短跑运动员途中跑支撑期摆动腿作用的运动学相关分析

为研究短跑运动员途中跑支撑阶段摆动腿对跑速的影响 ,采用高速摄影及影片解析、数理统计等方法 ,对我国短跑运动员途中跑支撑期摆动腿运动学特征等指标与身体重心速度、专项成绩之间的关系进行分析。结果表明 :途中跑中摆动腿最大摆动速度和平均摆动速度与支撑腿支撑时间显著相关 ,摆动腿的平均摆动速度与后蹬时间之间明显相关 ;摆动腿的摆动角速度与身体重心水平速度及垂直速度密切相关 ;支撑腿和摆动腿的角速度变化量与离地瞬间身体重心水平速度密切相关。提示 :加快摆动腿的摆动速度能有效提高缓冲和蹬伸速度 ,缩短支撑时间 ,提高途中跑的步频 ;摆动腿的摆动速度对加快身体重心水平速度有显著影响 ;加强和提高途中跑摆动腿的运动效果 ,提高短跑运动员下肢摆动工作肌群的力量。     

关于短跑途中跑前蹬阶段的机制探讨

短跑途中跑支撑时期的前蹬阶段,缩短前蹬时间是减小制动一的主要因素,鞭打式着地技术和高重心跑是缩短前蹬时间重要的技术环节。前蹬是后蹬必备的准备阶段。     

短跑途中跑臀部后坐对跑速的不利影响

臀部后坐是短跑运动员在途中跑时较为常见的一种不合理的跑动技术,其技术动作的不合理性表现在下肢的支撑与摆动动作上。由于臀部后坐,支撑腿从着地缓冲转变为后蹬,髋部伸展的速度与幅度降低,削弱髋关节的用力程度,使后蹬力量得不到充分地发挥。随着髋部伸展速度的降低,髋屈肌群被拉长的速度缓慢。当支撑腿后蹬结束再转换为前摆时,快速收缩的力量减退,不能有力地带动大腿快速前摆,导致摆动腿前摆动作迟缓。在跑动中容易造成蹬地腿与摆动腿配合不协调,达不到以摆促蹬、蹬摆结合的效果。那么,蹬伸与摆动所产生的力量不能有效地促进身体重心向水平方向快速移动,从而延长了支撑时间,对跑速的增长产生一些不利的影响。主要影响有以下几个方面。     

对我国优秀男子背越式跳高运动员起跳技术的三维运动学分析

采用爱捷运动录像快速反馈系统EIMG90,对背越式跳高起跳技术进行细致的分析,结果表明在摆动腿蹬离地面至起跳腿着地支撑阶段，我国运动员两腿着地点近，身体重心向下垂直速度小，这有利于保持起跳前的速度，起跳脚着地瞬间至最大缓冲阶段，摆动腿摆动角速度与起跳腿蹬离地面瞬间的重心向上垂直速度相关，与世界优秀运动员比，我国运动员在着地支撑瞬间身体内倾不够。     

短跑技术教学图解

<正>途中跑1.短跑途中跑技术与图解1.1完整技术阶段1.1.1每一单步可分为支撑阶段(可分为前支撑和蹬伸阶段)和腾空阶段(可分为前摆下压和折叠阶段)(见图1)1.1.2在支撑阶段中的前支撑阶段,身体处于减速状态,然后在蹬伸阶段再进行加速     

坐着跑产生的原因与纠正方法

原因一：跑时全脚掌着地跑是单脚前脚掌着地支撑与腾空相互交替的周期性运动。教学时，许多教师往往忽视提醒学生跑时前脚掌着地支撑腾空的动作要点，大多数学生下意识地认为跑是走的一种加速运动。练习时采用全脚掌着地支撑，后蹬用力不够，身体重心前移不到位，脚后跟着地次数频繁，从而造成坐着跑。纠正方法：1.让学生理解、掌握跑的动作要领。2.让学生体会前脚掌前扒、后蹬用力、重心前移及手脚摆动等一系列动作的协调连贯性练习。3.原地做前脚掌蹬跳起向前的动作分解练习。原因二：（上）下肢摆动幅度小跑时，（上）下肢是一种协调而连…     

对百米途中跑后蹬效果的研究

一、前言途中跑是百米全程中距离最长、速度最快的一个段落,其技术的优劣,直接影响百米跑的比赛成绩。因为百米跑运动员的成绩主要体现在其水平位移速度的快慢上,而不是在其垂直位移速度上。运动员通过提高水平速度来提高百米成绩。所以,短跑项目的教学和训练都以途中跑为重点。不论起跑、起跑后加速跑,还是途中跑,后蹬阶段都使人体获得向前的动力。腾空阶段人体重心抛物线轨迹也是由后蹬技术所决定的。在整个支撑阶段,后蹬时间和工作距离都比缓冲时间和距离长。     

不同水平男子百米运动员起跑和前三步加速三维技术分析

目的：分析一级和二级男子百米运动员起跑加速前三步支撑阶段下肢髋膝踝关节运动时序特征及角速度峰值、角度等运动学指标差异,探究影响起跑加速跑效果的关键技术因素。方法：采用三维高速红外摄像解析法(14个红外摄像头,250 Hz)对6名一级运动员和7名二级运动员的起跑前三步加速技术动作进行分析。结论：1)后蹬起跑器阶段,后腿摆动屈膝角速度峰值与后腿蹬伸过程膝关节角度是影响后蹬起跑器技术的关键运动技术指标,适当增大后腿蹬伸过程后腿膝角和后腿摆动过程中屈膝摆动角速度有利于提高后蹬起跑器效果;2)第一步支撑阶段,髋和膝的伸展作用主要体现在着地瞬间,支撑腿较小的髋角和较小的伸髋幅度,支撑腿较大的着地膝角和较小的伸膝幅度,以及更为前倾的躯干,更有利于缩短蹬伸加速时间和获得更好的水平蹬伸效果;3)第二步支撑阶段,着地瞬间摆动腿屈膝作用更为积极,支撑腿髋关节和膝关节同步伸展加速技术,较小的支撑腿髋关节、膝关节和踝关节角度和更为前倾的躯干是影响起跑加速效果的重要因素。     

我国优秀女子20 km竞走运动员后半程竞走技术的运动学研究

运用三维运动学分析方法,对参加国际田联竞走挑战赛女子20km比赛前8名运动员后半程中一个复步进行解析。结果表明,我国运动员在后半程中,运用的是步长较短,步频较快的技术风格;腾空时间总体上处于犯规时限的下限,膝关节从着地瞬间直至垂直支撑面保持了可见的伸直状态,但在最后冲刺阶段,膝角出现了模糊伸直过程;身体重心垂直位移、头顶位置上下起伏均高于世界优秀运动员平均水平,这既与踝关节后蹬伸展离地时机偏早、用力动作不充分有关,也与着地瞬间摆动腿前摆后的前伸着地动作不够积极有关。在注意后蹬动作的同时,还应强化摆动腿积极的前摆着地动作。躯干倾角基本处于正常范围之内,但左、右腿蹬伸用力不均衡造成身体重心左、右偏差较大的情况容易导致动作外观不稳定而被判罚技术犯规。我国运动员肩髋扭转角度较小是导致步长相对较短的一个重要成因。     

短跑着地缓冲的“阻力”因子分析

短跑途中跑技术由前摆、着地缓冲、后蹬、后摆四个阶段组成,它们是一个完整的统一体,相互联系、相互影响、相互促进,是人体在瞬间紧密配合的结果。从摆动腿前摆着地瞬间开始,至身体重心移至支撑腿垂直上方时止的这一阶段称为着地缓冲阶段。前摆着地缓冲也是跑进中受"阻力"最大的阶段,做好着地缓冲技术的主要作用就是要尽可能地减少着地时的阻力,为顺利进入到后蹬这一     

男子跳远运动员不同起跳级次及其起跳技术的运动学分析

采用现场定点高速摄像、录像分析以及数理统计等方法,通过对A、B两组起跳阶段不同时相身体重心水平速度和垂直速度的变化与着板角、起跳缓冲和蹬伸阶段膝角变化的比较分析。结果表明:成绩较好,缓冲阶段身体重心水平速度的减小值会略大,垂直速度的增加值则更大;而且,离板瞬间身体重心水平速度和垂直速度都呈现出相对较大的趋势。     

影响短跑途中跑前支撑阶段水平速度的主要因素

短跑途中跑前支撑阶段(缓冲阶段)的技术是田径运动和运动生物力学研究的重点之一。本文依据运动生物力学研究理论,寻找出影响前支撑阶段人体总重心水平速度的因素:(一)摆动腿大腿角速度;(二)着地角;(三)着地瞬间看地脚的向前水平速度;(四)前摆上臂角速度。     

短跑途中跑支撑阶段支撑腿关节肌肉生物力学特性的研究

采用测力、测角加速度和多机多分辨拍摄技术对短跑途中跑支撑阶段肌肉动力学特征进行关节内力矩的计算与分析。研究表明，运动员踝关节跖屈肌的最大力矩与跑的速度呈显著相关；膝关节的伸肌在接近一半的支撑时间内是做离心收缩，离心收缩肌力矩的峰值要高于向心收缩的肌力矩峰值，离地前20％时刻膝关节屈肌起重要作用；髋关节在支撑阶段存在关节屈伸肌群交替工作，在着地后瞬间有较大的屈肌力矩，在离地前髋关节伸肌起重要作用，支撑阶段下肢关节肌肉快速退让性的离心收缩与主动收缩起同样重要的作用。     

前手翻接直体前空翻和直体前空翻转体360度动作的连接技术特征

前手翻是连接空翻与空翻动作之间的一个基本动作．由运动学分析证明了前手翻动作中的蹬摆腿，推手和翻转技术能够产生出较大的水平速度，通过制动起跳技术可以使水平速度快速转换，垂直速度迅速提高，从而保证了完成动作的质量和空翻动作之间的连接速度。     

我国优秀男子跳远运动员起跳中不同时相速度变化特征

采用现场定点高速摄影、影片解析及数理统计等研究方法。结果表明，我国优秀男子跳远运动员起跳缓冲阶段，身体重心水平速度减小，并与垂直速度增加之间存在密切关系；蹬伸阶段身体重心水平速度略有回升，垂直速度保持增加的态势，且离板瞬间身体重心水平速度和垂直速度都呈现出相对较大的趋势。     

Gymnastics

The 16 highest‐scored Roche vaults (G1) performed during the 2000 Olympic Games were compared with those receiving the 16 lowest‐scores (G2). A 16‐mm motion picture camera operating at 100 Hz recorded the vaults during the competition. The results of t tests (p < .05) indicated G1, compared to G2, had (a) shorter time of board support, greater normalised average upward vertical force and backward horizontal force exerted by the board, greater change in the vertical velocity while on the board, and greater vertical velocity at board take‐off, (b) comparable linear and angular motions in pre‐flight, (c) smaller backward horizontal impulse exerted by the horse, smaller loss of the horizontal velocity while on the horse, and greater horizontal and vertical velocities at horse take‐off, (d) greater height and larger horizontal distance of post‐flight, (e) higher body mass centre at knee release, and (f) higher mass centre, greater normalised moment of inertia, and smaller vertical velocity at mat touchdown. Therefore, gymnasts and coaches should focus on sprinting the approach; blocking and pushing‐off the take‐off board rapidly and vigorously; departing the board with a large vertical velocity; exerting large downward vertical force and small forward horizontal force from the handstand position while on the horse; departing the horse with large horizontal and vertical velocities; and completing the majority of the double salto forward near the peak of trajectory and releasing the knees above the top of the horse to prepare for a controlled landing.     

对我国优秀男子跳远运动员劳剑峰起跳技术的生物力学分析

对劳剑峰九运会决赛最佳跳次的技术录像进行解析,结合专项理论并与国外优秀运动员的技术统计数据对比,得出: 1. 适宜增加起跳阶段的水平速度损失率,从而加大腾起角度,使起跳离地瞬间的水平速度和垂直速度的匹配更加合理,是改善起跳效果和提高成绩的重要途径.2. 改善起跳阶段的技术,减小着地脚和起跳阶段的扇面角,增大离地角是技术改进的方向.3. 加强膝关节快速用力条件下的退让式收缩能力和克制性收缩力量是专项力量训练的重点.     

Techniques used in high-scoring and low-scoring 'Roche' vaults performed by elite male gymnasts

The 16 highest-scored Roche vaults (G1) performed during the 2000 Olympic Games were compared with those receiving the 16 lowest-scores (G2). A 16-mm motion picture camera operating at 100 Hz recorded the vaults during the competition. The results of t tests (p < .05) indicated G1, compared to G2, had (a) shorter time of board support, greater normalised average upward vertical force and backward horizontal force exerted by the board, greater change in the vertical velocity while on the board, and greater vertical velocity at board take-off, (b) comparable linear and angular motions in pre-flight, (c) smaller backward horizontal impulse exerted by the horse, smaller loss of the horizontal velocity while on the horse, and greater horizontal and vertical velocities at horse take-off, (d) greater height and larger horizontal distance of post-flight, (e) higher body mass centre at knee release, and (f) higher mass centre, greater normalised moment of inertia, and smaller vertical velocity at mat touchdown. Therefore, gymnasts and coaches should focus on sprinting the approach; blocking and pushing-off the take-off board rapidly and vigorously; departing the board with a large vertical velocity; exerting large downward vertical force and small forward horizontal force from the hand-stand position while on the horse; departing the horse with large horizontal and vertical velocities; and completing the majority of the double salto forward near the peak of trajectory and releasing the knees above the top of the horse to prepare for a controlled landing.     

Dynamics of the support leg in soccer instep kicking

Abstract

We aimed to illustrate support leg dynamics during instep kicking to evaluate the role of the support leg action in performance. Twelve male soccer players performed maximal instep kicks. Their motions and ground reaction forces were recorded by a motion capture system and a force platform. Moments and angular velocities of the support leg and pelvis were computed using inverse dynamics. In most joints of the support leg, the moments were not associated with or counteracting the joint motions except for the knee joint. It can be interpreted that the initial knee flexion motion counteracting the extension joint moment has a role to attenuate the shock of landing and the following knee extension motion associated with the extension joint moment indirectly contributes to accelerate the swing of kicking leg. Also, appreciable horizontal rotation of the pelvis coincided with increase of the interaction moment due to the hip joint reaction force on the support leg side. It can be assumed that the interaction moment was the main factor causing the pelvis counter-clockwise rotation within the horizontal plane from the overhead view that precedes a proximal-to-distal sequence of segmental action of the swing leg.     

Contribution of hand and foot force to take-off velocity for the kick-start in competitive swimming

This study examines the hand and foot reaction force recorded independently while performing the kick-start technique. Eleven male competitive swimmers performed three trials for the kick-start with maximum effort. Three force platforms (main block, backplate and handgrip) were used to measure reaction forces during starting motion. Force impulses from the hands, front foot and rearfoot were calculated via time integration. During the kick-start, the vertical impulse from the front foot was significantly higher than that from the rearfoot and the horizontal impulse from the rearfoot was significantly higher than that from the front foot. The force impulse from the front foot was dominant for generating vertical take-off velocity and the force impulse from the rearfoot was dominant for horizontal take-off velocity. The kick-start’s shorter block time in comparison to prior measurements of the grab start was explained by the development of horizontal reaction force from the hands and the rearfoot at the beginning of the starting motion.