共查询到20条相似文献，搜索用时 359 毫秒
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Brent James Raiteri 《European Journal of Sport Science》2018,18(8):1128-1138
There is an abundance of evidence that suggests elastic tendons can enhance both animal and human muscle performance. However, in many terrestrial animals, including humans, a large proportion of the elastic tissue within the muscle-tendon unit is located within the muscle. This continuous elastic sheet, which provides muscle fibre attachment, is known as the aponeurosis. The aponeurosis has a much more complicated shape than the free tendon and it undergoes a more complicated loading regime during contraction, due to its relationship with the bulging muscle fibres, which remain isovolumetric during force production. Muscle contraction may dynamically modulate the stiffness of the aponeurosis at the same active versus passive force, by increasing the intramuscular pressure and transverse forces within the muscle, which may stretch the aponeurosis in width and subsequently reduce its longitudinal strain. Some evidence also suggests that the aponeurosis mechanical properties may be affected by muscle length, which appears to reduce the fascicle strains for a given muscle force at longer muscle lengths. This narrative review outlines the animal and human studies that have investigated aponeurosis behaviour during contraction and discusses how an elastic sheet with a variable stiffness under activation might be beneficial for muscle performance. While it is clear that our understanding of the role of aponeurosis is lacking, it is hoped that further work will attempt to determine how this tissue contributes to power amplification and elastic energy savings during locomotion and potentially uncover how aponeurosis behaviour contributes to injury risk. 相似文献
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《European Journal of Sport Science》2013,13(9):1195-1203
AbstractThe purpose of this study was to investigate the time course of the changes of muscle-tendon mechanical properties and the function responses of the plantar flexor muscles following 5?×?60?s of static stretching.Fourteen healthy volunteers were tested on four separate days in a random order with three different rest times (0, 5, 10?min) after 5?×?60?s of stretching or following a control period without stretching. During each test, the dorsiflexion range of motion (RoM), passive resistive torque (PRT), and maximum voluntary contraction (MVC) were measured with a dynamometer. Ultrasonography of the gastrocnemius medialis (GM) muscle-tendon junction displacement and motion capture allowed us to determine the length changes in the tendon and muscle, respectively, and hence to calculate their stiffness.We observed an increase in RoM and decrease in MVC at 0, 5, and 10?min post-stretching. This could be attributed to an increase in muscle elongation which lasted at least 10?min. A decrease in muscle-tendon stiffness was observed immediately, but not 5 or 10?min after the stretching. A decrease in PRT and muscle stiffness was observed up to 5?min after the stretching. No changes were detected in tendon stiffness or in any variable in the control group.The effects of a 5?×?60?s static stretching exercise changes the muscle-tendon functions (RoM, MVC), which are related to mechanical changes of the muscle but not the tendon structure, respectively. Although the functional changes last for at least 10?min, changes in muscle stiffness were only observed up to 5?min after the stretching exercise. 相似文献
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Romanov N Fletcher G 《Sports biomechanics / International Society of Biomechanics in Sports》2007,6(3):434-452
The relationship between the affect and timing of the four forces involved in running (gravity, ground reaction force, muscle force, and potential strain energy) is presented. These forces only increase horizontal acceleration of the centre of mass during stance but not flight. The current hierarchical models of running are critiqued because they do not show gravity, a constant force, in affect during stance. A new gravitational model of running is developed, which shows gravity as the motive force. Gravity is shown to cause a torque as the runner's centre of mass moves forward of the support foot. Ground reaction force is not a motive force but operates according to Newton's third law; therefore, the ground can only propel a runner forward in combination with muscle activity. However, leg and hip extensor muscles have consistently proven to be silent during leg extension (mid-terminal stance). Instead, high muscle-tendon forces at terminal stance suggest elastic recoil regains most of the centre of mass's height. Therefore, the only external motive force from mid-terminal stance is gravity via a gravitational torque, which causes a horizontal displacement. The aim of this paper is to establish a definitive biomechanical technique (Pose method) that is easily taught to runners (Romanov, 2002): falling forwards via a gravitational torque while pulling the support foot rapidly from the ground using the hamstring muscles. 相似文献
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It is widely assumed that there is an eccentric hamstring muscle fibre action during the swing phase of high-speed running. However, animal and modelling studies in humans show that the increasing distance between musculotendinous attachment points during forward swing is primarily due to passive lengthening associated with the take-up of muscle slack. Later in the swing phase, the contractile element (CE) maintains a near isometric action while the series elastic (tendinous) element first stretches as the knee extends, and then recoils causing the swing leg to forcefully retract prior to ground contact. Although modelling studies showed some active lengthening of the contractile (muscular) element during the mid-swing phase of high-speed running, we argue that the increasing distance between the attachment points should not be interpreted as an eccentric action of the CE due to the effects of muscle slack. Therefore, there may actually be no significant eccentric, but rather predominantly an isometric action of the hamstrings CE during the swing phase of high-speed running when the attachment points of the hamstrings are moving apart. Based on this, we propose that isometric rather than eccentric exercises are a more specific way of conditioning the hamstrings for high-speed running. 相似文献
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有氧能力的高低是马拉松跑者能否取得优异成绩的关键。最大摄氧量、乳酸阈和跑步经济性是衡量运动员有氧能力和耐力运动表现的关键指标，也是长跑训练效果的核心考量。由于力量和耐力训练对机体产生不同的训练刺激，教练员和运动员很少将力量训练作为提升耐力运动表现的手段，以防止有氧能力受到负面影响。通过对大量文献梳理发现，力量训练可以在不影响机体最大摄氧量和乳酸阈值的前提下，通过改善神经肌肉功能、转换肌纤维类型以及增强肌肉肌腱刚度和利用弹性势能的能力，提高跑步经济性和无氧能力，改善运动员耐力运动表现。本文基于对力量、耐力训练的生理学适应的探讨，总结不同形式力量训练对耐力运动表现的影响与作用机制，并为马拉松选手科学安排力量训练提出建议，从而优化其耐力运动表现。 相似文献
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Gregory C. Bogdanis Athanasios Tsoukos Spyridon K. Methenitis Elisavet Selima Panagiotis Veligekas Gerasimos Terzis 《European Journal of Sport Science》2019,19(3):345-353
This study compared knee angle-specific neuromuscular adaptations after two low-volume isometric leg press complex training programmes performed at different muscle lengths. Fifteen young males were divided into two groups and trained three times per week for 6 weeks. One group (n?=?8) performed 5–7 sets of 3 s maximum isometric leg press exercise, with 4?min recovery, with knee angle at 85°?±?2° (longer muscle-tendon unit length; L-MTU). The other group (n?=?7) performed the same isometric training at a knee angle of 145°?±?2° (180°?=?full extension; shorter muscle-tendon unit length; S-MTU). During the recovery after each set of isometric exercise, participants performed two CMJ every minute, as a form of complex training. Maximum isometric force (MIF) and rate of force development (RFD) were measured over a wide range of knee angles. Countermovement jump (CMJ) performance and maximum half-squat strength (1RM) were also assessed. Training at S-MTU induced a large increase of MIF (22–58%, p?p?p?=?0.001). In contrast, training at L-MTU, resulted in a moderate and similar (≈12.3%, p?=?0.028) improvement of force at all knee angles. CMJ performance and 1RM were equally increased in both groups after training by 10.4%?±?8.3% and 7.8%?±?4.7% (p?相似文献
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黄海 《西安体育学院学报》1993,(1)
骨骼肌的发展水平是受收缩蛋白合成与分解的影响,本文以小白鼠为对象研究表明运动刺激能使骨骼肌活性化高的收缩蛋白合成,同时在量上明显增加。肌动蛋白和肌球蛋白的相互收缩反应说明运动刺激可以使骨骼肌对Ca离子感受性生理机能得到明显改善,肌动球蛋白Mg-ATP_(ase°)的活性随Ca离子浓度增加而升高,表明骨骼肌收缩蛋白在质和量的变化,可能是肌动球蛋白Mg-ATP_(ase°)的活性增高而引起。 相似文献
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目的:测试静态拉伸训练前、后男性青年排球运动员踝关节跖-背屈动作和落地缓冲动作生物力学参数,分析静态拉伸对踝关节动力学及下肢缓冲特征影响的机制及意义。方法:22名健康男性青年高水平排球运动员随机分为实验组和对照组,对实验组进行36组下肢静态拉伸训练。分别于训练前、12组训练后、24组训练后、36组训练后、停训4周恢复期后测试踝关节跖-背屈动力学和缓冲期下肢及下肢各关节动力学、运动学数据,同步测试小腿后肌群影像学。结果:12组训练后至恢复期踝关节跖-背屈范围增加非常显著(P<0.01),小腿后肌群被动刚度显著降低(P<0.05),二者的增加/降低率%于36组训练后改变最明显(P<0.05),且变化率%之间呈非常显著正相关(P<0.01)。训练后小腿后肌群滞后%明显降低(P<0.05),肌腱弹性回缩率%明显升高(P<0.05),且二者之间呈显著负相关(P<0.05)。下肢刚度显著降低(P<0.05),髋、膝、踝关节做功均显著增加(P<0.05),训练各阶段踝关节做功贡献度均最大(P<0.05)。结论:静态拉伸训练早期即可通过降低肌肉-肌腱复合体被动刚度而增加关节活动范围和通过降低滞后而提高肌腱弹性回缩率并保持至恢复期,提示,静态拉伸训练急性期和慢性期均能提高肌肉-肌腱复合体的柔韧性及肌腱的弹性能利用率,从而有利于提高拉长-缩短周期运动表现。训练后各阶段下肢刚度降低的同时各关节缓冲吸能增加且踝关节是吸能的主要部位,提示,静态拉伸可通过调整缓冲模式、提高关节能量吸收、增效踝关节作用降低排球运动员下肢损伤的风险。 相似文献
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ABSTRACTThis study aimed to investigate the influence of foot strike patterns on the behaviour of the triceps surae muscle-tendon unit, including the Achilles tendon whose length nearly corresponds to force of the triceps surae, and the medial gastrocnemius muscle (MG) during running. Seven male volunteers ran with forefoot and rearfoot strikes at 10, 14 and 18 km h?1 on a treadmill. The MG fascicle length was measured using ultrasonography. The in vivo length of the curved Achilles tendon was quantified by combining ultrasonography with optical motion capture of reflective markers on the right lower limb and an ultrasound probe. The forefoot strike resulted in a significantly shorter MG fascicle length at the initial contact, at Achilles tendon peak elongation, and at toe-off, than the rearfoot strike. The Achilles tendon length at initial contact was greater during the forefoot strike than during the rearfoot strike at 18 km h?1, while its peak elongation was not significantly different during forefoot and rearfoot running. These results indicate that the MG, with a shorter length during forefoot running, manages to address demands for a similar peak force of the triceps surae than during rearfoot running. 相似文献
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运动对骨骼肌收缩蛋白的影响 总被引：2，自引：0，他引：2
本文观察运动和不运动组小白鼠骨骼肌收缩蛋白含量,Mg—ATPase 活性以及对 Ca~(2+)感受性的生理特性。我们发现:运动不仅可以使骨骼肌收缩蛋白含量增加,而且活性化高的蛋白同时合成,肌动蛋白和肌球蛋白的相互收缩反应说明运动可使骨骼肌对 Ca~(2+)的感受性明显改善,肌动球蛋白 Mg—ATPase 的活性增高。结果表明:骨骼肌收缩蛋白在质和量的变化,可能是由肌动球蛋白 Mg—ATPase 的活性增高而引起。 相似文献
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运用Vicon运动影像捕捉分析系统,对运动训练专业二级运动员原地纵跳、半蹲跳及不同高度下落跳深动作进行采集与三维重构,运用V3D系统完成身体质心位置坐标计算。依据肌肉收缩理论,借鉴前人对肌肉弹性能利用的计算方法,对受试者不同高度下落跳深的弹性能利用率进行测试分析。结果表明:一般水平的运动员跳深练习中肌肉弹性能利用率,随着下落高度的增加,表现出"增大—峰值—下降"的单峰波特征,最大利用率大约出现在40 cm的下落高度;原地纵跳练习的肌肉弹性能利用率与跳深练习的最大利用率相接近;仅就肌肉弹性能的利用方面,原地纵跳是一种较好的训练方法。 相似文献
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García-Manso JM Rodríguez-Ruiz D Rodríguez-Matoso D de Saa Y Sarmiento S Quiroga M 《Journal of sports sciences》2011,29(6):619-625
In this study, we used tensiomyography (TMG) to assess muscle status immediately after an ultra-endurance triathlon. Maximal radial displacement or deformation of the muscle belly, contraction time, delay time, sustain time, and relaxation time were measured for both legs, and dependent t-tests were used to compare means between the beginning and end of the race. The 19 men assessed (age 37.9 ± 7.1 years; height 177.5 ± 4.6 cm; weight: 73.6 ± 6.5 kg) participated in the 2009 edition of the Lanzarote Ironman. Deterioration in the neural response was observed for contraction time (P = 0.008) and relaxation time (P = 0.011), with a moderate decrease in the response time (sustain time) and a loss in muscle stiffness (deformation of the muscle belly). The effect of muscle fatigue on the rectus femoris and biceps femoris was different. Barely any changes in contraction time, relaxation time, sustain time, and deformation of the muscle belly were observed, while only the contraction response time decreased to a significant extent (reduction in delay time; P = 0.003). The considerable loss in contractile capacity induced by a long-distance race was reflected in changes in the neuromuscular response and fluctuations in the contractile capacity of the muscle. These modifications, derived from a prolonged, exhausting effort, can be assessed in a simple, non-aggressive, non-invasive way using tensiomyography. 相似文献
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《European Journal of Sport Science》2013,13(2):155-163
Abstract The purpose of this study was to quantify and compare Resultant Muscle Torque (RMT) and muscle activation (EMG) pattern, during resistance exercise comprising eight repetitions maximum (8 RM) biceps curl with elastic resistance and free weight exercise. Sixteen male and female recreationally active subjects completed 8 RM biceps curl by each of three modalities of resistance exercise: (i) dumbbell (DB), (ii) elastic tubing with original un-stretched length at the commencement of contraction (E0), and (iii) elastic tubing with 30% decrement of original length (E30) at the commencement of contraction. The magnitude of muscle activation, external force, acceleration as well as range of motion (ROM) were quantified and synchronised by specific software. The data were collected from all eight repetitions but the first (initial), the fifth (middle) and the eighth (last) repetitions were selected for further data analysis. Each selected repetition was partitioned into a concentric and eccentric phase and then each phase was further divided into three equal segments (3 concentric and 3 eccentric = 6 segments per repetition). The EMG and RMT data demonstrated a bell-shaped muscle activation and muscle torque production pattern for the three modes of exercise. The E30 resulted in 15.40% and 14.89% higher total EMG (µV) as well as 36.85% and 17.71% higher RMT (N · m) than E0 and DB, respectively (all P <0.05). These findings support the contention that an elastic resistance device (E30) has the capacity to provide an appropriate high resistance stimulus to meet the training requirement of elite athletes. 相似文献
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Popadic Gacesa J Dragnic NR Prvulovic NM Barak OF Grujic N 《Journal of sports sciences》2011,29(6):635-641
The aim of this study was to determine whether triceps brachii muscle volume can be adequately estimated from a single anatomical cross-sectional area (ACSA) and can the same model be used for prediction after training. Thirty-five healthy male non-athletes (age 21.6 ± 2.5 years, body mass index 24.8 ± 3.5 kg · m(-2)) volunteered for this study. The volumes of the upper arm extensors were calculated from magnetic resonance imaging (MRI) sequence scans and regression models were developed, which were used to predict muscle volumes from single MRI cross-sectional scans taken at different points along the humerus length. The same procedure was repeated after 12 weeks of maximal resistance training of the elbow extensors. Correlation coefficients were calculated for Model A with CSA(max), humerus length (HL), and body mass index (r = 0.919), a model with CSA(50%) and HL (r = 0.922), and a model with CSA(60%) and HL (r = 0.920) (P < 0.001). The standard error of estimate for Model A, Model CSA(50%), and Model CSA(60%) was 8.0%, 7.7%, and 7.8% respectively. Thesame prediction formula can be used for the left arm (r = 0.904). If a single ACSA is used for triceps brachii volume prediction, the best fit is with Model CSA(60%) and HL, both before and after training (r = 0.941). By introducing humerus length into the calculation, we simplify the procedure for volume measurement, since it can be obtained during MRI scanning. 相似文献
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优秀女子足球运动员专项心理素质结构研究 总被引：2，自引：0，他引：2
侯卫东 《天津体育学院学报》2004,19(1):65-69
通过对6名优秀青少年速滑运动员进行SJ、CMJ和3个不同高度的DJ测试,分析比较优秀青少年速滑运动员下肢骨骼肌弹性势能利用率的差异,以反映其下肢骨骼肌的力学特性,为研究速滑运动下肢骨骼肌的力学特性及运动选材做出铺垫。结果表明:弹性势能利用率存在性别差异,男性受试者弹性势能利用率高于女性,并与运动员等级、体重保持一定正相关;随负荷的增加,运动员下肢肌肉弹性势能的利用率却逐渐下降;外加负荷条件下,弹性势能利用率较其他项目低,建议加强肌肉速度力量与超等长力量的训练,以提高肌肉稳定性。 相似文献
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优秀青少年速滑运动员下肢骨骼肌弹性势能利用率特征研究 总被引：2，自引：0，他引：2
在以影响因子为核心的期刊评估系统基础上,根据关系型动态思维模式,运用多维定位的原则,利用德尔菲意见法、文献法、逻辑推理法,引入引文支持概念,从引文的多学科特征和应用类型两个特征上,利用文献分类法、图表法、多元统计、聚类分析、数值分类等多种方法,对中文体育核心期刊在引文支持元数据中的特征分布值分别进行统计,目的是从多视角对期刊质量重新进行评价,提高社会对使用影响因子评价核心期刊的认可程度。结论:13种核心期刊在多学科上的分布程度为34.84%,超过多学科丰度值的期刊有5种,形成创新性学术期刊集;13种核心期刊在应用类型上的分布程度为5.10%,超过应用类型丰度值的期刊有6种,形成应用性学术期刊集。两集合中的数据经处理后可以参加以影响因子为核心的中文体育核心期刊排序结果的微调。 相似文献
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Our purpose was to compare the effect of a periodized preparation consisting of power endurance training and high-intensity power training on the contractile properties of the quadriceps muscle and functional performances in well trained male sprinters (n = 7). After 4 weeks of high-intensity power training, 60-m sprint running time improved by an average of 1.83% (SD = 0.96; p < .05). This improvement was inversely related to an increase in maximal voluntary contraction torque (r = -.89, p < .05) and poorly correlated with changes in the contractile kinetics of the quadriceps muscle (r range from .36 to -.46). These findings suggest that sprint performance is poorly predicted by muscle intrinsic properties and that a neural adaptation appears to explain most of the observed functional adaptations. 相似文献
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Recumbent bicycles (RB) are high performance, human-powered vehicles. In comparison to normal/upright bicycles (NB) the RB may allow individuals to reach higher speeds due to aerodynamic advantages. The purpose of this investigation was to compare the non-aerodynamic factors that may potentially influence the performance of the two bicycles. 3D body centre of mass (BCoM) trajectory, its symmetries, and the components of the total mechanical work necessary to sustain cycling were assessed through 3D kinematics and computer simulations. Data collected at 50, 70, 90 110 rpm during stationary cycling were used to drive musculoskeletal modelling simulation and estimate muscle-tendon length. Results demonstrated that BCoM trajectory, confined in a 15-mm side cube, changed its orientation, maintaining a similar pattern across all cadences in both bicycles. RB displayed a reduced additional mechanical external power (16.1 ± 9.7 W on RB vs. 20.3 ± 8.8 W on NB), a greater symmetry on the progression axis, and no differences in the internal mechanical power compared to NB. Simulated muscle activity revealed small significant differences for only selected muscles. On the RB, quadriceps and gluteus demonstrated greater shortening, while biceps femoris, iliacus, and psoas exhibited greater stretch; however, aerodynamics still remains the principal benefit. 相似文献