estudo foi avaliar a força máxima dinâmica (1RM) nos exercícios supino e rosca scott, e relacioná-la com a massa corporal total (MCT) e com a massa corporal magra (MCM), bem como avaliar o número máximo de repetições em diferentes percentuais de 1RM. Onze mulheres (24 ± 1,4 anos) foram submetidas à avaliação da composição corporal, testes de 1RM e testes de repetições máximas em 50, 60, 70 e 80% de 1RM. No tratamento dos dados, foram utilizados a regressão linear múltipla, a ANOVA para medidas repetidas e o teste t pareado. A MCM é a variável que melhor explica a variância de 1RM, podendo ser utilizada para a determinação de um coeficiente para a estimativa da carga de treino. Houve diferenças significativas entre os números de repetições em todos os percentuais e em ambos os exercícios [(supino (p=0,000) e rosca scott (p=0,000)], sendo esses números progressivamente menores com o incremento da carga.
Objetivo: El objetivo del presente estudio es evaluar el efecto de la edad relativa en la selección de los atletas jóvenes y el rendimiento de los equipos de fútbol sala. Métodos: Se recopiló la fecha de nacimiento de 2.676 jóvenes atletas (femeninos: n=292; masculinos=2.384) que jugaban en las categorías Sub-9 a Sub-20 de fútbol sala brasileño. Los atletas fueron categorizados en base al cuartil y al semestre de nacimiento. La posición final de los equipos en el torneo fue categorizada como finalista, semifinalista y no semifinalista. Se aplicó la prueba chi-cuadrada, el V de Cramer y los modelos de regresión logística multinómica. Resultados: Los datos apoyaron la hipótesis sobre la tendencia a seleccionar atletas que nacieron en los primeros meses del año en equipos masculinos, pero no se observó lo mismo en equipos femeninos. Además, sólo los atletas de la categoría Sub-13 que nacieron en el primer semestre del año presentaran un 50% de posibilidades de estar entre los finalistas del torneo cuando se comparan con sus compañeros. Aplicaciones prácticas: La edad relativa tuvo efecto en el equipo de atletas masculinos jóvenes, pero tal efecto no se asoció con el rendimiento positivo de los equipos de fútbol sala, excepto para la categoría Sub-13. Por lo tanto, se recomienda a los entrenadores de atletas jóvenes valorar otros factores en el momento para seleccionar y componer sus equipos dentro del contexto evaluado aquí. Aim: The aim of the present study is to assess the effect of relative age on the selection of young athletes and the performance of futsal teams. Methods: The date of birth of 2,676 young athletes (female: n=292; male=2,384) playing in the U-9 to U-20 categories of Brazilian futsal was collected. The athletes were categorized based on quartile and on the semester of birth. The final position of the teams in the tournament was categorized as finalist, semifinalist and non-semifinalist. The chi-square test, the Cramer’s V and multinomial logistic regression models were applied. Results: The data supported the hypothesis about the trend to select athletes who were born in the first months of the year in male teams, but it was not observed in female teams. Additionally, only athletes in the U-13 category who were born in the first semester of the year present 50% chance to be among the finalists in the tournament when they are compared to their peers. Practical application: The relative age had effect on the team of young male athletes, but such an effect was not associated with the positive performance of futsal teams, except for the U-13 category. Thus, coaches of young athletes are recommended to value other factors at the time to select and compose their teams within the herein assessed context. Objetivo: O objetivo do presente estudo é avaliar o efeito da idade relativa na seleção de jovens atletas e o desempenho das equipes de futsal. Métodos: Foi coletada a data de nascimento de 2.676 jovens atletas (feminino: n=292; masculino=2.384) jogando nas categorias Sub-9 a Sub-20 do futsal brasileiro. Os atletas foram categorizados com base no quartil e no semestre de nascimento. As equipes foram agrupadas de acordo com a posição final no torneio como finalista, semifinalista e não semifinalista. Foram aplicados o teste de Qui-quadrado, V de Cramer e os modelos de regressão logística multinomial. Resultados: Os dados corroboraram a hipótese sobre a tendência de selecionar atletas nascidos nos primeiros meses do ano em equipes masculinas, mas isso não foi observado em equipes femininas. Além disso, apenas atletas da categoria Sub-13 que nasceram no primeiro semestre do ano apresentaram 50% de chance de estar entre os finalistas do torneio quando são comparados aos seus pares. Aplicações práticas: Houve efeito da idade relativa na seleção de jovens atletas do sexo masculino, mas tal efeito não esteve associado ao desempenho positivo das equipes de futsal, com exceção da categoria Sub-13. Assim, os treinadores de jovens atletas são recomendados a valorizar outros fatores no momento para selecionar e compor suas equipes dentro do contexto aqui avaliado.
OBJECTIVE: To determine the applicability and predictive accuracy of an isoinertial resistance machine for the assessment of hamstring/quadriceps conventional (concentric) ratio (CR). METHOD: Thirty-two resistance trained young men (23.53 ± 3.2 yrs) were tested using dedicated instruments to obtain the peak torque (PT) of the right knee extensors and flexors as well as the corresponding one repetition maximum (1RM) values. All measurements were conducted in the concentric mode. RESULTS: Significant (p < 0.05) correlations were indicated between knee extensor and flexor PT and 1RM values (r = 0.73 to 0.75), as well as between PT and 1RM CR values (r = 0.65). However the isoinertial CR values (0.42 ± 0.05) were significantly (p < 0.05) greater than their isokinetic counterparts (0.36 ± 0.04). CONCLUSION: Caution should be used when comparing isoinertial CR with population-specific isokinetic normative scores.
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