我国优秀女子链球选手最后用力技术运动学特征的研究

通过三维运动学分析的方法,对我国现役的3名优秀女子链球运动员的投掷技术进行研究,发现王峥单支撑时间较短,身体转动快,右脚着地积极,上下肢扭紧情况好,下肢缓冲的幅度小,重心起伏程度小,最后用力中左腿撑蹬效果不好.廖晓燕的缓冲时间短,重心移动快,在水平方向速度小,垂直方向的速度大,上下起伏程度大,最后用力中存在右肩提前对器械加速的现象.张永莉单支撑时间长,缓冲时间长,右脚着地瞬间重心偏左,重心速度保持的不好,上下起伏程度较大,缓冲瞬间下肢缓冲幅度小,力量向前性不好等问题.     

我国女子铁饼优秀运动员过渡和最后用力阶段技术动力学及运动学的特征

时目前我国3名优秀女子铁饼运动员投掷技术进行同步研究发现,宋爱民存在腾空时间短、重心高、右脚着地早、上下肢扭紧差,最后用力阶段重心向投掷方向移动速度快、左右脚在垂直方向和前后方向的力较大、力量的向前行较好;孙太凤缓冲时间较短、右腿蹬伸充分、垂直方向和向前的力量较大;李艳凤过渡阶段上下肢扭紧好、身体后倾角度大、右脚着地对地面冲击力大、左右方向的力较大、力量在左右腿之间移动幅度大、没有转化为向前或者垂直方向的力量,向前性差,蹬伸不充分.     

我国优秀女子铅球运动员巩立姣最后用力技术的运动学分析

选定进入2013年全国田径大奖赛（苏州站）女子铅球决赛运动员巩立姣最后用力阶段技术为研究对象,研究结果显示：右侧技术中,右踝关节蹬伸比较积极,右膝角幅度大整个右侧各关节伸展比较充分;左侧技术中,左膝角偏小,蹬伸幅度、左膝关节缓冲幅度与世界优秀运动员一致;最后用力阶段各环节特征技术中,左脚着地瞬间身体重心速度、右髋速度、右肩速度都低于3位优秀运动员,而铅球出手瞬间右肩速度、右肘速度较强,另外最后用力出手瞬间,出手高度和出手速度都低于我国3位世界级优秀运动员相应指标。     

我国优秀男子铅球运动员投掷技术的运动学研究

采用运动生物力学研究方法,对现阶段我国4名优秀男子铅球运动员背向滑步推铅球技术进行研究.发现:刘×滑步过程中重心抬起幅度较大,上体过早上抬,减小超越器械的效果,过渡阶段刘×右侧下肢伸展幅度大,上体抬起过高,减小用力的距离,姚××过渡阶段上体抬起幅度大,增量大,右膝关节处压紧效果差,最后用力阶段王××右侧下肢髋、膝关节用力时机一致,协调性好,姚××踝关节伸展幅度小,蹬伸不积极,刘×膝关节处伸展幅度大,冯×右髋关节伸展速度慢,用力阶段主要以蹬伸下肢为主,协调用力差.     

优秀女子铅球运动员过渡阶段技术特征的运动学分析

以2009年第18届亚洲田径锦标赛女子铅球前6名运动员为研究对象,研究其过渡阶段的技术特征。结果表明：在过渡阶段刘相蓉右腿的蹬伸时间最长,其在过渡阶段身体重心移动的速度比较快,较早的进入了蹬伸阶段;巩立娇垂直速度的波动幅度最大为0.886 m/s;刘相蓉和瑞拉比在过渡阶段提前对铅球施力了,肩轴打开的时机过早,不利于躯干充分扭紧以及超越器械动作的形成;在过渡阶段右脚着地后,3名选手的左髋速度都大于右髋的速度,动作合理,但是3名运动员在左脚着地后,右髋的速度小于左髋的速度。     

对我国部分优秀女子背越式跳高运动员起跳技术的运动学分析

通过高速摄影对全国大奖赛女子跳高比赛前4名运动员的最后4步助跑技术进行3维运动学分析,得出中国运动员起跳时支撑腿蹬伸不充分,起跳脚着地至离地瞬间身体重心水平速度的转化率优于世界优秀运动员,起跳腿蹬伸离地瞬间髋、膝、踝3关节都没有充分伸展等研究结果。     

短跑支撑阶段运动生物力学分析

采用测力、高速录像及特殊的数据平滑处理方法研究短跑运动员途中跑技术的运动学和动力学特征,进行田径技术原理的探索。结果表明,支撑时期可以分为着地阶段和蹬伸阶段,蹬伸阶段可分前蹬,后蹬前段,后蹬后段。途中跑前蹬段是人体重心垂直方向向上加速的重要时刻,前蹬时下肢一定程度的垂直加速用力虽影响水平速度,但对提高垂直速度有积极意义,前蹬和后蹬前段是身体重心垂直向上加速运动的阶段。着地缓冲后的前蹬用力也是实现良好成绩的技术之一。途中跑着地和前蹬阶段失去的水平速度损失完全可以从后蹬中得到补充。着地点过近对前支撑阶段获得重要的垂直速度不利,支撑阶段离地前的20ms身体重心速度已经开始下降。     

我国优秀女排队员接发球技术的三维运动学比较分析

一传到位率偏低和失误率较高是新一届中国女排亟待解决的主要问题之一。通过三维高速录像分析,揭示了我国4名优秀女排运动员接跳飘球技术动作的运动学特征。周苏红和张娴的动作具有移动判断准确,击球点在体前低于身体重心,下肢蹬伸用力幅度小,手臂上抬幅度较大的特点;杨昊和殷茵的动作具有移动判断不够准确,击球点在体侧高于身体重心,下肢蹬伸用力幅度大,手臂上抬幅度大的特点。研究认为移动判断准确,击球点低于身体重心,上下肢协调蹬伸用力有利于提高接发球的到位率。     

全国第10届运动会男子标枪运动员最后用力技术的运动学分析

掷标枪的最后用力是标枪技术中最重要的环节,是整个掷标枪过程中的灵魂与核心.通过对全国第10届运动会男子标枪决赛前8名运动员最后用力的运动学研究,结果表明,运动员制动脚着地的单、双支撑时间较长,投掷侧与异侧的速度不均衡,下肢蹬伸力量相对薄弱,身体重心高度变化较大,两脚支撑距离相对较小,以致影响了出手速度,最终导致运动成绩不理想.     

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。     

对我国优秀女子标枪运动员最后用力阶段右肩与右髋速度特征的三维运动学分析

运用三维运动学分析方法对参加第 13届亚运会的我国 6名优秀女子标枪运动员的最后用力阶段的技术动作进行解析 ,结果表明 :最后用力阶段右髋动作加快与制动的时机不甚理想 ,躯干相关肌群有过早收缩发力的现象 ,从而影响右肩速度的变化 ;发现右肩速度超过右髋速度的时机也不理想 ,右肩与右髋的动量传递效果与右脚的拖拉制动动作连接不紧 ,以至减小了最后用力的效果     

Athletics

The purposes of this study were to investigate (1) the relationships between official distance and selected ground reaction measures during discus throwing; and (2) the relationships between selected ground reactions and selected lower extremity joint kinetics. Three high‐speed video cameras and three force plates were used to collect three‐dimensional videographic and force plate data in this study. An inverse dynamic model was used to determine the lower extremity kinetics. Multiple regression analyses were conducted to determine relationships of the selected kinematic and kinetic measures with the official distance. Official distance was significantly correlated with ground reaction forces on the left foot during the first single‐support phase, on the right foot during the second single‐support phase and delivery phase, and on the left foot during the delivery phase. Also, the right‐hip extension and internal rotation moments and left‐knee extension moment during the delivery phase were significantly correlated with official distance. These results suggest that discus throwers should drive vigorously forward during the first single‐support phase and increase the landing impact force on the right foot after flight. Also they should increase forward and rightward ground reaction force on the right foot and backward and vertical force on the left foot by powerful right‐hip extension and internal rotation and left‐knee extension during the delivery phase. These results provide critical information regarding the training of discus‐throwing techniques, and the direction of future biomechanical studies on this event.     

The influence of cricket fast bowlers’ front leg technique on peak ground reaction forces

Abstract

High ground reaction forces during the front foot contact phase of the bowling action are believed to be a major contributor to the high prevalence of lumbar stress fractures in fast bowlers. This study aimed to investigate the influence of front leg technique on peak ground reaction forces during the delivery stride. Three-dimensional kinematic data and ground reaction forces during the front foot contact phase were captured for 20 elite male fast bowlers. Eight kinematic parameters were determined for each performance, describing run-up speed and front leg technique, in addition to peak force and time to peak force in the vertical and horizontal directions. There were substantial variations between bowlers in both peak forces (vertical 6.7 ± 1.4 body weights; horizontal (braking) 4.5 ± 0.8 body weights) and times to peak force (vertical 0.03 ± 0.01 s; horizontal 0.03 ± 0.01 s). These differences were found to be linked to the orientation of the front leg at the instant of front foot contact. In particular, a larger plant angle and a heel strike technique were associated with lower peak forces and longer times to peak force during the front foot contact phase, which may help reduce the likelihood of lower back injuries.     

Technique factors related to ball release speed and trunk injuries in high performance cricket fast bowlers

In this study we analysed technique, ball speed and trunk injury data collected at the Australian Institute of Sport (AIS) from 42 high performance male fast bowlers over a four year period. We found several notable technique inter-relationships, technique and ball speed relationships, and associations between technique and trunk injuries. A more front-on shoulder alignment at back foot contact was significantly related to increased shoulder counter-rotation (p < 0.001). Bowlers who released the ball at greater speeds had an extended front knee, or extended their front knee, during the front foot contact phase (p < 0.05). They also recorded higher braking and vertical impact forces during the front foot contact phase and developed those forces more rapidly (p < or =0.05). A maximum hip-shoulder separation angle occurring later in the delivery stride (p = 0.05) and a larger shoulder rotation to ball release (p = 0.05) were also characteristics of faster bowlers. Bowlers suffering lower back injuries exhibited typical characteristics of the 'mixed' technique. Specifically, the hip to shoulder separation angle at back foot contact was greater in bowlers who reported soft tissue injuries than in non trunk-injured bowlers (p = 0.03), and shoulder counter-rotation was significantly higher in bowlers who reported lumbar spine stress fractures than non trunk-injured bowlers (p = 0.01). The stress fracture group was also characterised by a larger hip angle at front foot contact and ball release, whereas a more flexed front knee at ball release characterised the non trunk-injured group.     

Changes in ankle work,foot work,and tibialis anterior activation throughout a long run

BackgroundThe ankle and foot together contribute to over half of the positive and negative work performed by the lower limbs during running. Yet, little is known about how foot kinetics change throughout a run. The amount of negative foot work may decrease as tibialis anterior (TA) electromyography (EMG) changes throughout longer-duration runs. Therefore, we examined ankle and foot work as well as TA EMG changes throughout a changing-speed run.MethodsFourteen heel-striking subjects ran on a treadmill for 58 min. We collected ground reaction forces, motion capture, and EMG. Subjects ran at 110%, 100%, and 90% of their 10-km running speed and 2.8 m/s multiple times throughout the run. Foot work was evaluated using the distal rearfoot work, which provides a net estimate of all work contributors within the foot.ResultsPositive foot work increased and positive ankle work decreased throughout the run at all speeds. At the 110% 10-km running speed, negative foot work decreased and TA EMG frequency shifted lower throughout the run. The increase in positive foot work may be attributed to increased foot joint work performed by intrinsic foot muscles. Changes in negative foot work and TA EMG frequency may indicate that the TA plays a role in negative foot work in the early stance of a run.ConclusionThis study is the first to examine how the kinetic contributions of the foot change throughout a run. Future studies should investigate how increases in foot work affect running performance.     

距骨下关节功能解剖和运动研究进展

运用文献资料调研和归纳与演绎等方法,以足部运动中重要而又相对较少受到重视的距骨下关节为研究对象,从距骨下关节的功能解剖结构、运动种类、在下肢运动中的作用和研究距骨下关节运动的方法等角度综述了国内、外在该领域的研究进展,以期为足部损伤防护和运动鞋研发等提供参考建议。研究认为:距骨下关节承受并传导人体重量,协调踝关节运动,是后足生物力学的中心和足部稳定的重要枢轴结构。其与踝关节、膝关节的协同一致性在人体活动尤其奔跑、跳跃时具有重要意义。协同性缺乏易导致足部以至整个下肢肌肉骨骼的损伤。距下关节功能的丧失,将使跟骨内收、外展活动度减小,踝关节对后足内外翻运动做出代偿,而这种代偿是有限的、非生理性的,对日常的行走功能来说尚可适应,但不能满足运动员对奔跑、跳跃、地面不平等功能运动的特殊要求。因此,了解距下关节的解剖和运动特点有助于认识足踝部隐匿性损伤,正确评价运动员的足踝及下肢功能。     

A kinetic analysis of discus-throwing techniques

The purposes of this study were to investigate (1) the relationships between official distance and selected ground reaction measures during discus throwing; and (2) the relationships between selected ground reactions and selected lower extremity joint kinetics. Three high-speed video cameras and three force plates were used to collect three-dimensional videographic and force plate data in this study. An inverse dynamic model was used to determine the lower extremity kinetics. Multiple regression analyses were conducted to determine relationships of the selected kinematic and kinetic measures with the official distance. Official distance was significantly correlated with ground reaction forces on the left foot during the first single-support phase, on the right foot during the second single-support phase and delivery phase, and on the left foot during the delivery phase. Also, the right-hip extension and internal rotation moments and left-knee extension moment during the delivery phase were significantly correlated with official distance. These results suggest that discus throwers should drive vigorously forward during the first single-support phase and increase the landing impact force on the right foot after flight. Also they should increase forward and rightward ground reaction force on the right foot and backward and vertical force on the left foot by powerful right-hip extension and internal rotation and left-knee extension during the delivery phase. These results provide critical information regarding the training of discus-throwing techniques, and the direction of future biomechanical studies on this event.     

铅球最后用力的理论与训练

在对铅球最后用力概念界定的基础上，重新划分铅球最后用力阶段，并论述了单支撑最后用力的积极意义及专项力量的训练。通过对大量文献资料进行数理统计和综合分析，提出了划分铅球最后用力阶段的新观点：推铅球最后用力阶段，是从滑步过程中支撑腿水平方向上运动结束之时开始到铅球离手的过程。整个最后用力阶段分为单支撑用力和双支撑用力出手两个阶段，单支撑最后用力阶段对减小铅球预先速度的损耗、加快左脚着地和拉长工作肌有重要意义。在训练中采用切割组合训练方法可有效地把力量与技术紧密的结合在一起，加强快速力量训练，尤其下肢爆发力和制动力量。