我国优秀标枪运动员陈奇投掷步技术特点分析

采用高速摄像、录像解析及比较分析方法,对我国优秀标枪运动员陈奇投掷步相关运动学参数进行比较分析。结果发现陈奇投掷步的技术特点:助跑距离较长、助跑速度较快,第二交叉步前后速度损失同投掷成绩呈负相关;第一交叉步前后身体重心速度的增加幅度同交叉步前后躯干后倾角变化量呈负相关,第二交叉步前后身体重心速度的损失幅度同交叉步前后躯干后倾角变化量呈负相关;最后一步前后身体重心水平速度的损失幅度同躯干后倾角变化量呈正相关。     

The effects of localised fatigue on upper extremity jump shot kinematics and kinetics in team handball

Team handball is a popular sport worldwide that requires numerous throws to be made throughout the course of a game. Because of the upper extremity demands of repetitive throwing, it is possible that fatigue can alter the mechanics of a shot. The purpose of this study was to determine the influence of localised fatigue on jump shot kinematics and kinetics. Eleven male team handball players (23.1 ± 3.1 years; 185.1 ± 8.3 cm; 89.7 ± 12.2 kg) volunteered. An electromagnetic tracking system was used to examine the jump shot prior to and following localised fatigue. The fatiguing protocol consisted of throwing a 2.2 kg medicine ball into a rebounder until volitional fatigue. No significant kinematic or kinetic differences were observed following fatigue. Shoulder external rotation was ?74.8 ± 14.9° prior to and ?79.0 ± 14.7° following fatigue at MER. Scapula, external rotation at ball release (BR) prior to fatigue was ?2.2 ± 7.0° and ?3.2 ± 11.1° following fatigue. Scapular internal rotation, at maximum shoulder internal rotation (MIR), changed from 18.4 ± 11.2° to 20.4 ± 11.8°. Ball velocity decreased from19.8 m · s^–1 to 18.8 m · s^–1 (P = 0.12). Accuracy percentage in the pre-fatigue trials was 60.8 ± 14.1% and 52.8 ± 12.7% following fatigue (P = 0.20). While no significant changes were observed, it is possible that other fatiguing protocols that more closely represent the aerobic and throwing demands of the sport may have a greater effect on the kinematics and kinetics of the jump shot.     

第28-32届奥运会投掷项目运动员年龄特征发展趋势研究

通过文献资料法、数理统计法、对比分析法以及个案分析法对第28-32届奥运会投掷项目前12名运动员的竞技年龄从结构、性别、年龄特征等角度进行对比分析。结果表明:(1)在28-32届奥运会投掷项目中,25-30岁年龄段运动员一直是奥运会投掷项目的主力军,在1-3名以及1-12名的人数占比中,一直呈增长趋势; 31岁以上年龄段运动员对奖牌仍具有较强的竞争力,在1-3名的人数占比中,整体呈现出增长的趋势。(2)在近5届奥运会中,投掷项目在整体上1-12名运动员平均年龄呈下降趋势;前3名运动员平均年龄发展呈现出增长趋势,女子运动员的平均年龄普遍低于男子运动员。(3)投掷运动员最佳竞技年龄表现出铁饼>链球>标枪>铅球(29> 28> 27.5> 27)的现象。(4)随着科技的助力以及科学的训练理念和方法的普及,国内外部分高水平投掷运动员能够较长时间的保持个人最佳竞技状态。     

影响中国女子冰壶队投壶成功率因素分析

本文运用文献资料法、录像观察法和数理统计法,对影响中国女子冰壶队投壶成功率进行分析,结果表明：技战术水平高低是关键因素;心理素质是另一主要因素;魔鬼赛程是影响投壶成功率的另一障碍因素。     

论最后用力在掷标枪技术中的重要作用

标枪投掷中,最后用力的好坏直接影响到运动成绩,在分析了各环节的基础上提出了最后用力在标枪投掷中的重要作用。而在最后用力技术环节中,左侧支撑技术的好坏,直接影响力的传递和用力的效果,进而影响投掷成绩。     

体育运动中抛物体问题研究的基本方法

基于抛物体运动规律对两类典型的抛物体运动（投掷项目、篮球投篮）进行了分析。在投掷项目中,投掷器械的飞行远度作为目标函数,在Excel中计算了不同的出手速度（V0）、出手角度（θ）及出手高度（H）对器械飞行远度的影响;在篮球运动中,以投篮的最小速度角和最小进篮误差作为目标函数,计算了不同的投篮距离、出手高度的情况下,投篮的最佳出手角度,寻找出篮球投篮最佳出手角的变化规律以便于运动员在实践中掌握和运用,提高投篮的命中率。     

Is movement variability important for sports biomechanists?

This paper overviews the importance for sports biomechanics of movement variability, which has been studied for some time by cognitive and ecological motor skills specialists but, until quite recently, had somewhat been overlooked by sports biomechanists. The paper considers biomechanics research reporting inter- and intra-individual movement variability in javelin and discus throwing, basketball shooting, and locomotion. The overview does not claim to be comprehensive and we exclude such issues as the theoretical background to movement and coordination variability and their measurement. We overview evidence, both theoretical and empirical, of inter-individual movement variability in seeking to achieve the same task goal, in contrast to the concept of “optimal” movement patterns. Furthermore, even elite athletes cannot reproduce identical movement patterns after many years of training, contradicting the ideas of motor invariance and “representative” trials. We contend that movement variability, far from being solely due to neuromuscular system or measurement “noise” – as sports biomechanists may have previously supposed – is, or could be, functional. Such functionality could allow environmental adaptations, reduce injury risk, and facilitate changes in coordination patterns. We conclude by recommending that sports biomechanists should focus more of their research on movement variability and on important related topics, such as control and coordination of movement, and implications for practice and skill learning.     

论资本市场信息披露机制的建设

在资本市场上，信息披露是投资者了解上市公司、证券监管机构监管上市公司的主要途径，信息披露制度是各国证券法律制度的重要原则。资本市场信息披露机制建设的基本理论依据是“有效资本市场理论”。美国、法国等西方发达国家资本市场信息披露机制建设的经验可以给我们很好的启发。资本市场信息披露机制的建设首先要进一步完善法律建设，其次要进一步完善执法体系，第三要进一步完善公司的治理结构，第四要进一步完善政府监管模式。     

中国女子垒球优秀投手投球动作的生物力学研究

对中国目前国内三位女子优秀垒球投手绕环投球动作进行三维定点拍摄和录像解析.实验结果表明中国优秀投手对整个投球动作的总体掌握较熟悉,动作连贯性较好.其中张艳清伸踏时间、下摆加速时间、伸踏距、肩髋角、肘伸速度、肩旋内速度、球出手速度等运动学指标已达国际一流水平.在出手瞬间人体重心高度、球心高度方面,三位投手没有显著性差异,两指标值说明我国优秀运动员对垒球出手环节技术的掌握已达到国际先进水平.     

奥运会男子投掷项目成绩发展趋势及对策研究

对历届奥运会男子铅球、铁饼、标枪最好成绩增长值和增长率的分析，结合曲线回归拟和就短期发展趋势进行了预测，进而从一个角度对制定中国奥运发展战略提出建议。