共查询到20条相似文献，搜索用时 625 毫秒
1.
《European Journal of Sport Science》2013,13(8):823-829
AbstractNon-local muscle fatigue has been demonstrated with unilateral activities, where fatiguing one limb alters opposite limb forces. Fewer studies have examined if non-local fatigue occurs with unrelated muscles. The purpose of this study was to investigate if knee extensors fatigue alters elbow flexors force and electromyography (EMG) activity. Eighteen males completed a control and fatiguing session (randomised). Blood lactate was initially sampled followed by three maximal voluntary contractions (MVC) with the elbow flexors and two with the knee extensors. Thereafter, subjects either sat (control) or performed five sets of bilateral dynamic knee extensions to exhaustion using a load equal to the dominant limb MVC (1-min rest between sets). Immediately afterwards, subjects were assessed for blood lactate and unilateral knee extensors MVC, and after 1 min performed a single unilateral elbow flexor MVC. Two minutes later, subjects performed 12 unilateral elbow flexor MVCs (5 s contraction/10 s rest) followed by a third blood lactate test. Compared to control, knee extensor force dropped by 35% (p < 0.001; ES = 1.6) and blood lactate increased by 18% (p < 0.001; ES = 2.8). Elbow flexor forces were lower after the fatiguing protocol only during the last five MVCs (p < 0.05; ES = ～0.58; ～5%). No changes occurred between conditions in EMG. Elbow flexor forces significantly decreased after knee extensors fatigue. The effect was revealed during the later stages of the repeated MVCs protocol, demonstrating that non-local fatigue may have a stronger effect on repeated rather than on single attempts of maximal force production. 相似文献
2.
The aim of this study was to examine the effect of leg muscle fatigue on the kinetics and kinematics of the instep football kick. Fatigue was induced by repeated, loaded knee extension (40% body weight) and flexion (50% body weight) motions on a weight-training machine until exhaustion. The kicking motions of seven male players were captured three-dimensionally at 500 Hz before and immediately after the fatigue protocol. The significantly slower ball velocity observed in the fatigue condition was due to both reduced lower leg swing speed and poorer ball contact. The reduced leg swing speed, represented by a slower toe linear velocity immediately before ball impact and slower peak lower leg angular velocity, was most likely due to a significantly reduced resultant joint moment and motion-dependent interactive moment during kicking. These results suggest that the specific muscle fatigue induced in the present study not only diminished the ability to generate force, but also disturbed the effective action of the interactive moment leading to poorer inter-segmental coordination during kicking. Moreover, fatigue obscured the eccentric action of the knee flexors immediately before ball impact. This might increase the susceptibility to injury. 相似文献
3.
王艳春 《西安体育学院学报》2012,29(4):497-500
目的研究篮球运动员下肢膝关节肌力在疲劳状态下的变化,以便加强容易疲劳肌群的力量训练。方法研究选择高水平女篮11名运动员为受试者,采用等速肌力测试系统测定膝关节正常状态和疲劳状态下的屈伸肌力及做功情况。结果篮球运动员在运动中更容易导致屈肌产生疲劳,左侧下肢膝关节屈肌的总功力量存在明显差异性。结论篮球运动更容易引起膝关节屈肌产生疲劳,加强屈肌的肌肉力量训练对提高篮球运动员专项力量将有很大帮助。 相似文献
4.
目的：为了观察我国自由式滑雪空中技巧队男女运动员下肢膝关节屈伸肌群力量特点,发现目前下肢力量训练中存在的问题,以便为力量训练提供参考依据。方法：使用美国BIODEX公司生产的biodex system4等动测试系统对自由式滑雪空中技巧队男女运动员（男5名,女6名）的下肢膝关节屈伸肌群进行向心收缩的等动测试,测试速度分别为60°/s和180°/s。结果：男女运动员伸肌群的相对峰值力矩和相对平均功率都要显著高于屈肌群（P<0.01）。相对峰值力矩随着测试速度的增加而显著减小（P<0.01）,相对平均功率随测试速度的增加而显著增加（P<0.01）。男女运动员下肢屈伸肌比平均在50%～65%之间,并且随着测试速度的增加屈伸肌比显著增加（P<0.05）。在同一速度下,男女运动员伸肌峰值力矩出现的角度要显著大于屈肌（P<0.01）,但是在不同速度下,男女运动员伸肌峰值力矩出现的角度表现出不同的变化。随着测试速度的增加,屈伸肌群峰值力矩出现的时间显著变短（P<0.01）,并且同一速度下,屈肌群峰值力矩出现的时间要短于伸肌群（P<0.05）。左右腿膝关节屈伸肌群相对峰值力矩、相对平均功率、屈伸肌比等指标没有差异（P>0.05）。结论：了解到目前我国自由式滑雪空中技巧队男女运动员下肢肌肉的力量特点,其中男女运动员下肢膝关节屈伸肌比（H/Q）较低,应该注重发展股后肌群的力量,以提升屈伸肌比值。左右腿肌肉力量发展比较均衡。 相似文献
5.
Abstract In this study, we investigated the effect of eccentric exercise on position sense and reaction angle of the elbow and knee flexors. Twelve males underwent two eccentric exercise sessions involving a randomized crossover design. In the first session participants used their elbow flexors and in the other session their knee flexors. Muscle damage indices, position sense, and joint reaction angle to release of the elbow and knee flexors were measured before, immediately after, and up to 7 days after exercise. Exercise induced greater muscle damage in the elbow flexors than knee flexors. Exercise disturbed position sense of the elbow and knee joint. For both limbs, the participants adopted a more extended position than the reference angle. The elbow and knee joint reaction angles to release increased after exercise for both the elbow and knee flexors. The disturbances in position sense and reaction angle after exercise were greater in the elbow flexors than knee flexors. The elbow flexors remained more accurate and faster than the knee flexors at all time points. These results may be explained by the higher density of muscle spindles and the lower innervation ratio of the elbow flexors compared with the knee flexors, as well as the fact that the arms are more accustomed than the legs to perform fast and accurate movements. 相似文献
6.
目的:研究优秀乒乓球运动员和普通在校大学生肘关节拮抗肌活动在等动屈伸过程中的差异。方法:以8名优秀乒乓球运动员和8名普通高校大学生为研究对象,利用Biodex等动测试仪和Noraxon表面肌电仪记录上肢肘关节等动屈伸过程中作为拮抗肌的肱二头肌和肱三头肌的力量特征和表面肌电信号特征。肘关节伸肌和屈肌分别在最大等长收缩、15°/s、30°/s、60°/s、120°/s、180°/s、240°/s条件下进行3次最大等动离心屈伸运动。以标准化的均方根振幅(RMS)和标准化的峰值力矩作为评价指标。结果:对于大学生和优秀乒乓球运动员来说,随着肘关节速度的增加,两组受试者的屈伸肌力矩都呈下降趋势,大学生表现为速度大于60°/s时伸肌力矩大于屈肌力矩(P<0.05),优秀乒乓球运动员表现为伸肌力矩低于屈肌力矩,但没有统计学差别(P>0.05)。大学生和优秀乒乓球运动员都表现为在向心收缩时不同速度下随着主动肌力矩下降,拮抗肌激活水平表现为逐渐增高,且所有线性拟合系数r2>0.7。优秀乒乓球运动员拮抗肌肱三头肌的激活水平(在MVC时:10.1%±5.2%,240°/s时:15.1%±6.6%)要显著低于普通高校大学生(MVC时:29.3%±8.8%,240°/s时:38.0%±15.1%)。而作为拮抗肌的肱二头肌激活水平在普通大学生和优秀乒乓球运动员之间没有统计学差异(P>0.05)。优秀乒乓球运动员拮抗肌/主动肌肌电活动比要显著低于普通大学生(P<0.05)。结论:与普通大学生相比,优秀乒乓球运动员肘关节拮抗肌肱三头肌的激活水平要更低,这可能是优秀乒乓球运动员对肘关节周围肌肉进行长期训练的结果。而两者拮抗肌肱二头肌激活水平没有统计学差异,其原因可能是由于两者在日常活动中肱二头肌作为拮抗肌经常为了克服地心引力受到同样的刺激造成的。 相似文献
7.
George A. Ordway Jay T. Kearney G. Alan Stull 《Research quarterly for exercise and sport》2013,84(4):734-740
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
8.
目的:探讨不同快速降体重量对肌肉功能的影响;方法:以12名健康男生为实验对象,测定脱水前(0%bw l)、桑拿脱水快速降体重2%(2%bw l)、桑拿脱水快速降体重4%(4%bw l)这3种不同体重状态下最大等速肌力、等速肌耐力与无氧作功能力;在测定无氧作功能力时,结合运用主观用力程度等级评价量表(RPE),对肌肉功能进行系统评价;结果:1)2%bw l和4%bw l对肌肉的最大等速力量均没有削弱作用;2%bw l后,屈肘肌群的最大等速肌力反而增大。2)2%bw l对屈、伸肘肌群以及屈、伸膝肌群的等速肌耐力均没有影响;4%bw l后,屈肘肌群与屈、伸膝肌群的等速肌耐力不变,而伸肘肌群的等速肌耐力显著性下降。3)2%bw l和4%bw l对下肢的无氧耐力没有削弱作用。 相似文献
9.
《European Journal of Sport Science》2013,13(10):1336-1341
AbstractMatch-induced fatigue of knee muscle strength and agonist-antagonist strength-ratios may affect both performance and risk of injury in soccer players. Once explosive tasks are imperative in soccer as well as hamstring strain injuries occur during high-velocity moments, rapid force capacity of this muscle group is especially important. This study evaluated the effect of match-induced fatigue on knee muscle strength and strength-ratio parameters after a single professional soccer match. Male professional soccer players (n?=?16; 24.2?±?3.9 years) were tested before and after a soccer match (56.2?±?22.6?min of playing) for knee flexors (hamstring) and extensors (quadriceps) isometric peak torque (MVC) and rate of torque development (RTD) – as well as the hamstring-to-quadriceps ratio (H:Q) – at 30° of knee flexion. Knee injuries often occur at this joint angle, which is common in sprinting, pivoting, sidecutting, and jumping. Match-induced fatigue caused a left shift in the knee extensors torque-time curve with no significant change in both early (i.e. 0–50?ms) and late (i.e. 0–200?ms) RTD, and a right shift in the knee flexors torque-time curve with a decrease in early RTD (～16%, p?=?.029) and late RTD (～11%, p?=?.011). Knee extensors and knee flexors peak torque remained unchanged (p?>?.05). Early RTD H:Q decreased by～24% (p?=?.027), while late RTD H:Q and MVC H:Q remained unchanged (p?>?.05). In conclusion, match-induced fatigue impaired the ability to rapidly produce force at an angle where injuries are most susceptible to occur. Important information is missed if only the traditional H:Q is considered. 相似文献
10.
《European Journal of Sport Science》2013,13(4):277-282
Abstract In the present study, we examined the relationships between muscle volume and joint torque for the elbow flexors and extensors in young and elderly individuals, with the aim of evaluating age effects on these relationships. The participants were 45 young (27 men and 18 women aged 20–37 years) and 51 elderly (19 men and 32 women aged 60–77 years) individuals. The joint torques developed during isometric maximal voluntary elbow flexion and extension were measured using a torque meter. The muscle volumes of the elbow flexors and extensors were determined by magnetic resonance imaging. For the elbow flexors, joint torque was significantly correlated with muscle volume in both young and elderly individuals (r=0.564–0.872). There were also significant correlations between muscle volume and joint torque for the elbow extensors in elderly men and women as well as in young men and women (r=0.715–0.826). None of the y-intercepts of the regression lines between muscle volume and joint torque were significantly different from zero. Furthermore, no significant age or gender effects on the joint torque per muscle volume of the elbow flexors and extensors were observed. The present results suggest that muscle volume is a main determinant of joint torque regardless of age and gender, for both muscle groups. 相似文献
11.
李秋萍 《沈阳体育学院学报》2008,27(4):67-69
采用CYBEX6000等速测力仪,对30名优秀的速滑运动员髋关节屈伸肌群峰值力矩、平均功率、总功输出及屈/伸肌比值(%)进行了比较与分析。结果表明:双髋关节屈伸肌峰值力矩、总功输出均随角速度增加而下降,平均功率则升高;同一速度区髋关节屈伸肌的峰值力矩、平均功率、总功伸肌大于屈肌;不同速度区伴有"优势交换"现象,即低速区左侧屈伸肌大于右侧,高速区则以右侧伸肌增强为主。速滑运动员髋关节屈/伸肌比值(%)随角速度增加而下降。 相似文献
12.
自由式滑雪女子空中技巧优秀运动员下肢肌力与静态平衡能力特征 总被引：1，自引：1，他引：0
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
13.
通过对两名高水平女子链球运动员双侧的髋关节和膝关节进行等速测试,探究运动员髋关节和膝关节周围肌群的生物力学特性,为运动训练和运动康复等提供理论依据。利用等速肌力测试系统对两名运动员的髋关节和膝关节屈伸肌群以及髋关节的旋内旋外肌群进行等速测试。结果发现:两名运动员双侧髋关节和膝关节屈伸肌群以及髋关节的旋内旋外肌群的峰力矩随测试速度的增加呈递减趋势,髋膝关节峰力矩屈伸比和髋关节旋内旋外比随既定测试速度的增加呈递增趋势;同一测试速度下,伸肌肌群的峰力矩大于屈肌肌群,髋关节旋外肌群的峰力矩大于旋内肌群。 相似文献
14.
等速测力在散打运动训练监控中的应用 总被引：4，自引：0，他引：4
姜传银 《上海体育学院学报》2005,29(1):60-63
采用等速测力的方法，对优秀散打运动员进行跟踪测试。结果发现：提高散打运动员背部和膝部速度力量的周期，明显长于提高最大力量的周期；评价散打运动员训练水平的力量参考指标为背部伸肌最大力量，背部伸肌和屈肌速度力量，左膝部屈肌最大力量及收缩速度，左膝部伸肌速度力量，右膝伸肌最大力量，右膝伸肌速度力量。 相似文献
15.
Biomechanical differences in soccer kicking with the preferred and the non-preferred leg 总被引：2，自引：2，他引：0
The aims of this study were to examine the release speed of the ball in maximal instep kicking with the preferred and the non-preferred leg and to relate ball speed to biomechanical differences observed during the kicking action. Seven skilled soccer players performed maximal speed place kicks with the preferred and the non-preferred leg; their movements were filmed at 400 Hz. The inter-segmental kinematics and kinetics were derived. A coefficient of restitution between the foot and the ball was calculated and rate of force development in the hip flexors and the knee extensors was measured using a Kin-Com dynamometer. Higher ball speeds were achieved with the preferred leg as a result of the higher foot speed and coefficient of restitution at the time of impact compared with the non-preferred leg. These higher foot speeds were caused by a greater amount of work on the shank originating from the angular velocity of the thigh. No differences were found in muscle moments or rate of force development. We conclude that the difference in maximal ball speed between the preferred and the non-preferred leg is caused by a better inter-segmental motion pattern and a transfer of velocity from the foot to the ball when kicking with the preferred leg. 相似文献
16.
H.C. Dörge T. Bull Andersen H. SØrensen E.B. Simonsen 《Journal of sports sciences》2013,31(4):293-299
The aims of this study were to examine the release speed of the ball in maximal instep kicking with the preferred and the non-preferred leg and to relate ball speed to biomechanical differences observed during the kicking action. Seven skilled soccer players performed maximal speed place kicks with the preferred and the nonpreferred leg; their movements were filmed at 400 Hz. The inter-segmental kinematics and kinetics were derived. A coefficient of restitution between the foot and the ball was calculated and rate of force development in the hip flexors and the knee extensors was measured using a Kin-Com dynamometer. Higher ball speeds were achieved with the preferred leg as a result of the higher foot speed and coefficient of restitution at the time of impact compared with the non-preferred leg. These higher foot speeds were caused by a greater amount of work on the shank originating from the angular velocity of the thigh. No differences were found in muscle moments or rate of force development. We conclude that the difference in maximal ball speed between the preferred and the non-preferred leg is caused by a better inter-segmental motion pattern and a transfer of velocity from the foot to the ball when kicking with the preferred leg. 相似文献
17.
Blackwell J Knudson D 《Sports biomechanics / International Society of Biomechanics in Sports》2002,1(2):187-192
This study investigated the effect of the larger diameter (Type 3) tennis ball on performance and muscle activation in the serve. Sixteen male advanced tennis players performed serves using regular size and Type 3 tennis balls. Ball speed, surface electromyography, and serve accuracy were measured. There were no significant differences in mean initial serve speeds between balls, but accuracy was significantly greater (19.3%) with the Type 3 ball than with the regular ball. A consistent temporal sequence of muscle activation and significant differences in mean activation of different muscles were observed. However, ball type had no effect on mean arm muscle activation. These data, combined with a previous study, suggest that play with the larger ball is not likely to increase the risk of overuse injury, but serving accuracy may increase compared to play with the regular ball. 相似文献
18.
John Blackwell Duane Knudson 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(2):187-191
This study investigated the effect of the larger diameter (Type 3) tennis ball on performance and muscle activation in the serve. Sixteen male advanced tennis players performed serves using regular size and Type 3 tennis balls. Ball speed, surface electromyography, and serve accuracy were measured. There were no significant differences in mean initial serve speeds between balls, but accuracy was significantly greater (19.3%) with the Type 3 ball than with the regular ball. A consistent temporal sequence of muscle activation and significant differences in mean activation of different muscles were observed. However, ball type had no effect on mean arm muscle activation. These data, combined with a previous study, suggest that play with the larger ball is not likely to increase the risk of overuse injury, but serving accuracy may increase compared to play with the regular ball. 相似文献
19.
Blauer L. Bangerter 《Research quarterly for exercise and sport》2013,84(3):432-436
Abstract The degree of contribution to performance of the vertical jump by leg components plantar flexors, knee extensors, and hip extensors was determined experimentally and tested by analysis of covariance. One control and four experimental groups from 100 college men at Brigham Young University were randomly assigned to varying muscle strengthening programs for 8 weeks. Initial and final vertical jump tests and strength measures were administered. Gains in the vertical jump significant beyond the .05 level were registered by experimental groups which strengthened knee and/or hip extensors. Control and plantar flexor strengthening groups did not register significant jump gains. Each experimental group registered significant isotonic strength gains in the programed muscle groups. 相似文献
20.
青少年男子短跑运动员膝关节等速肌力特征研究 总被引：14，自引：0，他引：14
目的：通过对36名二级青少年男子短跑运动员双侧膝关节进行等速测试，探析青少年短跑运动员膝关节向心屈伸肌群的生物力学特性．为运动训练、科学选材及临床康复等提供理论依据。方法：利用Kinitech等速康复肌力测试系统对青少年男子短跑运动员膝关节屈伸肌群进行等速测试。结果：青少年男子短跑运动员双侧膝关节屈伸峰力矩随测试速度的增加呈递减趋势，且膝伸肌大于膝屈肌（P〈0．05），峰力矩屈伸比（V／E）随给定测试速度的增加呈递增趋势；最大功率随测试速度的增大而增加，同一测试速度下屈、伸肌群最大功率无明显差异，左、右侧相比也无显著性差异（600／s伸肌除外）；屈伸肌群达峰力矩的角度（APT）表现为伸肌角度明显低于屈肌角度，随速度增加左右两侧膝关节达峰力矩的角度无显著差异：双侧膝关节屈伸肌群达峰力矩的时间（TPT）随测试速度的增加而减小，同一测试速度下伸肌达峰力矩的时间大于屈肌；右侧膝关节屈肌相对峰力矩（PT／BM）与下肢形态学指标表现出不同程度的正相关。结论：青少年男子短跑运动员膝关节峰力矩变化规律与成年人相一致，但左右侧膝关节屈伸肌群做功能力发展不平衡，屈伸肌群运动达峰力矩角度、达峰力矩的时间存在显著差异。 相似文献