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1.
跳远起跳肌肉专项能力生物力学研究   总被引：3，自引：0，他引：3  
王琨  魏文仪 《体育科学》2005,25(1):42-45
运用生物力学理论和实验研究方法 ,对跳远运动员起跳过程中起跳腿肌肉群表现出的专项能力特点进行研究。结果表明 ,髋关节伸肌群离心收缩能力对起跳十分重要 ;起跳表现出“前支撑蹬伸”特征 ;起跳过程中膝关节伸肌群的主动向心收缩能力对人体产生必要制动和适宜的腾起垂直速度具有重要意义 ;起跳初始阶段 (起跳过程 8%的时间里 )膝关节产生较大的屈肌力矩 ,即表现出膝关节屈肌群的主动收缩。  相似文献   

2.
Abstract

This study aimed to analyse whether increasing the eccentric overload (EO) during resistance training, in terms of range of motion and/or velocity using an electric-motor device, would induce different muscle adaptations than conventional flywheel-EO resistance training. Forty physically active university students (21.7?±?3.4 years) were randomly placed into one of the three training groups (EX1, EX2, FW) and a control group without training (n?=?10 per group). Participants in the training groups completed 12 sessions (4 sets of 7 repetitions) of iso-inertial single-leg squat training over 6 weeks for the dominant leg. Resistance was generated either by an electric-motor device at two different velocities for the eccentric phase; 100% (EX1) or 150% (EX2) of concentric speed, or by a conventional flywheel device (FW). Thigh lean tissue mass, unilateral leg press one-repetition maximum (1-RM), unilateral muscle power at different percentages of the 1-RM and bilateral/unilateral vertical jump were assessed before and after the 6-week training. There were significant (p?<?0.05–0.001) main effects of time in the 3 training groups, indicating increased thigh lean tissue mass (2.5–5.8%), 1-RM load (22.4–30.2%), vertical jump performance (9.1–32.9%) and muscle power (8.8–21.7%), without differences across experimental groups. Participants in the control group did not improve any of the variables measured. In addition, EX2 showed greater gains in eccentric average peak power during training than EX1 and FW (p?<?0.001). Despite the different EO offered, 6 weeks of resistance training using flywheel or electric-motor devices induced similar significant gains in muscle mass, strength, muscle power and vertical jump.  相似文献   

3.
Abstract

Plantar flexion and knee extension fatigue patterns elicited by 25 serial isometric contractions were assessed on eight female distance runners. Fiber type composition of the vastus lateralis and gastrocnemius muscles was examined by a needle biopsy technique. Two different isometric exercise regimens were administered: 10-sec contractions separated by 5-sec intertrial rest (10:5) designed to elicit a rapid rate of fatigue, and 10-sec contractions separated by 20-sec intertrial rest (10:20) designed to induce less fatigue. No fatigue pattern was found for the 10:20 regimen which was consistent with previous data on male distance runners but unlike male power athletes who did exhibit significant fatigue. Significant fatigue decrements were found for the 10:5 knee extension (55.7%) and plantar flexion (75.8%) conditions. Fiber type composition and fatigue decrements did not correlate. Knee extension and plantar flexion maximum strength correlated significantly with the amount of fatigue induced with r's of .82 and .83, respectively. For each separate muscle group, maximum isometric strength was a better predictor of fatigability than fiber type composition. Even though differences in maximal strength and muscle mass existed between knee extension and plantar flexion muscle groups, elicited fatigue curves were similar in pattern differing only in absolute level. High versus low strength classification analysis showed similar knee extension but dissimilar plantar flexion fatigue patterns. Results suggest that the role of fiber type composition, muscle mass, and maximum strength level as they influence local muscular fatigue patterns must be elucidated for each muscle group separately.  相似文献   

4.
跳远运动员专项成绩与专项身体素质相关关系的研究   总被引：1，自引：0，他引：1  
对我国 10名男子跳远运动员的专项成绩、专项身体素质以及下肢髋、膝和踝 3大关节等速屈伸肌力矩等指标进行测试。通过相关分析探讨了跳远运动员专项身体素质、下肢力量水平与专项成绩之间的关系 ,发现髋关节屈伸肌肌力、膝关节屈伸肌肌力和伸肌的离心肌力以及踝关节的跖屈肌力与跳远成绩相关  相似文献   

5.
ABSTRACT

Previous research suggests that landing mechanics may be affected by the mechanics of the preceding jump take-off. The purpose of the present study was to investigate whether jump take-off mechanics influence the subsequent landing mechanics. Female volleyball (n = 17) and ice hockey (n = 19) players performed maximal vertical jumps with forefoot and heel take-off strategies. During forefoot and heel jumps, participants were instructed to shift their weight to their forefoot or heel, respectively, and push through this portion of the foot throughout the jump. Jump mechanics were examined using 3D motion analysis, where lower extremity net joint moment (NJM) work, NJM, and segment angles were compared between forefoot and heel jumps using multivariate ANOVA. During jump take-off, participants performed more positive ankle plantar flexor and knee extensor NJM work in forefoot compared to heel jumps (P < 0.05). From initial foot contact to foot flat, participants performed more negative ankle plantar flexor and hip extensor NJM work during heel compared to forefoot jumps (P < 0.05). The present results demonstrate that using a heel take-off strategy results in a different distribution of lower extremity NJM work and NJM during landing compared to landings following forefoot jumps.  相似文献   

6.
Abstract

In recent years, a method of plyometrics (exercises that cause a rapid lengthening of a muscle prior to contraction) called depth jumping has become a part of the training routine of many athletes. Two experiments are described in which the effectiveness of the exercises is examined. In Experiment 1, undergraduate students in beginning weight training classes trained with three different jumping programs: (1) maximum vertical jumps, (2) 0.3 m depth jumps, and (3) 0.75 m and 1.10 m depth jumps. In addition, all groups also lifted weights. In Experiment 2, a weight training class and the volleyball team at Brigham Young University-Hawaii were divided into two groups. One group lifted weights and performed 0.75 and 1.10 m depth jumps. The other group only lifted weights. In Experiment 1, the three training programs resulted in increases in one repetition maximum (1 RM) squat strength, isometric knee extension strength, and in vertical jump; however, there were no significant differences between treatments. In Experiment 2, all groups made significant increases in vertical jump, except the group of weight lifters, who did no jumping. It was concluded that depth jumps are effective but not more effective than a regular jumping routine.  相似文献   

7.
This study analysed the modulation of jump performance, vertical stiffness as well as joint and intralimb coordination throughout a 30-s vertical jump test. Twenty male athletes performed the test on a force plate while undergoing kinematic analysis. Jump height, power output, ground contact time, vertical stiffness, maximum knee and hip flexion angles, and coordination by continuous relative phase (CRP) were analysed. Analysis of variance was used to compare variables within deciles, and t-tests were used to compare CRP data between the initial and final jumps. Results showed reduction in jump height, power output, and vertical stiffness, with an increase in contact time found during the test. Maximum knee and hip flexion angles declined, but hip angle decreased earlier (10–20% of the test) than knee angle (90–100%). No changes were observed in CRP for thigh–leg coupling when comparing initial and final jumps, but the trunk–thigh coupling was more in-phase near the end of the test. We conclude that fatigue causes reduction in jump performance, as well as changes in stiffness and joint angles. Furthermore, changes in intralimb coordination appear at the last 10% of the test, suggesting a neuromotor mechanism to counterbalance the loss of muscle strength.  相似文献   

8.
Abstract

We tested the hypothesis that the performance of rapid movements represents body size-independent indices of muscle power. Physical education students (n = 159) were tested on various vertical jump (jump height and average power calculated from the ground reaction force) and muscle strength tests. When non-normalized data were used, a principal components analysis revealed a complex and inconsistent structure where jump height and muscle power loaded different components, while muscle strength and power partially overlapped. When the indices of muscle strength and power were properly normalized for body size, a simple and consistent structure of principal components supported the hypothesis. Specifically, the recorded height and muscle power calculated from the same jumps loaded the same components, separately for the jumps predominantly based on concentric actions and jumps based on a rapid stretch – shortening cycle of the leg extensors. The finding that the performance of rapid movements assesses the same physical ability as properly normalized tests of muscle power could be important for designing and interpreting the results of batteries of physical performance tests, as well as for understanding some basic principles of human movement performance.  相似文献   

9.
Abstract

Twenty-seven male subjects performed two 5-min bouts of rhythmic, isometric elbow flexion and two similar bouts of knee extension at a rate of 30 maximal contractions per min. Exponential analyses revealed that the pattern of fatigue for each limb followed a single component curve of the form: Yt = a0e ?Kot + c. An analysis of variance comparing the results from the two limbs revealed that (a) the strength scores for the leg were significantly (p < .05) higher than those for the arm throughout the exercise bouts; (b) both limbs experienced a significant strength decrement; and (c) there was significant interaction between trials and limbs. It appeared that the greater loss of strength by the knee extensors was reponsible for this interaction. It was concluded that during a rhythmic, all-out task, the rates of fatigue experienced by the two muscle groups tend to differ, with the elbow flexors fatiguing more rapidly initially but reaching a plateau at a relatively higher level than the knee extensors.  相似文献   

10.
Abstract

The aim of this study was to test the correlation between knee-to-hip flexion ratio during a single leg landing task and hip and knee strength, and ankle range of motion. Twenty-four male participants from a professional soccer team performed a continuous single leg jump-landing test during 10s, while lower limb kinematics data were collected using a motion analysis system. After biomechanical testing, maximal isometric hip (abduction, extension, external rotation), knee extension and flexion strength were measured. Maximum ankle dorsiflexion range of motion was assessed statically using the weight bearing lunge test. Pearson correlation coefficients were calculated to determine the associations between the predictor variables (knee and hip strength, and ankle ROM) and the main outcome measure (knee-to-hip flexion ratio). Correlation between knee-to-hip flexion ratio and hip abductors strength was significant (r = ?0.47; p = 0.019). No other significant correlations were observed among the variables (p > 0.05). These results demonstrated that a lower hip abductors strength in male soccer players was correlated with a high knee-to-hip flexion ratio during landing from a single leg jump, potentially increasing knee overload by decreasing energy absorption at the hip. The results provide a novel proposal for the functioning of hip muscles to control knee overload.  相似文献   

11.
Abstract

The purpose of this study was to examine the strength-decrement fatigue effects in 14 muscle groups of the trunk and lower extremities resulting from a sub-maximal treadmill run at seven miles per hour for a period of ten minutes on a horizontal plane. Only two muscle groups, the hip outward rotators and the trunk flexors, were fatigued sufficiently to cause a significant strength decrement; a third muscle group, the knee flexors, had a loss in mean strength which approached the .05 level of confidence.  相似文献   

12.
Abstract

The aim of the present study was to examine the relationships between muscle cross-sectional area (CSA) and muscular strength in terms of knee extension and flexion, hip extension and flexion, and hip abduction and adduction among well-trained soccer players. Fourteen university soccer players participated in the study, who had previously been divided into two groups based on ability (Group A: above-average ability; Group B: average ability). Maximal isokinetic and concentric muscular strength was measured in knee extension/flexion, hip extension/flexion and hip abduction/adduction using an isokinetic dynamometer at 1.57 and 4.19 rad·s?1 (3.14 rad·s?1) in both the dominant and non-dominant leg. The CSAs of the thigh, gluteus muscles and iliopsoas muscles were calculated based on magnetic resonance imaging. There was no significant difference between the two groups in muscle CSA and isokinetic strength. Although there were some statistically significant differences between the dominant and non-dominant leg in terms of CSA and strength (P<0.05–0.01), these were small and negligible. Apart from a non-significant relationship between the CSAs of the adductor muscles and hip adductor strength (r<0.26, n.s.), the CSA of the other muscle groups correlated with maximal isokinetic strength (r=0.38–0.64, P<0.05). These results suggest that no difference in muscle characteristics (in terms of muscle CSA and strength) was apparent among well-trained soccer players, even between the dominant and non-dominant leg. There is also a case that the anatomical function of a single (or group of) muscle(s) may not be reflected by the strength—CSA relationship depending on the movements (such as hip adduction-adductor muscle CSA). Thus, further studies are required to develop methods to assess neuromuscular function in relation to muscle morphology among soccer players.  相似文献   

13.
目的：探讨中老年女性增龄性肌力流失的规律特征。方法：以85名中老年女性为实验组，按年龄分为3个年龄组，以29名青年女性为对照组，运用全身型双能X线骨密度仪、Con-Trex等速肌力测试系统进行全身肌肉质量，下肢髋、膝、踝关节屈伸等长与60°/s的等速肌力测试。结论：50年龄段的中年女性已表现出明显的肌肉质量流失、且在70岁前仍表现为以下肢肌肉质量流失为主的局部性特征。中老年女性下肢肌肉力量流失的增龄性特征表现为髋关节的肌肉力量流失最早表现，下肢肌肉收缩力量呈现快速流失的“拐点”约在60岁年龄段，且有肌肉的动态收缩力量的流失先于等长收缩力量的年龄特征。下肢三关节等长收缩力量流失呈现“髋-膝-踝”模式，60°/s的等速力量约在60岁后呈现“膝-踝-髋”模式。结论：老年女性膝关节屈肌较之伸肌可能有着更高的肌力流失速率。肌肉质量与力量流失的关系方面表现出力量流失先于质量流失的特征。  相似文献   

14.
Abstract

Nineteen college men and women (aged 18–23 yrs, × = 21.1) were studied to ascertain the force-time components of a rapid maximal voluntary isometric contraction (MVC) for ankle dorsiflexors, knee extensors, elbow flexors, wrist flexors and hand grip. Standardized isometric strength testing protocol was used. After a practice period subjects were instructed to make an MVC without jerking and as quickly as possible, for each of the muscle actions noted above. Force readings were taken from a load cell assembly through an analogue-to-digital converter and analyzed to yield time values for MVC, 3/4 MVC, 1/2 MVC, and 1/4 MVC. The results indicated significant differences (p < .01) between the responses of the men and women, with the women reaching full MVC more rapidly than the men. Also, there were significant differences among the five muscle groups tested, with the wrist flexor muscle group developing MVC most quickly, while the knee extensors took the longest time to full MVC. Based upon these data it may be concluded that the time to full MVC differs between men and women, and also that the time to full MVC differs among the five muscle groups tested in this experiment.  相似文献   

15.
Abstract

This study was to investigate the effect of increased muscle strength on the duration of the triceps surae reflex time. Subjects were 60 students within the age range of 18 to 20 years. The subjects were divided into two groups of equal size—a control and an experimental group. The experimental group performed isometric and isotonic plantar flexor muscle resistance exercises for 40 min. twice a week for a period of 6 weeks. The subjects were tested for plantar flexor static strength and triceps surae reflex time at approximately the same time of day prior to, and at the termination of, the training period. For the experimental group, the statistical analysis revealed a significant decrease in the triceps surae reflex time following strength training. The results of this study appear to warrant the conclusion that an increase in static strength through training has a significant shortening effect upon the triceps surae reflex time.  相似文献   

16.
采用等速测试和平衡测试方法,对我国优秀自由式滑雪空中技巧女子运动员的髋关节、膝关节屈肌力和伸肌力以及4种站姿下的静态平衡能力特征进行研究。结果表明髋关节右侧屈伸肌力、屈伸肌力比、平均功率值稍大于左侧屈肌力量,膝关节伸肌左、右侧单位体重峰力矩和左、右侧平均功率4个指标数值均大于屈肌,在60°/s（慢速）和240°/s（快速）不同的测试速度下,单位体重屈伸峰力矩、屈伸平均功率、屈伸肌力、平均功率随着测试速度的增加出现了显著性差异;正常双脚站立的平衡性大于单脚站立的平衡性。建议合理控制体重及均衡的训练肌肉力量,在适度提高运动速度的情况下,加强下肢伸肌力量的训练,为运动员进行针对性的力量训练、训练后肌肉效果的评价、运动员选材提供科学依据及有价值的理论参考。  相似文献   

17.
研究目的：探究拖重物跑训练手段对短跑运动员的身体素质、途中跑阶段的技术特征及下肢环节肌肉力量的影响，深入认识其对短跑途中跑技术和专项力量的作用机制。研究方法：对14名男子二级左右水平短跑运动员进行为期8周每周3次6%~10% BM负荷的拖重物跑训练，采用高速摄像分析法、等动肌力测试法分析运动员身体素质；支撑阶段髋、膝、踝关节运动学参数和下肢各环节肌肉力量实验前后的变化情况。结果：（1）实验后运动员30m、60m、立定跳远、立定三级跳远等身体素质及专项成绩显著提高；（2）步长、重心水平速度显著性提高，两大腿剪绞平均速度提高、单步时间减少；支撑阶段最小膝、踝角显著降低，角速度提高；（3）髋、膝关节伸/屈肌群PT/BW、AP除膝关节60°/sPT/BW值未见统计学意义，其余各角速度下PT/BW、AP均呈显著性差异，踝关节跖屈肌群各角速度下PT/BW值显著提高，跖屈肌群60°/s速度下AP提高，背屈肌群AP略降低。结论：适宜负荷的拖重物跑训练可显著改善短跑运动员运动素质、提高运动成绩；有利于提高髋关节剪绞-制动力量，使膝、踝关节处于低位超等长"屈蹬"状态；提高了髋、膝关节屈伸肌群快速主动收缩能力及踝关节跖屈肌群退让性快速收缩能力。  相似文献   

18.
Purpose: This study explored the effect of whole-body vibration (WBV) using accelerations of 2.56 g to 7.68 g on lower-body detraining. Methods: All participants (N = 20) were trained using a lower-body resistance-training program for 30 min twice per week from Week 0 to Week 6. At the end of the program, they were randomly assigned to a control group that performed no further training or a WBV group that performed a progressive static WBV program. Data for the 5-repetition-maximum (5RM) squat and extensors and flexors of the knee and ankle were collected at Weeks 0, 6, 8, 10, and 12 for all participants. Results: Two-way (condition vs. time) analysis of variance revealed that although the WBV group maintained strength in the 5RM from Week 6 through Week 8 and the control group had a lower 5RM in Week 8 from Week 6, no differences in the 5RM squat existed between the groups at Week 8. Two-way factorial multivariate analysis of variance revealed no differences between the groups at any of the time for torque of knee flexion, dorsiflexion, or plantar flexion. Conclusion: Static WBV of 2.56 g to 7.68 g did not attenuate detraining of the flexors and extensors of the knee and ankle.  相似文献   

19.
Abstract

Fifteen highly skilled sprinters were filmed while running at maximum velocity. The results were digitized and computer processed with interest focused on the muscle moments generated about the hip, knee, and ankle of the ground leg. Muscle activity about the hip consisted of extensor (concentric) dominance from foot descent, through foot strike, and into mid-support. Muscle dominance shifted to the hip flexors (eccentric) during mid-support and continued through takeoff. Muscle dominance at the knee demonstrated a pattern of flexor (eccentric, then concentric) dominance from foot descent through foot strike and into mid-support. Knee extensors (eccentric, then concentric) then achieved dominance through takeoff. During the later stages of takeoff, the dominance decreased or reversed briefly to flexor (eccentric) activity prior to a period of minimal activity following the toe-off position. From a period of minimal activity prior and subsequent to ground contact, the plantar flexors (eccentric, then concentric) of the foot were dominant throughout the ground phase. Qualitatively, the unexpected knee flexor dominance during foot strike was generated to limit the braking action created during this portion of ground contact. The unanticipated hip flexor dominance during takeoff served to rotate the upper body forward and into the approaching air phase. In addition, both of these actions allowed efficient use of the two-joint muscles of the leg during the critical phases of ground contact. Finally, the minimizing or reversing of the knee extensor dominance during the later stages of takeoff served to protect the joint from injury. Quantitatively, the magnitude of hip extensor/knee flexor activity during foot strike was significantly related (r = .70, p = .01) to the prior occurrences of related leg injury in the subjects.  相似文献   

20.
Abstract

This study aimed to examine the effects of application of kinaesthetic tapes on plantarflexor muscle performance. We hypothesised that taping of the triceps surae muscle would improve plantarflexor muscle strength and endurance with no significant effect on drop jump performance. Using a repeated-measures design, all performance measures were obtained in 24 volunteers on two separate occasions: without tapes and after application of kinaesthetic tapes. Performance tests included measurements of isometric plantarflexor muscle strength and the associated electromyographic activity of the gastrocnemius muscle, an isokinetic fatigue resistance test (30 contractions at 180° · s?1) and assessments of drop jump performance. The taping-intervention was associated with an increase in gastrocnemius electromyographic activity. However, significant increases in isometric strength were only found at fully dorsiflexed ankle positions (+12% at ?20°). Strength gains were negatively correlated to baseline strength (r = ?.58). The intervention did not affect the results of the isokinetic fatigue and drop jump tests. The application of kinaesthetic tapes over the triceps surae muscle promotes an increase in isometric strength and gastrocnemius muscle activity. Our data suggest that these effects are joint-angle dependent and more prominent in weaker individuals. By contrast, the taping-intervention improves neither drop jump performance nor muscular endurance.  相似文献   

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