Effects of traditional judo training session on muscle damage symptoms.

BACKGROUND: This study aimed to analyze the acute effects of a judo training session on muscle strength, delayed-onset muscle soreness (DOMS), and serum creatine kinase (CK) activity. METHODS: Ten male judo athletes participated in this study and performed a 90-min traditional judo training session. The following measurements were performed before and 48 hours after the training: shoulder external/internal rotation isokinetic torque, countermovement jump (CMJ), DOMS, and blood draw for serum CK analysis. Student's t-test with significance level set at 5% and, effect size analysis were used. RESULTS: Significant reduction was found in jump height in the CMJ after the training session (2.9%; moderate effect; P=0.02). No significant differences were observed in any of the measures of shoulder external/internal rotation isokinetic torque (P>0.05). An increase of the serum CK (49.4%; moderate effect; P=0.01) and DOMS (20.6%; large effect; P=0.003) were noted after the training session when compared to baseline. CONCLUSIONS: Judo training session resulted in increased serum CK activity, and muscle soreness. The decrease of CMJ performance indicates impairment in the lower-limbs muscle power production. However, the lack of difference of shoulder external/internal rotation torque before and 48 hours after the training session may indicate that the interval was enough to recover the upper-limbs strength in judokas of this study. These markers of muscle damage can be used to control muscle adaptation progress and to avoid sports-related disorders of athletes with similar characteristics to those evaluated in this study.

Effect of different knee starting angles on intersegmental coordination and performance in vertical jumps.

This study aimed to analyze the effect of different knee starting angles on jump performance, kinetic parameters, and intersegmental coupling coordination during a squat jump (SJ) and a countermovement jump (CMJ). Twenty male volleyball and basketball players volunteered to participate in this study. The CMJ was performed with knee flexion at the end of the countermovement phase smaller than 90° (CMJ(<90)), greater than 90° (CMJ(>90)), and in a preferred position (CMJ(PREF)), while the SJ was performed from a knee angle of 70° (SJ(70)), 90° (SJ(90)), 110° (SJ(110)), and in a preferred position (SJ(PREF)). The best jump performance was observed in jumps that started from a higher squat depth (CMJ(<90)-SJ(70)) and in the preferred positions (CMJ and SJ), while peak power was observed in the SJ(110) and CMJ(>90). Analysis of continuous relative phase showed that thigh-trunk coupling was more in-phase in the jumps (CMJ and SJ) performed with a higher squat depth, while the leg-thigh coupling was more in-phase in the CMJ(>90) and SJ(PREF). Jumping from a position with knees more flexed seems to be the best strategy to achieve the best performance. Intersegmental coordination and jump performance (CMJ and SJ) were affected by different knee starting angles.

Effects of successive judo matches on fatigue and muscle damage markers.

This study aimed to investigate the acute effects of simulated judo matches on fatigue and muscle damage markers. Twenty male judo athletes participated in this study. The athletes performed three 5-minute judo matches separated by 15 minutes of passive rest between each match. The following measurements were performed before and after each match: shoulder external/internal rotation isokinetic torque and countermovement jump (CMJ). Blood samples were taken before the first match and after the third match for serum creatine kinase (CK) and lactate dehydrogenase (LDH) analysis. T-tests for dependent samples and analysis of variance for repeated measures were used to compare the variables over the time; the level of significance was set at 0.05. An overall effect of the successive matches on shoulder internal (PTIN) and external (PTEX) rotation peak torque and CMJ performance was observed. PTIN and PTEX showed significant decreases in postmatch 2 and postmatch 3 when compared with the baseline (p < 0.01). Also, CMJ height declined in postmatch 2 and postmatch 3 (p < 0.01) when compared with the baseline. Serum CK and LDH activity increased significantly after the third match (p < 0.01). It was concluded that 3 successive judo matches induced a decline of peak torque and muscle power in the upper and lower limbs, respectively, and also provoked an increase of muscle damage markers. These findings may provide important knowledge for coaches and physical trainers to improve judo-specific strength training in both the upper and lower limbs.

Reliability and validity of the 30-s continuous jump test for anaerobic fitness evaluation.

OBJECTIVES: To determine the test-retest reliability and concurrent validity of the 30-s continuous jump (CJ30) test using the Wingate test as a reference. DESIGN: Descriptive validity study. METHODS: Twenty-one male volleyball players (23.8 ± 3.8 years; 82.5 ± 9.1 kg; 185 ± 4.7 cm) were tested in three separate sessions. The first and second sessions were used to assess the reliability of the CJ30 while in the third session the Wingate test was performed. In the continuous jump test, consisting of maximal continuous jumps performed for 30s, jump height was determined by video kinematic analysis. Blood samples were collected after each test to determine lactate concentration. RESULTS: The CJ30 showed excellent test-retest reliability for the maximal jump height (ICC = 0.94), mean vertical jump height (ICC = 0.98) and fatigue index (ICC = 0.87). Peak lactate showed moderate reliability (ICC = 0.45). Large correlations were found between the mean height of the first four jumps of CJ30 and the peak power of the Wingate (r = 0.57), between the mean vertical jump height of CJ30 and the mean power of the Wingate (r = 0.70) and between the lactate peak of CJ30 and Wingate (r = 0.51). A moderate correlation of fatigue index between CJ30 and the Wingate was found (r = 0.43). CONCLUSIONS: The continuous jump is a reliable test and measures some of the same anaerobic properties as WAnT. The correlations observed in terms of anaerobic indices between the tests provide evidence that the CJ30 may adequately assess anaerobic performance level.

Respuestas fisiológicas y neuromusculares en esprines repetidos con cambio de dirección y en línea recta / Physiological and neuromuscular responses in the shuttle and straight line-repeated sprint running

Introducción: El objetivo de este estudio fue comparar y relacionar el rendimiento en sprint repetidos con cambio de dirección (ERCD) y en línea recta (ERLR), y comparar las respuestas fisiológicas y neuromusculares obtenidas post-ERCD y post-ERLR. Material y métodos : Formaron parte del estudio 14 jugadores de fútbol sala que realizaron sprint (25 m) con cambio de dirección y en línea recta. Se evaluó el rendimiento en los sprint (tiempo medio, mejor tiempo e índice de fatiga) y el countermovement jump (CMJ) antes y después de las 2 pruebas, además de las concentraciones de lactato en sangre (LACPEAK) después de los sprint. Resultados: El tiempo medio (TM) y mejor tiempo (MT) fueron más bajos en los ERLR (p < 0,01), mientras que el índice de fatiga fue más bajo en los ERCD (p = 0,02). Se observaron correlaciones entre TMLR y TMCD (r = 0,79), así como entre MTLR y MTCD (r = 0,69). Se encontraron diferencias en el rendimiento del CMJ entre los valores basales y post-ERLR (p = 0,01), así como con el post-ERCD (p = 0.02). No hubo diferencias entre el rendimiento del CMJ (p = 0,08) y LACPEAK (p = 0,09) entre post-ERLR y post-ERCD. Conclusiones: A pesar de las diferencias entre MT y TM en las 2 pruebas de sprint repetidos, el TM presentó gran correlación, sugiriendo que la capacidad de sprint repetidos es una calidad general y no depende de los cambios de dirección. Además, tanto la demanda glucolítica como la neuromuscular no fueron diferentes entre las 2 pruebas de sprint (AU)

Introduction: The aim of the present study was to compare and analyze the performance in the shuttle (RSS) and straight line (RSL) repeated sprint running and to compare the physiological and neuromuscular responses obtained post-RSL and post-RSS. Material and methods: Fourteen male futsal players performed 25 m sprints in a straight line and with a change of direction. The sprint performances (mean time, best time and fatigue index), countermovement jump (CMJ) performance were evaluated before and after both tests, as well as measuring blood lactate concentrations (LACPEAK) after the sprints. Results: The mean time (MT) and best time (BT) were lower in the RSL (P < 0.01), while the fatigue index was lower in the RSS (P = 0.02). Significant correlations were found between MTRSL and MTRSS (r = 0.79), as well as between BTRSL and BTRSS (r = 0.69). Significant differences in CMJ performance were recorded between baseline and post-RSL (P = 0.01), as well as between baseline and post-RSS (P = 0.02). No significant differences were found between CMJ performance (P = 0.08) and LACPEAK (P = 0.09) and post-RSL and post-RSS. Conclusions: It was concluded that, despite the differences in BT and MT in the two models of repeated sprints, the MT in both tests correlated well, suggesting that repeated sprint ability is a general quality and independent of changing direction. Moreover, both the glycolytic and neuromuscular demand did not differ between the two sprints models (AU)

Physiological and neuromuscular indices associated with sprint running performance.

The purpose of the study was to analyze the relationships among physiological and neuromuscular indices with the 200- and 400-m sprint running performance. Fourteen male sprinters performed the following tests: determination of 200- (P200) and 400-m (P400) running performance; determination of VO2max and the velocity associated at VO2max; squat jump (SJ) and countermovement jump (CMJ); and maximal accumulated oxygen deficit (MAOD). Significant correlations were observed between SJ (r = -0.53), CMJ (r = -0.69), and MAOD (r = -0.65) with P200. Countermovement jump (CMJ) and MAOD explained 70% of the P200. The MAOD was the only variable to correlate significantly with P400 (r = -0.56); VO2max and CMJ were also selected in the regression together and explained 79% of P400. The indicators of muscular power and anaerobic capacity are capable of explaining P200. In the 400 m, the performance was determined by indices of anaerobic capacity, in conjunction with the athletes' aerobic and muscular power.

Validity of two methods for estimation of vertical jump height.

The objectives of this study were (a) to determine the concurrent validity of the flight time (FT) and double integration of vertical reaction force (DIF) methods in the estimation of vertical jump height with the video method (VID) as reference; (b) to verify the degree of agreement among the 3 methods; (c) to propose regression equations to predict the jump height using the FT and DIF. Twenty healthy male and female nonathlete college students participated in this study. The experiment involved positioning a contact mat (CTM) on the force platform (FP), with a video camera 3 m from the FP and perpendicular to the sagittal plane of the subject being assessed. Each participant performed 15 countermovement jumps with 60-second intervals between the trials. Significant differences were found between the jump height obtained by VID and the results with FT (p ≤ 0.01) and DIF (p ≤ 0.01), showing that the methods are not valid. Additionally, the DIF showed a greater degree of agreement with the reference method than the FT did, and both presented a systematic error. From the linear regression test was determined the prediction equations with a high degree of linearity between the methods VID vs. DIF (R = 0.988) and VID vs. FT (R = 0.979). Therefore, the prediction equations suggested may allow coaches to measure the vertical jump performance of athletes by the FT and DIF, using a CTM or an FP, which represents more practical and viable approaches in the sports field; comparisons can then be made with the results of other athletes evaluated by VID.

Força de reação do solo em diferentes segmentos corporais de judocas na realização de “ukemis” em diferentes tipos de tatames / Ground reaction force proceeding from different corporal segments of the judo athlete in accomplishment of “ukemis” in different types of tatamis

Este estudo de cunho exploratório teve como objetivo medir, avaliar e comparar as forças de reação do solo transmitidas através dos diferentes tipos de tatames ao corpo do judoca. Foram testados sete tatames, seis sintéticos e um de palha, nos quais foram realizadas 210 quedas, sendo 10 quedas em cada segmento corporal (mão, quadril e pé), executadas por dois judocas. Como instrumento de medida utilizou-se uma plataforma de força OR6-5 AMTI. Para a coleta de dados, os tatames eram colocados sobre a plataforma, no qual eram realizadas as quedas. Os sinais foram captados em mV , transformados em N e normalizados pelo peso corporal do judoca. Os resultados demonstraram que as FRS mais altas foram encontradas no segmento corporal quadril. Ao se comparar as FRS, para a mão o tatame “C” foi o que apresentou a maior média e o tatame “E” a menor; no pé o tatame “B” apresentou a maior valor e o tatame “F” a menor. Conclui-se que as forças de impacto foram diferentes entre os tatames e entre os segmentos e tão altos quanto a modalidades esportivas que exigem saltos e provocam impactos verticais.

This study of exploratory characteristic had as aim to measure, evaluating and comparing the ground reaction forces transmitted through different types of tatamis at the judo practitioner body. Seven tatamis, synthetic six and one of straw had been tested, in which 210 falls had been carried through being 10 falls in each corporal segment (hand, hip and foot), executed for two judo practitioners. A force plate OR6-5 AMTI was used as measure instrument. For the data collection, the tatamis were placed on the platform, in which were carried through the falls. The signals had been caught in mV and transformed into N and normalized by the corporal weight of judo practitioner. The results had demonstrated that the FRS highest had been found in the corporal segment hip. When comparing the FRS for the hand the tatamis “C” presented the average greater and the tatamis “E” the minor; in foot the tatamis “B” presented the biggest value and tatamis “F” the minor. One concludes that the impact forces had been different between the tatamis and between the segments and so high as the sports modalities that demand jumps and cause vertical impacts.