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本文通过录像解析的研究方法，对跳远全程助跑、全程助跑起跳与完整跳远进行运动学比较。结果表明：全程助跑不起跳练习手段因与完整跳远助跑技术动作存在较大的运动学差异，且割裂了助跑与起跳结合这一跳远的核心关键技术部分，所以不应采用该手段作跑练习的方法；全程助跑起跳练习手段与完整跳远的相应技术部分的运动学数据相近，且专项强度更高，所以可作专项练习手段。 相似文献
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Debbie Risius Alexandra Milligan Jason Berns Nicola Brown 《Journal of sports sciences》2017,35(9):842-851
To assess the effectiveness of breast support previous studies monitored breast kinematics and kinetics, subjective feedback, muscle activity (EMG), ground reaction forces (GRFs) and physiological measures in isolation. Comparing these variables within one study will establish the key performance variables that distinguish between breast supports during activities such as running. This study investigates the effects of changes in breast support on biomechanical, physiological and subjective measures during running. Ten females (34D) ran for 10 min in high and low breast supports, and for 2 min bare breasted (2.8 m·s?1). Breast and body kinematics, EMG, expired air and heart rate were recorded. GRFs were recorded during 10 m overground runs (2.8 m·s?1) and subjective feedback obtained after each condition. Of the 62 variables measured, 22 kinematic and subjective variables were influenced by changes in breast support. Willingness to exercise, time lag and superio-inferior breast velocity were most affected. GRFs, EMG and physiological variables were unaffected by breast support changes during running. Breast displacement reduction, although previously advocated, was not the most sensitive variable to breast support changes during running. Instead breast support products should be assessed using a battery of performance indicators, including the key kinematic and subjective variables identified here. 相似文献
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运用文献资料法、三维定点摄像法、影像解析法等，以刘虹参加2016年全国竞走大奖赛暨奥运选拔赛20km比赛的技术特征为研究对象，对其技术的优缺点进行归纳总结，旨在为其里约奥运会技术改进提供参考。结果表明：总体来看刘虹技术的规范性、实效性特征较好。技术规范性特征具体表现为其腾空时限处于模糊腾空时限内，但是最后冲刺阶段由于提速导致腾空时限远超过临界值。头顶垂直位移稍偏大，摆动腿离地瞬间膝角偏小，垂直膝关节角度同样偏小，且重心移动速度越快，其膝角越小，易形成“跑”的动作表象。着地技术符合裁判员判罚的直腿标准，且垂直支撑阶段“反弓”动作明显。实效性特征表现为左、右步长均有提高，“小步高频”的中国技术风有较大改观；但仍存在左、右不均衡现象。两大腿夹角偏小，说明刘虹向前“送髋”的技术仍需改进。 相似文献
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张勇 《西安体育学院学报》2008,25(5)
通过对三级跳远两名国家队集训运动员比赛现场拍摄，针对三级跳远技术过程中重要环节的运动学、动力学参数分析，在揭示技术体系内部构建因素关联的基础上，分析我国三级跳远运动员与世界级运动员技术环节上存在的差异。 相似文献
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文章以摇杆滑块机构滑块沿任意曲线做匀速运动为目标,首先建立相应的矢量方程式并进行求解,接着又用Pro/E软件建立简单骨架模型进行仿真分析,研究方法及获得结果为进一步研究机构铰链处驱动电机的控制方法提供了一定的依据。 相似文献
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Dynamical analysis of winter terrain park jumps 总被引：1，自引：1，他引：0
Jump features in winter terrain parks frequently pose a hazard to patrons and may represent a significant liability risk to
winter resorts. By performing a simple dynamic analysis of terrain park jumps, the relative risk to impact injuries for any
proposed jump design can be quantified thereby allowing terrain park designers to minimize the risk from this class of injury. 相似文献
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文章介绍了一种伸缩杆-水平滑块式三自由度并联机器人机构，根据该机构的结构建立了其运动学方程导出其雅可比矩阵，并对该机构的静力学方程进行了推导。该机器人机构运动学方程正、逆解均具有显式解；其雅可比矩阵在工作空间内不存在奇异点；具有三个平动方向的运动自由度，是一种具有实用价值的机器人机构。 相似文献
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选取李玲在2008年全国田径大奖赛萧山站女子撑竿跳高决赛4.45m夺冠时的比赛录像,运用德国SIMI Mo-tion影像解析系统进行分析,并与国内外优秀撑竿跳高运动员技术进行比较研究。研究结果表明：①李玲的最后两步助跑,倒2步步长偏短,且其倒1步比倒2步步长长,出现了＂拉大步＂现象。②李玲起跳时上手握点地面投影点和起跳点的间距较大,与现代撑竿跳高的技术要求略有偏差。③起跳的腾起角度、竿弦与地面的夹角较小,已达到世界级优秀运动员水平。④起跳时间偏长,插穴时间过早,与＂自由起跳＂技术尚有差距。⑤起跳步水平速度损失、垂直速度增加都较小,是比较合理的起跳技术,但最后两步助跑的水平速度不够。 相似文献
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Vassilios Gourgoulis Nickos Aggelousis Giorgos Mavromatis Athanasios Garas 《Journal of sports sciences》2013,31(8):643-652
We investigated the linear kinematics and the change in energy of the barbell and the angular kinematics of the trunk and leg during the snatch technique of 12 elite male Greek weightlifters under competitive conditions after the new weight classification. Two S-VHS cameras operating at 60 Hz were used to record the lifts. The spatial coordinates of selected points were calculated using the direct linear transformation procedure; after digital filtering of the raw data, the angular displacements and angular velocities were calculated for the hip, knee and ankle joints. The following variables were also calculated for the barbell: vertical and horizontal displacement, vertical linear velocity and acceleration, external mechanical work and power output. The results revealed that all weightlifters flexed their knees during the transition phase, independently of their weight category. This indicates that the athletes use the elastic energy produced during the stretch–shortening cycle to enhance their performance. In nine athletes, we found that the barbell trajectory did not cross a vertical reference line that passed through the initial position of the barbell. The vertical linear velocity of the barbell was increased continuously from the beginning of the movement until the second maximum extension of the knee joint, with no notable dip being observed. Regarding the change in energy of the barbell, we found that the mechanical work for the vertical displacement of the barbell in the first pull was significantly greater than the mechanical work in the second pull. In contrast, the estimated average mechanical power output of the athletes during the vertical displacement of the barbell was significantly greater in the second pull than in the first pull. We conclude that the major elements of the snatch technique of elite Greek weightlifters have not been aff ected by the new weight classification. 相似文献