近十年中国网球竞技实力提升的实证分析     

刘巍  付甲 《广州体育学院学报》2013,(6):73-76

运用文献资料法、案例分析法等,分析中国网球近十年来在国际大赛中所取得的成绩和名次的上升 。国家网球竞技实力的提升具体表现在几方面：全面参与世界大赛,网球实力初具国际竞争力;积极举办 国际顶级网球赛事,赛事国际影响力日益增强;加强对外合作交流,网球国际地位显著提升。中国网球竞 技实力提升的经验在于：科学把握项目规律和改革方向;坚持训练和管理的不断创新;坚持训练、科研、 教育三结合;坚持统筹兼顾和谐发展;坚持理论与实践的有效转化。  相似文献   

Effects of 12 weeks of dynamic strength training with local vibration     

《European Journal of Sport Science》2013,13(7):695-702

Abstract

The purpose of this study was to investigate the chronic effects of dynamic strength training (ST) with local vibration on the maximum strength of elbow flexor muscles. Twenty healthy male untrained volunteers were divided randomly into the following two groups: the conventional training group (CTG) or the vibration training group (VTG). Both groups performed ST for 12 weeks, three times a week. The ST protocol included four sets of 8–10 repetition maximums (RMs) of unilateral elbow flexion exercise. The VTG performed this training protocol with local vibration at a frequency of 30 Hz and amplitude of 6 mm. The mean values of the one repetition maximum (1RM) tests for both groups increased significantly from the pretest week to the fourth week and from the fourth week to the eighth week (CTG: mean 19.02, s = 7.88%, p = 0.01; mean 10.50, s = 6.86%, p = 0.019, respectively; VTG: mean 16.02, s = 8.30%, p = 0.017; mean 12.55, s = 8.76%, p = 0.019, respectively). The increases in the maximal voluntary contraction (MVC) tests were also statistically significant from the pretest week to the fourth week and from the fourth week to the eighth week (CTG: mean 12.32, s = 8.33%, p = 0.004; mean 9.95, s = 5.32%, p = 0.006, respectively; VTG: mean 10.16, s = 11.71%, p = 0.003; mean 10.36, s = 2.96%, p = 0.01, respectively). There was no significant difference between the 1RM and MVC test results in the eighth and twelfth weeks in either group. No significant differences were observed between the groups (p < 0.05). In conclusion, the application of local vibration does not change the chronic effects of dynamic ST in untrained individuals.  相似文献   

Changes in leg strength 8 and 32 h after endurance exercise     

Michael Leveritt  Helen MacLaughlin  Peter J. Abernethy 《Journal of sports sciences》2013,31(11):865-871

The aim of this study was to determine the effects of a single bout of endurance exercise on subsequent strength performance. Eight males with a long history of resistance training performed isokinetic, isometric and isotonic leg extension strength tests 8 and 32 h after 50 min of cycle ergometry at 70-110% of critical power. The participants also completed a control condition in which no cycling was performed. Plasma lactate and ammonia were measured before and immediately after each strength test. Isokinetic, isometric and isotonic leg extension torques were not significantly different 8 or 32 h after endurance exercise compared with the control condition ( P > 0.05). A large (50.3%), but not statistically significant, increase in plasma ammonia was evident during the strength tests performed 8 h after endurance exercise, while a significant ( P ? 0.05) increase in ammonia was also seen 32 h after endurance exercise. No significant changes in plasma ammonia were evident in the control condition. Our results suggest that leg extension strength was not compromised by an earlier bout of endurance cycling. However, metabolic activity during the strength tests might have been altered by the preceding bout of endurance exercise.  相似文献   

Neuromuscular variables affecting the magnitude of force loss after eccentric exercise     

STEPHEN SAYERS  CHRISTOPHER KNIGHT  PRISCILLA CLARKSON 《Journal of sports sciences》2013,31(5):403-410

The aim of this study was to examine neuromuscular variables contributing to differences in force loss after participants were exposed to the same relative bout of eccentric exercise. Thirty-six males performed 50 maximal eccentric contractions of the elbow flexors and were stratified into high responders (n?=?10) and low responders (n?=?10) based on force loss 36 h after exercise. Maximal voluntary isometric contractions (MVCs) and electromyography (EMG) were measured at baseline and 36 h after exercise. During eccentric exercise, mean peak torque, mean end-range torque from the final 25% of each trial and total angular impulse were computed over 25 contractions in each of two bouts. The slope of the change in these values for each 25 eccentric contractions was calculated for each participant using linear regression. At baseline, MVC was not different between groups (low responders: 97.0?±?9.6 N?·?m; high responders: 82.7?±?6.4 N?·?m; P?=?0.08). High responders demonstrated a 68% (range 62-78%) reduction in MVC and low responders a 39% (29-48%) reduction after exercise. Peak torque, end-range torque and total angular impulse were 13%, 40% and 33% higher, respectively, in the low than in the high responders (peak torque: P?=?0.0002; end-range torque: P?<?0.0001; total angular impulse: P?<?0.001). The rate of decline in peak torque slope was greater in high than in low responders (P?=?0.044). In conclusion, lower peak torque, end-range torque and total angular impulse during eccentric contractions and a greater peak torque slope may identify high responders to eccentric exercise.  相似文献   

The effects of ACL injury on quadriceps and hamstring torque,work and power     

Danny M. Pincivero  Brandan M. Heller  Su-I Hou 《Journal of sports sciences》2013,31(9):689-696

The aim of this study was to assess isokinetic torque, work and power between non-injured, ACL (anterior cruciate ligament)-deficient and ACL-reconstructed individuals. Ten healthy, non-injured individuals, seven unilateral ACL-deficient individuals and six unilateral ACL-reconstructed individuals were assessed for isokinetic quadriceps and hamstring strength at 1.05 and 3.14 rad ·s -1 . Peak torque, total work, average power and the ratio of peak torque to body mass were computed for both velocities. Peak torque was also corrected for body mass, using allometric modelling. The non-injured individuals showed significantly greater quadriceps peak torque to body mass ratios than the ACL-deficient and ACL-reconstructed individuals at both velocities, and greater hamstring peak torque to body mass ratios than the ACL-deficient group at 3.14 rad · s -1 ( P ? 0.05). The ACL-deficient individuals displayed greater quadriceps and hamstring peak torque, total work and average power than the non-injured individuals at 1.05 rad · s -1 ( P ? 0.05). The ACL-deficient individuals also displayed significantly greater peak torque, total work and average power than the ACL-reconstructed individuals for the quadriceps at both velocities ( P ? 0.05). The ACL-deficient individuals demonstrated greater hamstring peak torque and total work than the non-injured individuals at both velocities ( P ? 0.05). The allometrically modelled peak torques at both isokinetic velocities demonstrated that the quadriceps muscle values were significantly higher in the non-involved than the involved limb. The hamstring peak torques corrected for body mass were significantly higher in the non-involved than the involved limb only at 1.05 rad ·s -1 . The main finding from the present study is that isokinetic measures in ratio-scaled or absolute units yield a different outcome and, hence, interpretation compared with the allometric approach.  相似文献   

Effects of regular training at the same time of day on diurnal fluctuations in muscular performance     

Nizar Souissi  Antoine Gauthier  Bruno Sesboüé  Jacques Larue  Damien Davenne 《Journal of sports sciences》2013,31(11):929-937

The aim of this study was to determine whether there is an effect of time of day on the adaptation to strength training at maximal effort. Fourteen participants took part in this experiment. Their peak anaerobic power (Wingate anaerobic test) and peak knee extension torque at six angular velocities (1.05, 2.10, 3.14, 4.19, 5.24 and 6.29 rad · s -1 ) were recorded in the morning (between 07:00 and 08:00 h) and in the evening (between 17:00 and 18:00 h) just before and 2 weeks after a 6 week course of regular training. Seven of them trained only in the morning and seven only in the evening. Multivariate analysis of variance revealed a significant group 2 pre-/post-training 2 time of day interaction effect for peak torque and peak anaerobic power. Before training, in both groups, peak torque and peak anaerobic power were significantly higher in the evening than in the morning. After training, there was no significant difference in peak torque and peak anaerobic power between the morning and the evening for the morning training group. In contrast, in the evening training group, peak torque and peak anaerobic power were higher in the evening than in the morning. As a result of training, both peak torque and peak anaerobic power increased from their initial values as expected. The morning training group improved their peak anaerobic power significantly in the morning and in the evening, the absolute increase being larger in the morning than in the evening. The evening training group did not improve their peak anaerobic power in the morning, whereas it improved significantly in the evening. Although peak torque was significantly improved by training in the morning and evening in both groups, the absolute increase was greater in the morning than in the evening in the morning training group, whereas the opposite was the case for the evening training group. These results suggest that training twice a week at a specific hour increases the peak torque and the peak anaerobic power specifically at this hour and demonstrates that there is a temporal specificity to strength training.  相似文献   

Biceps femoris long head muscle fascicle length does not differ between sexes     

Fearghal P. Behan  Rachael Moody  Tejal Sarika Patel  Edward Lattimore  Thomas M. Maden-Wilkinson  Thomas G. Balshaw 《Journal of sports sciences》2013,31(21):2452-2458

ABSTRACT

Hamstring strain injury (HSI) rates are higher for males vs. females. This cross-sectional study investigated if inherent differences in biceps femoris long head (BF_LH) fascicle length (Lf) exist between recreationally active males and females (i.e., individuals without specific training practice history). Twenty-four young healthy participants (12 males; 12 females) had their BF_LH muscle architecture (Lf, pennation angle [θp], and muscle thickness [MT]) measured using B-mode ultrasonography. Eccentric and isometric knee flexion strength were also assessed. BF_LH Lf did not differ between sexes when expressed in absolute terms (males, 81.5 ± 14.7 mm; females, 73.6 ± 15.9 mm, P = 0.220, effect size (ES) = 0.52) or relative to femur length (0.140 ≤ P ≤ 0.220, ES = 0.63). Similarly, BF_LH θp did not differ between sexes (P = 0.650) but BF_LH MT was 18.9% larger for males vs. females (P = 0.024, ES = 0.99). Isometric and eccentric knee flexion strength was greater for males vs. females in absolute terms ([both] P < 0.001, 2.00 ≤ ES ≤ 2.27) and relative to body mass ([both] P < 0.001, 1.93 ≤ ES ≤ 2.13). In conclusion, factors other than BF_LH Lf seem likely to be implicated in higher male vs. female HSI rates.  相似文献   

The effect of knee angle on the external validity of isometric measures of lower body neuromuscular function     

Samuele Marcora  Marilyn K. Miller 《Journal of sports sciences》2013,31(5):313-319

The aim of this study was to evaluate the effect of varying knee angle (120° and 90°) on the external validity of an isometric leg press test with reference to vertical jump performance. Isometric peak force (PF 120 and PF 90 ), rate of force development (RFD 120 and RFD 90 ), and maximum height reached with a squat jump and counter-movement jump were measured in 14 males. Although RFD 120 was significantly correlated with squat jump and counter-movement jump performance ( r = 0.71 and 0.69), and the correlations with PF 120 approached statistical significance ( r = 0.53 and 0.50), neither PF 90 nor RFD 90 was significantly related to vertical jump performance. Furthermore, although both RFD 120 and PF 120 were significantly different between the best five and the worst five jumpers, RFD 90 and PF 90 did not differentiate between individuals' vertical jump performance. We conclude that the choice of joint angle affects the external validity of isometric strength testing. Based on our results, we recommend accurate control of biomechanical specificity and assessment at different angles to find the position at which isometric strength testing is most comfortable.  相似文献   

对高校体操教学中力量素质训练的认识     

贾磊  刘健 《山东教育学院学报》2009,24(4):104-105

体操是高校体育专业的一门主干必修课程,体操作为一项体育与艺术有机结合的综合性竞技项目,展示了她独特魅力。力量素质是进行体操教学和训练的基础。文章采用文献资料法,对体操教学中力量素质训练进行综述、分析和探讨并提出力量素质训练的合理化建议,以期对大学生体操教学和训练提供帮助。  相似文献   

回弹法在混凝土质量管理中的应用     

何祺义  罗永滨 《科技广场》2009,(1)

回弹值换算成混凝土强度可通过对比试验建立实测的测强曲线来进行换算.本文对专用测强曲线的建立方法进行了探讨,得到了某桥梁工程混凝土强度推定值计算公式.  相似文献