RESUMEN

This study compared the effects of two sprint-jump training programmes, performed on either sand or grass surfaces, on the sprint and jump performance of elite young soccer players over an 8-week training period. Fifteen under-20 soccer players were randomly allocated to the sand (n = 7) or grass (n = 8) group. Athletes performed 12 training sessions, comprising vertical and horizontal jump exercises, and linear and change-of-direction (COD) sprint drills. Pre- and post-measurements were completed in the following order: vertical jump, sprint speed at 10 m and 17 m, curve sprint (CS), and modified Zigzag COD tests. Between-group differences were determined using a two-way ANOVA with repeated measures and effect sizes (ES). No improvements in jump performance were found in either group. Significant increases were observed in the sand group for acceleration in 0-10 m and for 10- and 17-m linear sprint velocity (ES = 1.15, 1.16, and 1.81, respectively; P < 0.05). In contrast, no significant differences were detected for acceleration and linear sprint velocity in the grass group, comparing pre- and post-tests (ES ranging from 0.01 to 0.47; P > 0.05). Both sand and grass groups revealed similar increases in the CS and COD velocities after the training period (ES ranging from 0.98 to 1.93; P < 0.05). In conclusion, sprint-jump training programmes performed on both grass and sand surfaces elicited significant improvements in CS and COD performances, whereas acceleration and linear sprint velocity increased only in the sand group, after a short-term training period. The sand training surface was proven to be a practical strategy to improve sprint performance in all its forms in soccer players, which is of great interest and importance for coaches and sport scientists working in elite soccer.

RESUMEN

Introduction: To better understand the post-activation performance enhancement (PAPE) effect promoted by a plyometric conditioning activity (CA), the aim of this study was to investigate the temporal response of PAPE after a plyometric CA. Methods: Fourteen healthy and active adults visited the laboratory 3 times, with an interval of 7 days between each visit. On the first day they were familiarized with the countermovement jump (CMJ) test and plyometric CA. In the second and third visits, participants performed either plyometric CA or control (remaining seated) in a crossover design. The CMJ test was performed pre and 1-, 3-, 6-, and 9-min post the plyometric CA or control. The comparisons were performed using the repeated measure two-factor ANOVA and Bonferroni adjustment (significance level adopted P ≤ 0.05). Results: Time (P < 0.01), condition (P < 0.01), and interaction (P < 0.01) effects were reported for CMJ comparisons. For the control condition, CMJ increased at 3 min compared to pre (P = 0.03) and at 3 min compared to 1 min (P = 0.03). For the plyometric CA, CMJ increased at 1- (P < 0.01), 3- (P < 0.01), and 6-min (P = 0.02) compared to pre. For condition comparisons, CMJ was different at 1- (P < 0.01), 3- (P < 0.01), 6- (P < 0.01), and 9-min (P = 0.02). The Effect size of the comparisons of all moments compared to pre was null (d < 0.20) for control and small (d < 0.50) for plyometric CA. Discussion: It is possible to conclude that the plyometric CA promoted a PAPE effect for up to 9-min. Strength and conditioning coaches and practitioners may consider multiple sets of plyometric CA to produce immediate enhancement of power in the lower limbs.

RESUMEN

The objective was to evaluate the effects of acai supplementation (AS) on markers of muscle damage. Twelve men participated in the 21-day study. All performed the damage protocol (DP) in two moments, separated by 7 days. The DP consisted of 10 sets of 10 CMJs, with a recovery of 1 min between sets. The AS was performed for 7 days with 40 g/day of dehydrated acai (GA) or placebo (GP). Blood parameters (CK, LDH and Trolox-equivalent antioxidant capacity - TEAC) were evaluated at 0 h and 24 h. Ultrasound images (VL, RF and GM), DOMS in lower limbs and isometric peak torque (IPT) of knee extensors and flexors were evaluated at 0 h, 24 h, 48 h and 72 h after DP. A time-treatment interaction was observed for TEAC (p = 0.01), in which the GA presented increases of 11% after 24 h. Similarly, time-treatment interaction was observed for knee flexors IPT (p = 0.02), where GA showed superior recovery after 24 h (GA = 108 ± 23 vs. GP = 92 ± 24 N∙m) and 72 h (GA = 113 ± 31 vs. GP = 98 ± 26 N∙m). No significance was observed in the fatigue index for knee extensors (p = 0.75) and flexors (p = 0.89), indicating similar fatigue in both situations. We concluded that AS increased the TEAC and promoted faster recovery of the knee flexors IPT when compared to GP.

RESUMEN

This study aimed to compare the post-activation performance enhancement induced by successive drop-jumps performed on hard and sand surfaces in sprint and jump performance of top-level sprinters. Athletes were tested on two occasions. On each visit they were allocated to one of the experimental protocols, which consisted of performing 2x5 drop-jumps from a box with the height of 60-cm on hard or sand surfaces in randomized order, seven days apart. Prior to and 7 and 15-min after executing drop-jumps, sprinters performed countermovement jumps and 60-m sprint tests. Differences between sprinting splits and surfaces were assessed using a two-way analysis of variance with repeated measures. No significant differences in jump height or sprint time were observed (p>0.05), regardless of the surface used (i.e., hard or sand) during the conditioning activity (effect sizes [95% confidence intervals] ranging from 0.01 [-0.84;0.84] to 0.44 [-0.42;1.27]). Performing drop-jumps on sand or hard surfaces immediately before maximum sprinting bouts does not provide any advantage or disadvantage to top-level sprinters. Sprint coaches may prescribe short-plyometric training activities on sand surfaces even close to competitions, bearing in mind that this strategy will not compromise sprint-specific performance.

RESUMEN

The objective of this study was to evaluate the effects of a training session with and without an intervention of postactivation performance enhancement (PAPE) on countermovement jump (CMJ) height, perceived recovery status (PRS), and ratings of perceived exertion (RPEs), followed by a specific volleyball training session. The sample consisted of sixteen professional male volleyball players, with an average age of 26.8±6.1 years and average height of 195.9±6.7 cm, randomly divided into a group with PAPE intervention (GPAPE) (n=8), and a control group (CTRL) without PAPE intervention (n=8). The control group carried out the training session with plyometric exercises, and the GPAPE added conditioning protocols for PAPE to plyometric training, followed by a technical tactical volleyball session. At the end of the training session, there was an increase of 16.3% in the height of the CMJ in the GPAPE, while the CTRL showed a decrease of 5% in the height of the CMJ. PRS and RPE variables did not differ between the groups. It was concluded that PAPE had a positive effect on the height of the vertical jump after plyometric training, which was maintained until the end of the technical and tactical volleyball session.

RESUMEN

Resumen La velocidad juega un papel fundamental en el rendimiento deportivo, tanto en deportes individuales como colectivos. Los objetivos de este estudio son: a) determinar el efecto agudo de los tipos de entrenamiento de fuerza, velocidad, pliometría y velocidad contra resistencia en la carrera de velocidad y sus fases y b) realizar el análisis del efecto agudo de estos tipos de entrenamiento de manera individual. Once velocistas (edad promedio de 21.8 años ± 3.04, talla de 1.764 m ± 0.062 y peso de 69.645 kg ± 4.946), con experiencia como velocistas realizaron cinco tratamientos agudos (F, V, P, VR y control), para los cuales se aleatorizó el orden. Para cada tratamiento, realizaron un pre test y un post test de 100 metros con mediciones de intervalos cada 20 metros. Se realizaron 2 análisis de varianza (ANOVA) de medidas repetidas de 2 y 3 vías, con el objetivo de analizar el efecto de los tratamientos en el tiempo total de carrera y en cada uno de los intervalos de la carrera de velocidad, respectivamente. También, se realizó un análisis individual, utilizando estadísticos descriptivos y gráficos. No hubo interacción significativa entre las mediciones y los tipos de entrenamiento (F = 1.733 p = .162), ni entre las mediciones, los tipos de entrenamiento y los intervalos de distancia (F = 0.569 p = .903). En el análisis individual, se observa como los cambios en la velocidad según el tipo de tratamiento varían entre sujetos, siendo el tratamiento de velocidad con el que más sujetos mejoran.

Abstract Speed plays a key role in performance in both collective and individual sports. The objectives of this study are: a) to determine the acute effect of strength, speed, plyometric, and resisted sprint trainings in sprinting and its phases, and b) to analyze the acute effect of these types of training on an individual manner. Eleven experienced sprinters (mean age 21.8 ± 3.04, height 1.764 m ± 0.062, and weight 69.645 kg ± 4.946) participated in five training sessions (S, SP, P, RS, and control) assigned in a random order. For each treatment, 100 meter-pre and post-tests were conducted with interval measurements every 20 meters. Two-way and three-way variance analyses (ANOVA) of repeated measurements were conducted to analyze the effect of the types of training on the total race time and in each interval, respectively. In addition, descriptive statistics and graphs were used for an individual analysis. For the group analysis, no significant interaction was found between measurements and the types of training (F = 1.733 p = .162) or between measurements, types of training, and distance intervals (F = 0.569 p = .903). However, in the individual analysis, changes in speed based on the type of treatment vary between subjects, being speed the treatment that shows more improvement in subjects.

Resumo A velocidade tem um papel fundamental no desempenho esportivo, tanto em esportes individuais quanto coletivos. Este estudo tem como objetivo: a) determinar o efeito agudo dos tipos de treinamento de força, velocidade, pliometria e velocidade contrarresistência na corrida de velocidade e suas fases e b) realizar a análise do efeito agudo destes tipos de treinamento de maneira individual. Onze velocistas (idade média de 21,8 anos ± 3,04, altura de 1,764 m ± 0,062 e peso de 69,645 kg ± 4,946), com experiência como velocistas realizaram cinco tratamentos agudos (F, V, P, VR e controle), para os quais se aleatorizou a ordem. Para cada tratamento, foram realizados um pré-teste e um pós-teste de 100 metros com medições de intervalos a cada 20 metros. Foram realizadas 2 análises de variância (ANOVA) de medidas repetidas de 2 e 3 vias, a fim de analisar o efeito dos tratamentos no tempo total de corrida e em cada um dos intervalos da corrida de velocidade, respectivamente. Também, foi realizada uma análise individual, utilizando estatísticos descritivos e gráficos. Não houve interação significativa entre as medições e os tipos de treinamento (F = 1,733 p = 0,162), nem entre as medições, os tipos de treinamento e os intervalos de distância (F = 0,569 p = 0,903). Na análise individual, observa-se como as mudanças na velocidade segundo o tipo de tratamento variam entre sujeitos, sendo o tratamento de velocidade com o que mais sujeitos melhoram.

Asunto(s)

RESUMEN

RESUMEN Introducción: La fuerza explosiva es la capacidad física de generar una mayor fuerza muscular en un menor tiempo sin pérdida de eficacia, lo que es un componente determinante de la preparación deportiva y un indicador indirecto del rendimiento en lucha deportiva. Objetivo: Mejorar la fuerza explosiva en miembros inferiores a través de ejercicios pliométricos en luchadores libres, categoría senior. Métodos: Estudio cuasi-experimental de corte correlativo, para el cual se aplicó un programa pliométrico de tres fases, en miembros inferiores, conformado por una población de 15 luchadores (sexo masculino, sub-21 años), y fue evaluado el estímulo en la capacidad fuerza explosiva. Resultados: Se estableció mejoras significativas en la prueba de salto vertical (SV: p = 0,000), salto horizontal (SH: p = 0,000), carrera en 20 m (C20m: p = 0,000) y el test de salto 8 (S8: p = 0,001), y en todos los casos se favoreció al postest. Se determinó una correlación lineal positiva moderada entre SV y SH (0,50), una correlación negativa moderada entre SH y C20m (-0,58), una correlación negativa muy baja entre SV y C20m (-0,03), una correlación positiva moderada entre SV y S8 (0,61), una correlación positiva muy baja entre SH y S8 (0,16) y una correlación positiva moderada entre C20m y S8 (0,59). Conclusiones: Con la intervención pliométrica se demuestra una mejora significativa en la fuerza explosiva de miembros inferiores, lo que resulta en una alternativa eficaz para mejorar indirectamente el rendimiento deportivo. De las 6 correlaciones lineales realizadas, 4 fueron de índole moderada, esto evidencia que la potenciación pliométrica de un plano muscular específico puede mejorar consecutivamente otros planos musculares relacionados con la rapidez y la fuerza explosiva.

ABSTRACT Introduction: Explosive strength is the physical capacity to generate greater muscular strength in a shorter time without losing effectiveness. This is a crucial component of sports training and an indirect indicator of yield in wrestling. Objective: Improve the explosive strength of the lower limbs through plyometric exercises performed by senior freestyle wrestlers. Methods: A correlational quasi-experimental study was conducted based on a three-stage plyometric program for the lower limbs. The study population was 15 wrestlers (male sex, age under 21 years) who were evaluated for explosive strength capacity. Results: Significant improvement was established in the following tests: vertical jump (VJ: p = 0.000), horizontal jump (HJ: p = 0.000), 20-meter dash (D20m: p = 0.000) and jump 8 (J8: p = 0.001). In all cases the post-test obtained better results. Determination was made of a moderate positive linear correlation between VJ and HJ (0.50), a moderate negative correlation between HJ and C20m (-0.58), a very low negative correlation between VJ and C20m (-0.03), a moderate positive correlation between VJ and J8 (0.61), a very low positive correlation between HJ and J8 (0.16) and a moderate positive correlation between C20m and J8 (0.59). Conclusions: The plyometric intervention was found to significantly improve the explosive strength of lower limbs, thus becoming an effective alternative to indirectly enhance sport yield. Of the six linear correlations performed, four were moderate, which shows that plyometric strengthening of a specific muscular plane may consecutively improve other muscular planes related to speed and explosive strength.

Asunto(s)

RESUMEN

Introducción: El método pliométrico es un modelo de estiramiento-acortamiento orientado a la mejora de la velocidad y la potencia en deportistas. Si bien existen investigaciones que valorar los efectos de la pliometría en futbolistas masculinos de diferentes rangos etarios, existe la necesidad de valorar los alcances y limitaciones de la aplicación pliométrica en el sexo femenino a corto plazo. Objetivo: Determinar la incidencia del método pliométrico a corto plazo en la velocidad y velocidad-fuerza en mujeres futbolistas de la categoría senior. Métodos: Se estudió la población de mujeres futbolistas de categoría senior (18 sujetos), implementando un programa pliométrico de 3 microciclos de adaptación inicial y 5 microciclos de intervención pliométrica, se valoró los efectos en la velocidad y la velocidad-fuerza a través de dos pruebas de valoración del rendimiento deportivo, antes y después de implementada la propuesta. Resultados: Se evidenciaron mejorías significativas en el postest como parte del Jump test (p=0,000), y significativas en el postest de las tres fases de la prueba de 40m (p= 0,000). Conclusiones: se demuestran mejoras significativas en las capacidades de velocidad y velocidad-fuerza en mujeres futbolistas de la categoría senior, indicando para el presente estudio que el entrenamiento pliométrico es efectivo en el sexo femenino para potenciar los indicadores del rendimiento deportivo antes mencionados(AU)

Introduction: The plyometric method is a stretch-shortening model aimed at improving the speed and strength of sportspeople. Studies have been conducted assessing the effects of plyometrics on male soccer players of various age ranges. It is therefore necessary to evaluate the short-term scope and limitations of the plyometric method as applied to female players. Objective: Determine the short-term impact of the plyometric method on the speed and speed-strength of female soccer players from the senior category. Methods: A study was conducted of a population of female soccer players from the senior category (18 subjects), implementing a plyometric program composed of three microcycles for initial adaptation and a five-microcycle plyometric intervention. Evaluation was performed of the effects on speed and speed-strength applying two sport performance tests, one before and one after implementation of the proposal. Results: Improvement was significant in the post-test as part of the jump test (p= 0.000), as well as in the post-test for the three phases of the 40 m test (p= 0.000). Conclusions: Significant speed and speed-strength improvement is observed in female soccer players from the senior category, showing that plyometric training is effective to strengthen the aforementioned sport performance indicators in the female sex(AU)

RESUMEN

A pliometria utiliza a capacidade reativa do sistema neuromuscular para aumentar a potência do movimento partindo de uma contração excêntrica para uma concêntrica. A isometria referese a uma modalidade estática de treinamento, ou seja, não há alteração no comprimento da fibra muscular. O handebol é uma modalidade esportiva coletiva que envolve uma grande quantidade e variedade de movimentação associada à manipulação de bola e interação com outros atletas. Em termos de movimentação, o handebol pode ser considerado um esporte completo, pois utiliza uma rica combinação das habilidades motoras fundamentais e "naturais" do repertório motor do ser humano. O objetivo da pesquisa é analisar a influência de 4 semanas de treinamento pliométrico e isométrico na força explosiva de jovens atletas de handebol. A amostra contou com 10 mulheres, com média de idade de 16,1 ± 0,56 anos, praticantes de handebol há pelo menos três meses. O protocolo de avaliação utilizado foi: salto horizontal (SH) para mensurar força explosiva de membro inferior. As meninas foram divididas em dois grupos estatisticamente iguais, o grupo pliométrico (GP) e o isométrico (GI). Os dados foram analisados através de testet pareado e Effect Size (magnitude de efeito), além do manual Proesp. Inicialmente os testes apresentaram os seguintes resultados: o GP mostrou 1,32 ± 0,13m no SH e o GI 1,41 ± 0,10m. Após quatro semanas de treinamento foram refeitos os testes e o GP evidenciou 1,37 ± 0,08m no SH e o GI 1,43 ± 0,09m. Estatisticamente as mudanças não se apresentaram significativas, a magnitude do efeito os resultados de força explosiva de membros inferiores mostraramse superficiais. Concluise então que apesar de estatisticamente insignificantes, ambos os métodos apresentam pequena evolução na força explosiva de membros inferiores, e cabe analisar maior tempo dos métodos nesses ganhos e também analisar uma proposta concomitante entre ambos os métodos

Plyometrics uses the reactive capacity of the neuromuscular system to increase the power of movement from an eccentric to a concentric contraction. Isometry refers to a static mode of training, ie there is no change in muscle fiber length. Handball is a collective sport that involves a large amount and variety of movement associated with ball manipulation and interaction with other athletes. In terms of movement, handball can be considered a complete sport because it uses a rich combination of fundamental and "natural" motor skills of the human motor repertoire. The aim of this research is to analyze the influence of a 4 week plyometric and isometric training on the explosive strength of young handball athletes. The sample consisted of 10 women, with an average age of 16.1 ± 0.56 years, who had been practicing handball for at least three months. The evaluation protocol used was: horizontal jump (HS) to measure lower limb explosive strength. The girls were divided into two statistically equal groups, the plyometric group (GP) and the isometric group (GI). Data were analyzed using paired ttest and Effect Size, as well as the Proesp manual. Initially the tests presented the following results: GP showed 1.32 ± 0.13m in HS and GI 1.41 ± 0.10m. After four weeks of training, the tests were redone and the GP showed 1.37 ± 0.08m in HS and the GI 1.43 ± 0.09m. Statistically the changes were not significant, the magnitude of the effect and the lower explosive strength results were superficial. It is concluded that, although statistically insignificant, both methods present little evolution in the explosive force of lower limbs, and it is necessary to further analyze the methods in these gains and also to analyze the concurrent proposal between both methods.

La pliometría utiliza la capacidad reactiva del sistema neuromuscular para aumentar el poder de movimiento de una contracción excéntrica a una concéntrica. La isometría se refiere a un modo estático de entrenamiento, es decir, no hay cambios en la longitud de la fibra muscular. El balonmano es un deporte colectivo que involucra una gran cantidad y variedad de movimientos asociados con la manipulación del balón y la interacción con otros atletas. En términos de movimiento, el balonmano puede considerarse un deporte completo porque utiliza una rica combinación de las habilidades motoras fundamentales y "naturales" del repertorio motor humano. El objetivo de esta investigación es analizar la influencia de 4 semanas de entrenamiento pliométrico e isométrico en la fuerza explosiva de los jóvenes atletas de balonmano. La muestra consistió en 10 mujeres, con una edad promedio de 16.1 ± 0.56 años, que habían practicado balonmano durante al menos tres meses. El protocolo de evaluación utilizado fue: salto horizontal (HS) para medir la fuerza explosiva de la extremidad inferior. Las niñas se dividieron en dos grupos estadísticamente iguales, el grupo pliométrico (GP) y el grupo isométrico (GI). Los datos se analizaron usando la prueba t pareada y el Tamaño del efecto, así como el manual Proesp. Inicialmente, las pruebas presentaron los siguientes resultados: GP mostró 1.32 ± 0.13m en HS y GI 1.41 ± 0.10m. Después de cuatro semanas de entrenamiento, las pruebas se rehicieron y el GP mostró 1.37 ± 0.08m en HS y el GI 1.43 ± 0.09m. Estadísticamente, los cambios no fueron significativos, la magnitud del efecto y los resultados de menor fuerza explosiva fueron superficiales. Se concluye que, aunque estadísticamente insignificante, ambos métodos presentan poca evolución en la fuerza explosiva de las extremidades inferiores, y es necesario analizar un mayor tiempo de los métodos en estas ganancias y también analizar una propuesta concurrente entre ambos métodos.

Asunto(s)

RESUMEN

The aim of this study was to investigate the differences in loaded and unloaded jump performances between different age categories of top-level volleyball players from the same club. Forty-three volleyball players were divided into four age groups: under-17, under-19, under-21 and professional. Vertical jumping height for squat jump (SJ), countermovement jump (CMJ) and CMJ with arm swing (CMJa) and mean propulsive velocity (MPV) in the loaded jump squat exercise with 40% of the athlete's body mass were compared among the different age categories, considering body mass as a covariate. SJ and CMJ jump height values were higher for professional and under-21 players than under-17 players (p<0.05). CMJa height was higher for under-21 players than under-19 and under-17 players (p<0.05). MPV in the loaded jump squat was higher for under-21 players than under-17 players (p<0.05). From a general perspective, these results suggest that aging per se is not capable of substantially improving loaded and unloaded vertical jump performances across different age categories of top-level volleyball players. Therefore, to increase the vertical jumping ability of these team sport athletes throughout their long-term development, coaches and strength and conditioning professionals are encouraged to implement consistent neuromuscular training strategies, in accordance with the specific needs and physiological characteristics of each age group.

RESUMEN

This study aimed at testing whether there are mean propulsive velocities (MPVs) capable of maximising the mean propulsive power (MPP) during the execution of bench press (BP), bench throw (BT), half squat (HS) and jump squat (JS). Additionally, we assessed the differences in MPP/MPV between ballistic and traditional exercises. Seventeen male rugby sevens players performed MPP tests in BP, BT, HS and JS and maximum isometric force (MIF) tests in HS and BP. The JS presented higher MPP (977.4 ± 156.2 W) than the HS (897.9 ± 157.7 W) (P < 0.05); the BP (743.4 ± 100.1 W) presented higher MPP than the BT (697.8 ± 70.4 W) (P < 0.05). Ballistic exercises presented higher optimum MPV (JS = 1.02 ± 0.07 m·s-1; BT = 1.67 ± 0.15 m·s-1) than traditional exercises (HS = 0.93 ± 0.08 m·s-1; BP = 1.40 ± 0.13 m·s-1) (P < 0.05). The optimum MPP in the JS, BT, HS and BP occurred at 28.2 ± 5.79, 23.3 ± 4.24, 32.4 ± 9.46 and 27.7 ± 5.33% of the MIF, respectively. The coefficient of variation (CV) of MPV at optimum MPP ranged from 7.4% to 9.7%, while the CV of %MIF ranged from 18.2% to 29.2%. The MPV is a more precise indicator of the optimum loads than the percentages of MIF due to its low inter-subject variability as expressed by CV. Therefore, MPV can be used to determine the optimum power load in the four investigated exercises.

Asunto(s)

RESUMEN

This study compared the values of bar-peak force (PFBar) and power (PPBar), body-peak force (PFBody) and power (PPBody) and bar-mean propulsive power (MPPBar) in different jump-squat (JS) conditions: unloaded condition (UC); bar-loaded condition (BLC) and optimum bar-MPP condition (OBC). Twenty-five soccer players performed the JS using a bar with negligible mass (UC), using the Smith-machine bar (BLC) and using the load capable of maximizing the bar-MPP (OBC). The PFBody was significantly higher in the UC (2847.9 ± 489.1 N) than in the OBC (2655.4 ± 444.3 N). The UC presented greater PPBody (3775.9 ± 631.5 W) than the BLC (3359.7 ± 664.3 W) and OBC (3357.8 ± 625.3 W). The OBC presented higher values of PFBar, PPBar and MPPBar (676.2 ± 109.4 W) than the BLC (MPPBar = 425.8 ± 53.7 W) (all p < 0.05). In the OBC (compared to the UC), the body peak-power presented a reduction of ≈ 11%, while generating bar-power output from ≈ 59 to 73% higher than the BLC. While the fact that the body-peak power is maximized in the UC denotes a mechanical phenomenon, the bar-optimum load represents an intensity at which both components of the power equation (force and velocity) are optimized. This has important implications for sports training.

RESUMEN

This study compared the physical performance of Paralympic sprinters with visual impairments (PSVI) and their guides in jump and sprint tests. Ten PSVI and guides executed squat jumps (SJ), countermovement jumps (CMJ), horizontal quintuple right/left-leg jumps (QR/QL), decuple jumps (DEC), and 50-m-sprint tests. The guides were superior to the PSVI in SJ (35.9 ± 6.3 vs 45.6 ± 3.2 cm), CMJ (38.5 ± 6.2 vs 46.7 ± 4.0 cm), QR (9.2 ± 1.9 vs 12.7 ± 1.0 m), QL (9.4 ± 1.9 vs 13.1 ± 0.8 m), DEC (21.0 ± 3.3 vs. 27.2 ± 1.7 m), and 50-m sprints (8.4 ± 0.4 vs 7.6 ± 0.5 m/s). The average differences between the PSVI and guides in the sprint tests was 10%, range 1-24%. Therefore, substantial differences in sprinting speed (in favor of the guides) between the peers were observed. Coaches should develop strategies to train the guides to improve their muscle-power performance.

Asunto(s)

RESUMEN

En el presente estudio se aplicó un entrenamiento pliométrico adaptado a un grupo de niños (n=15) no deportistas (12,8±0,8 años; 1,56±0,09 M; 48,7±8.5 Kg.), durante un período de seis semanas de entrenamiento (dos veces por semana). El objetivo fue demostrar si es posible aumentar la potencia (P) de extremidades inferiores mediante el aumento del índice elástico (IE). Se midieron los saltos Squat Jump (SJ), y Countermovement Jump (CMJ) y se calculó P e IE. Los resultados del pre-entrenamiento (SJ=26,51±5,1 cm; CMJ=28,52±6,5 cm; P=1834±853,04 W; IE 8,17±3,7 %) y post-entrenamiento (SJ=28,46±6,2 cm; CMJ=32,07±6,9 cm; P=2018±871,39 W; IE=13,23±1,9 %) indican que se aumentó significativamente la variable IE (p0,05). Los resultados obtenidos demuestran que este tipo de entrenamiento pliométrico puede estimular el componente elástico y neuromuscular en desmedro del componente contráctil, al obtenerse una ganancia relativa de potencia, situación preponderante en la etapa dedesarrollo de los niños.

This study aims to determine the current state of the relation between these variables, in studentsof the Rafael J. Mejia School, in Sabaneta. A stratified simple of 207 students (99 noys, 44%108 girls, 56%) was randomly selected from a total of 455 students. We applied measurementprocedures and evaluation proposed by J uregui and Ordo¤ez (1993). The results showed that aconsiderable proportion of the sample was above the 75th percentile for anthropometric tests andskinfolds; below the 25th percentile in physical abilities. This suggests that there is a tendency inthese children to obesity and physical inactivity.

Asunto(s)

RESUMEN

OBJECTIVES: To determine the residual acute vibration-stretching effect on preactivation levels, short-latency stretch reflex, and performance during execution of drop jumps. DESIGN: Repeated measures. METHODS: Eleven male recreational athletes performed a set of three 45cm drop jumps before and immediately after a 30s static stretching exercise with and without simultaneously imposed muscle vibration (45Hz, 5mm). Drop jump height, ground reaction forces and electromyographic data including Vastus Lateralis onset/levels of preactivation and short-latency stretch reflex were recorded. RESULTS: No changes were induced on drop jump height. However, stretching-induced decrements on ground reaction force peak and time to peak as well as an increment in contact time followed a delay in short-latency stretch reflex onset and a reduced preactivation level of Vastus Lateralis. Otherwise, when vibration was simultaneously imposed, there was no evidence of changes in high-speed force production variables or electromyographic recordings. CONCLUSIONS: Mechanical vibration, when applied simultaneously to static-stretching routines, appeared to be effective to counteract decreased musculotendinous unit stiffness-induced high-speed force production deficit during jumping performance.

Asunto(s)

RESUMEN

Se comparó el efecto del entrenamiento de carrera inclinada con un método de entrenamiento con saltos múltiples sobre la potencia en el salto en jugadores universitarios de baloncesto. Para tal fin, se realizó un estudio aleatorio comparativo en 20 sujetos de 23 años, desviación estándar 2,2 y de 182 cm de talla, desviación estándar 9 cm, los cuales se dividieron en dos grupos, uno de entrenamiento pliométrico (n = 10) y el otro de entrenamiento de carrera inclinada (n = 10). Se aplicaron test de campo, salto largo, salto vertical (Detent), salto vertical con un paso de impulso y Abalakov, antes de empezar el entrenamiento, en la semana 8 y en la semana 12. En el grupo de entrenamiento de carrera inclinada se encontraron diferencias significativas en los promedios del salto largo de la semana 8 y 12 (p=0,09 y p=0,03, respectivamente) y después de 12 semanas en el Detent (p=0,0722). Los hallazgos de este estudio indican que el entrenamiento de carrera inclinada es efectivo para incrementar la fuerza explosiva de jóvenes jugadores de baloncesto.

Running uphill as a training method was compared to multiple jumps to improve jumping power in young male basketball players. We carried out a randomized comparative study with 20 male players (23 ± 2,2 years and 182 ± 9 cm) who were randomly assigned to tbe plyometric (n= 10) or running uphill (n= 10) training groups. Jumping ability was determinate through field test (standing long jump, vertical jump, vertical jump with step, and Abalakow´s tests) before training and after 8/12 week post-training. Standing long jump results were significantly higher in the group practicing running uphill compared to plyometrics after 8/12 weeks of training (p=0,09 and p=0,03, respectively). Moreover, vertical jump results were also significantly higher after 12 weeks (p=0.0722). These findings show that running uphill is at least as effective, and even better than the multiple jumps training method for improving explosive strength in young male basketball players.

Asunto(s)

RESUMEN

El objetivo de este estudio ha sido predecir la altura optima de caída (AOC) en los ejercicios pliométricos Drop Jump (DJ) a partir de variables cinemáticas y antropométricas, mediante un modelo de regresión múltiple lineal. Participaron en el estudio 13 sujetos, 6 hombres y 7 mujeres de la liga vallecaucana de atletismo. Inicialmente se determinó la altura de vuelo y longitud de los saltos efectuados con las pruebas físicas Countermovement Jumps (CMJ), Abalakov (ABK), salto largo sin/con impulso de brazos, el tiempo en carreras de 30 y 100 m. Se determinó la composición corporal en % y Kg. (músculo, grasa, óseo y residual) por ecuaciones de regresión (Yuhasz, Mateigka, De Rose, etc.) Además, se valoró utilizando la plataforma de contacto la AOC a partir de los índices de fuerza reactiva (RSI), coeficiente de calidad del salto (CQ), capacidad reactiva del músculo (CR) que se determinan usando los tiempos de contacto y vuelo. La información se analizó con estadística descriptiva e inferencial principalmente con análisis de correlación, regresión lineal múltiple y pruebas no paramétricas para el modelo de regresión. En la AOC con utilización de brazos, el salto largo explicó por sí solo un 99,6% de la variabilidad en la AOC. La variable anterior combinada con el tiempo en 100 m. permitió explicar un 99,8% de la variabilidad en la AOC. Al añadir a la ecuación anterior el porcentaje de asa muscular se pudo explicar un 99,9% de la variabilidad en la AOC. Añadiendo a la ecuación el porcentaje graso se explicó 99,9% de la variabilidad en la AOC.

The aim of this study was to find out if it is possible to predict the land optimal height (AOC) of the plyometric jump (DJ) from kinematic and anthropometric variables using a multiple linear regression model. Thirtee subjects, 13, 6 male and 7 female athletics runners and jumpers of Liga Vallecaucana de Atletismo First, the height of the flight y long jump during the performance of the “countermovement jump” (CMJ), Abalakov, long jump with/without arms impulse, time in 30, 100 m were determined. Then, the corporal composition in % and Kg. (muscle, fat, bone and residual tissue), using Yuhasz, Mateigka, and De rose equations. So, with the contact platform calculate the several index: reactive strength index (RSI), quality coefficient (CQ) and muscle reactive output (CR) using flight and contact times. The information was analize with descriptive and inferential statistics meanly correlation, regression linear and non parametric tests for the regression model. In the AOC using arms, long jump explain 99,6% of the variability. the Prediction power was increased to 99,8% including in the model 100 m time. The inclusion of the muscle mass, as a third variable, raised the prediction power to 99,9% of land optimal height variability. Adding to the corporal fat (%) to the model, the prediction power was 99,9% too.

Asunto(s)