力量素质对正脚背踢球动作腘绳肌生物力学特征的影响

目的：分析正脚背踢球动作中下肢和腘绳肌生物力学特征参数,探讨踢球动作腘绳肌拉伤危险时相,同时探究腘绳肌和股四头肌力量素质与踢球动作下肢和腘绳肌生物力学特征的关系,进一步明确踢球动作中腘绳肌拉伤机制。方法：以15名足球专项国家一级运动员为受试者,采集180(°)/s动作角速度下的等速腘绳肌向心(H_con)、腘绳肌离心(H_ecc)、股四头肌向心峰值力矩(Q_con);采集受试者最大力正脚背踢球动作运动学和肌电数据,根据腘绳肌肌肉起止点和髋、膝关节中心的相对位置获得肌肉起止点坐标,从而获得腘绳肌3块双关节肌肌肉-肌腱复合体(muscle-tendon unit,MTU)长度,以MTU拉伸速度和标准化MTU长度为分析指标。采用样条插值法对各指标按踢球动作周期阶段进行3次归一化处理。结果：腘绳肌3块双关节肌在正脚背踢球动作小腿前摆阶段和触球随摆阶段处于激活状态并被拉长,进行离心收缩;触球随摆阶段3块双关节MTU拉伸速度、肌标准化MTU长度、肌肉激活程度均显著大于小腿前摆阶段(P<0.05),标准化MTU长度在触球随摆阶段中期达...     

肌肉急性拉伤后的生物力学研究现状

肌肉拉伤模型的建立为人们从生物力学和组织学深入研究提供了可能性。虽然国内的一些学者已建立了肌肉慢性拉伤(劳损)的动物模型,如吕丹云(1982)、于长隆和曲绵域等(1985),但他们只是进行了病理学和组织学研究而未进行生物力学研究。夏剑英(1987)建立了大鼠腓肠肌急性拉伤模型,用电刺激仪刺激腓肠肌两端,引起腓肠肌强直收缩,踝关节跖屈,与此同时,一重物从固定高度自由下落,以一个基本恒定的初始冲量,迫使踝关节迅速背屈被拉伤。Nikolaou(1987)用新西兰白兔的胫骨前肌建立了肌肉急性拉伤模型,采用10cm/     

优秀田径运动员腘绳肌拉伤后的肌力特征分析

运用CYBEX-Norm型等速肌力测试与康复系统,以上海市优秀田径运动员为研究对象,探讨腘绳肌拉伤后的等速参数变化,分析伤后的恢复情况.结果显示：受伤运动员伤侧腘绳肌峰力矩角度明显增大,表明拉伤腘绳肌达到最大力量的时间明显延长,最大收缩长度发生了改变.建议：在运动实践中,合理运用等速测试的峰力矩角指标作为腘绳肌拉伤后恢复效果的监控指标,并结合适当比例的离心训练,将有助于减少运动中腘绳肌的拉伤.     

浅析短跑运动放松训练

1、放松能力影响短跑成绩的生理因素1.1肌肉放松能增大肌肉收缩力量从运动生理学分析,跑的动力来源是肌肉工作时所产生的合力,而肌肉工作的效果主要取决于下列因素:肌肉中肌纤维的数量、肌肉收缩的初长度、单个肌纤维的收缩力、肌肉中的血液供应情况、肌肉对骨骼发生作用时的力学条件、协同肌对抗肌配合工作的协调性、中枢神经系统的机能状态。收缩时表现的力量越大,     

骨骼肌损伤后修复的组织学研究现状

对于同不方式引起骨骼肌损伤后的恢复已进行了大量的研究 ,其结果为无论是由挤压伤、过渡负荷、拉伤、挫伤等引起骨骼肌的急性损伤 ,其炎症细胞反应过程差异很小 ,修复愈合过程基本是一样的[1- 17] 。1　骨骼肌的正常结构骨骼肌 (ｓｋｅｌｅｔａｌｍｕｓｃｌｅ)是个运动器官 ,由肌腹 (ｂｅｌｌｙ)和肌腱 (ｔｅｎｄｏｎ)两部分组成。肌腹是肌肉的中间部分 ,主要由骨骼肌纤维 (ｓｋｅｌｅｔａｌｍｕｓ ｃｌｅｆｉｂｅｒ)构成 ,每条肌纤维表面包绕着的薄层结缔组织 ,称肌内膜 (ｅｎｄｏｍｙｓｉｕｍ ) ,肌内膜与肌纤维之间有基膜。数条或十数条…     

浅谈田径运动中肌肉拉伤与防治

一、肌肉拉伤的原因在全速疾跑时,大腿后群肌肉和小腿的肌肉产生剧烈的疼痛,无法继续跑进,即所谓的肌肉拉伤。在所有的运动项目中,发生肌肉拉伤最多的是短跑。容易产生肌肉拉伤的季节则是春秋之初和季节变化的时节。容易拉伤的肌肉:短跑是大腿后群肌肉;中常跑则是小腿后群肌肉。肌肉拉伤的感觉,宛如肌肉断了一样,实际上则是极少的一部分或局部拉伤。大腿后群肌肉拉伤,是田径运动中发生最多的运动损伤。拉伤的原因主要是由于肌肉做猛烈的收缩时,收缩力超过了肌肉本身所能承受的能力,而使肌肉发生损伤。运动医学认为:肌肉主动收缩时发生的肌肉拉伤叫“主动拉伤”,主动拉伤主要是肌纤维缩短时发生的,受伤时原动肌或协同肌都可能发生损伤。     

影响力量的主要因素

1 肌肉的生理横断面 :肌肉的生理横断面增大 ,则收缩力量相应增强。肌肉的生理横断面增大是由于肌纤维增粗、肌凝蛋白含量增加、肌毛细血管网增多、结缔组织增厚、肌糖元增加等因素造成的。2 神经系统的支配调节 :中枢神经系统发放神经冲动的强度大、频率高 ,则肌肉产生的力量也大 ;动员更多的运动单位参加工作 ,参与收缩肌纤维数量增多 ,则力量就增大 ;改善主动肌和协同肌、对抗肌之间的相互协调关系 ,对抗肌的放松能力是影响力量的重要因素。3 肌纤维类型 :肌纤维一般分为快肌纤维、慢肌纤维和中间型纤维三种类型。肌肉中不同类型肌纤维…     

一种非专用器械的离心力量练习——强制性拉伸肌肉

“强制性拉伸肌肉”实际上属于一种离心力量练习。即:肌肉在练习中虽积极地收缩,却仍被强制性拉伸作用力拉长了的工作形式。与肌肉的其它几种收缩形式相比,它的最大特点是能使肌肉产生较大的张力。早在1929年就有研究者(贝德)用青蛙实验证实了强制性拉伸肌肉后的肌力超过最大静力性肌力的1.5—2倍。还有研究者认为,离心收缩所产生的张力比最大向心收缩力大40％左右。可见,离心收缩是进行力量练习的最佳刺激。但在运动实践     

运动生理学辅导讲座 第六讲 身体素质及体育教学、训练的生理学基础

<正> 一、身体素质的生理学基础人体在肌肉活动中所表现出的力量、速度、耐力、灵敏及柔韧等机能能力统称为身体素质。 (一)力量素质力量是在肌肉紧张或收缩时所表现出来的一种能力。肌肉力量的大小取决于以下两方面:(1)肌肉横断面的大小。肌肉横断面愈大,肌肉收缩时所产生的力量也愈大。体育锻炼可使肌肉横断面增大,这是由于肌纤维增粗造成的。肌纤维增粗是由于肌凝蛋白质含量增加、肌毛细血管网增多、肌结缔组织增厚、肌糖元和酶的含量增加所致。(2)神经系统的调     

谈提高短跑协调放松能力

协调放松能力是指运动员在高速奔跑中,神经系统和运动系统协调配合,使肌肉收缩与放松能按照短跑技术动作的工作性质协调进行,从而增加跑的步频与步长。它能增加肌肉收缩前的肌纤维长度,特别是放松对抗肌群,有助于提高肌肉收缩速度,增加肌涨力,增大步长。     

Injury rate,mechanism, and risk factors of hamstring strain injuries in sports: A review of the literature

Hamstring strains are one of most common sports injuries. The purpose of this literature review is to summarize studies on hamstring strain injury rate, mechanism, and risk factors in the last several decades with a focus on the prevention and rehabilitation of this injury. Hamstring injury commonly occurs in sporting events in which high speed sprinting and kicking are frequently performed, such as Australian football, English rugby, American football, and soccer. Basic science studies have demonstrated that a muscle strain injury occurs due to excessive strain in eccentric contraction instead of force, and that elongation speed and duration of activation before eccentric contraction affect the severity of the injury. Hamstring strain injury is likely to occur during the late swing phase and late stance phase of sprint running. Shortened optimum muscle length, lack of muscle flexibility, strength imbalance, insufficient warm-up, fatigue, lower back injury, poor lumbar posture, and increased muscle neural tension have been identified as modifiable risk factors while muscle compositions, age, race, and previous injuries are non-modifiable risk factors. The theoretical basis of some of these risk factors, however, is lacking, and the results of clinical studies on these risk factors are inconsistent. Future studies are needed to establish the cause-and-effect relationships between those proposed risk factors and the injury.     

The effects of static stretching on speed and agility: One or multiple repetition protocols?

Although static stretching (SS) is utilized during warm-up before training and competition, the results about its effects on performance remain controversial. We examined whether performing a stretch of short-to-moderate duration (<60 sec) in a single repetition produces a similar or different effect on speed and agility performance from the effect which is produced while performing the same stretch in multiple repetitions of the same total duration. According to a repeated measurement design, 40 trained males were randomly assigned to either (1) a single repetition group or (2) a multiple repetition group. The participants in each group performed five trials: a control trial (no stretches were performed) and four experimental trials of SS protocols consisting of five exercises performed at either 20 sec (2 × 10 in the second group), 30 sec (3 × 10 in the second group), 40 sec (4 × 10 in the second group) or 60 sec (6 × 10 in the second group) of total duration. A two-way repeated measures analysis of variance showed that the participants in both group improved their speed performance in response to the 20-sec trial, whereas agility remained unaffected. Data analysis also revealed that the repetition number did not affect speed and agility performance. These data suggest that SS of short duration (<30 sec) may actually improve acute speed performance, whereas SS of moderate duration may not hamper speed and agility performance. Moreover, the effects of SS protocols are related to the total duration of each exercise and not to the number of repetitions in which each exercise is performed.     

Strength training

Literature concerning the theoretical role of spinal reflex circuits and their sensorimotor signals in proprioceptive neuromuscular facilitation (PNF) muscle stretching techniques was examined. Reviewed data do not support the assertion commonly made in PNF literature that contraction of a stretched muscle prior to further stretch, or contraction of opposing muscles during muscle stretch, produces relaxation of the stretched muscle. Further, following contraction of a stretched muscle, inhibition of the stretch reflex response lasts only 1 s. Studies examined suggested that decreases in the response amplitude of the Hoffmann and muscle stretch reflexes following a contraction of a stretched muscle are not due to the activation of Golgi tendon organs, as commonly purported, but instead may be due to presynaptic inhibition of the muscle spindle sensory signal. The current view on the complex manner by which the spinal cord processes proprioceptive signals was discussed. The ability of acute PNF stretching procedures to often produce a joint range of motion greater than that observed with static stretching must be explained by mechanisms other than the spinal processing of proprioceptive information. Studies reviewed indicate that changes in the ability to tolerate stretch and/or the vis‐coelastic properties of the stretched muscle, induced by PNF procedures, are possible mechanisms.     

The effects of stretching on knee flexor fatigue and perceived exertion

Abstract

The objective of this study was to examine the effects of acute static muscle stretch on hamstring muscle fatigue and perceived exertion between young adult men and women. Twenty volunteers participated in two experimental sessions, in which we assessed maximal-effort isokinetic knee flexor force (90° · s^?1) and the number of sub-maximal (50% maximal) knee flexor repetitions to the point of failure. Immediately before the sub-maximal contractions on one randomly selected session, participants received ten 30-s passive knee flexor muscle stretches. Perceived exertion was sampled with a modified Borg category-ratio scale following each sub-maximal repetition. Each participant's perceived exertion response was estimated every 10% across the sub-maximal repetitions, via linear interpolation and power-function modelling. The men generated significantly greater force than the women during both experimental sessions, while muscle stretching had no significant effect on the number of sub-maximal repetitions. When estimated via power-function modelling, perceived exertion increased at a significantly greater rate following muscle stretch. Perceived exertion was significantly greater for the women following muscle stretch than the men. The findings suggest that the elevation in perceived exertion following knee flexor muscle stretching may be greater in women than men, despite no significant alterations in mechanical measures of muscle fatigue.     

Re-examination of the possible role of Golgi tendon organ and muscle spindle reflexes in proprioceptive neuromuscular facilitation muscle stretching

Literature concerning the theoretical role of spinal reflex circuits and their sensorimotor signals in proprioceptive neuromuscular facilitation (PNF) muscle stretching techniques was examined. Reviewed data do not support the assertion commonly made in PNF literature that contraction of a stretched muscle prior to further stretch, or contraction of opposing muscles during muscle stretch, produces relaxation of the stretched muscle. Further, following contraction of a stretched muscle, inhibition of the stretch reflex response lasts only 1 s. Studies examined suggested that decreases in the response amplitude of the Hoffmann and muscle stretch reflexes following a contraction of a stretched muscle are not due to the activation of Golgi tendon organs, as commonly purported, but instead may be due to presynaptic inhibition of the muscle spindle sensory signal. The current view on the complex manner by which the spinal cord processes proprioceptive signals was discussed. The ability of acute PNF stretching procedures to often produce a joint range of motion greater than that observed with static stretching must be explained by mechanisms other than the spinal processing of proprioceptive information. Studies reviewed indicate that changes in the ability to tolerate stretch and/or the viscoelastic properties of the stretched muscle, induced by PNF procedures, are possible mechanisms.     

A Single 30-s Stretch Is Sufficient to Inhibit Maximal Voluntary Strength

While it has been well established that an acute stretching program can inhibit maximal muscle performance, the amount of stretching needed to produce the deleterious response is unknown. Therefore this study examined the dose-response relationship between acute stretching and strength inhibition. Eighteen college students performed a one repetition maximum (1-RM) test of knee-flexion following 0, 1, 2, 3, 4, 5, or 6 30-s bouts of hamstring stretching held at the limit of toleration. All seven dose variations were done by each subject, with each variation done on a separate day. One week separated each test, and the order of the stretch variations was balanced across the seven testing days. Stretching significantly (p < .05) reduced 1-RM after one 30-s stretch (5.4%), and continued to decrease 1-RM up to and including six 30-s stretches (12.4%). A single 30-s stretch, if held at the limit of toleration, is sufficient to cause an inhibition in a person's 1-RM. Additional bouts of stretching will further decrease the 1-RM, suggesting that multiple mechanisms may be involved in stretch-induced strength inhibition.     

山东省现役400米运动员运动损伤现状的调查与促进策略

采用文献资料法、问卷调查法、数理统计法以山东省现役400米运动员为调查对象,以山东省现役400米运动员的运动损伤为研究对象,对运动员的运动损伤情况进行了调查和分析。结果表明:山东省现役400米运动员运动损伤率高,受伤部位集中在大腿和腰部,损伤的类型形式大多为急性损伤的肌肉拉伤和慢性损伤的肌肉劳损。促进策略为加强思想教育,提高相关知识储备,合理安排训练,加强监控和及时采取积极措施,预防和避免运动员运动损伤的发生。     

Hip adductor muscle function in forward skating

Adductor strain injuries are prevalent in ice hockey. It has long been speculated that adductor muscular strains may be caused by repeated eccentric contractions which decelerate the leg during a stride. The purpose of this study was to investigate the relationship of skating speed with muscle activity and lower limb kinematics, with a particular focus on the role of the hip adductors. Seven collegiate ice hockey players consented to participate. Surface electromyography (EMG) and kinematics of the lower extremities were measured at three skating velocities 3.33 m/s (slow), 5.00 m/s (medium) and 6.66 m/s (fast). The adductor magnus muscle exhibited disproportionately larger increases in peak muscle activation and significantly prolonged activation with increased speed. Stride rate and stride length also increased significantly with skating velocity, in contrast, hip, knee and ankle total ranges of motion did not. To accommodate for the increased stride rate with higher skating speeds, the rate of hip abduction increased significantly in concert with activations of adductor magnus indicating a substantial eccentric contraction. In conclusion, these findings highlight the functional importance of the adductor muscle group and hip abduction–adduction in skating performance as well as indirectly support the notion that groin strain injury potential increases with skating speed.     

对我院本科学生田径六项考试中运动损伤的调查报告

本文对体育系本科２６５名学生在田径六项考试期间受伤情况进行了调查．结果损伤人数６０人，且多为急性损伤。标枪、跨栏、跳远等项目受伤率较高．鉴于以上情况，笔者提出预防措施与建议，以免影响学生成绩和身体损伤。     

Acute effects of passive muscle stretching on sprint performance

The results of previous research have shown that passive muscle stretching can diminish the peak force output of subsequent maximal isometric, concentric and stretch-shortening contractions. The aim of this study was to establish whether the deleterious effects of passive stretching seen in laboratory settings would be manifest in a performance setting. Sixteen members (11 males, 5 females) of a Division I NCAA track athletics team performed electronically timed 20 m sprints with and without prior stretching of the legs. The experiment was done as part of each athlete's Monday work-out programme. Four different stretch protocols were used, with each protocol completed on a different day. Hence, the test period lasted 4 weeks. The four stretching protocols were no-stretch of either leg (NS), both legs stretched (BS), forward leg in the starting position stretched (FS) and rear leg in the starting position stretched (RS). Three stretching exercises (hamstring stretch, quadriceps stretch, calf stretch) were used for the BS, FS and RS protocols. Each stretching exercise was performed four times, and each time the stretch was maintained for 30 s. The BS, FS and RS protocols induced a significant (P < 0.05) increase (approximately 0.04 s) in the 20 m time. Thus, it appears that pre-event stretching might negatively impact the performance of high-power short-term exercise.