对我国优秀男子铁饼运动员投掷技术的运动学分析

通过对我国优秀男子铁饼运动员旋转掷铁饼技术的速度结构特征和动作结构特征的初步分析,发现我国男子铁饼运动员与国外优秀运动员的主要差距是双支撑起转阶段和旋转阶段铁饼的速度损失较大。腾空和过渡时间长、肩髋柔韧性差、最后用力时机晚等是影响我国运动员铁饼速度发挥的主要因素。     

对篮球比赛中执行罚球时的心理状态及训练方法的研究

罚球是篮球比赛中得分的一个组成部分,罚球命中率的高低对篮球比赛胜负影响很大。通过对罚球时各种心理状态进行剖析,从而找出影响罚球命中率的各种因素及最佳训练模式,为教练员训练提供理论依据。     

The relationship between discus throwing performance and combinations of selected technical parameters

The aim of this study was to determine the relationship between discus throwing performance and the following technical parameters: hip–shoulder and shoulder–arm separation, trunk forward–backward tilt, throwing-arm elevation angles, and the absolute and relative throwing procedure phase times. Videographic data of 51 male and 53 female discus throwers' competitive performances were captured during major meets. The three-dimensional coordinates of 21 body landmarks and the discus were obtained for each thrower's best trial using direct linear transformation. The technical parameters were reduced from the three-dimensional data at six critical instants during the throwing procedure. Hierarchical stepwise multiple regression analyses were performed to determine the relative influence of linear combinations of the technical parameters on discus throwing performance. Specific techniques associated with linear combinations of certain technical parameters were identified using canonical correlations. Males and females were analysed separately. Suggestions for controlling the height of release and the vertical component of the speed of release using an effective technique are made.     

Timing of ball release in overarm throws affects ball speed in unskilled but not skilled individuals

We tested the hypothesis that variability in the timing of ball release in overarm throws affects ball speed. Nine unskilled and six skilled throwers made 30 throws fast and accurately from a sitting and standing position. Angular positions of finger and arm segments were recorded with search-coils at 1000 Hz; ball speed was measured with a radar gun. The time of ball release from the fingertips was measured with respect to seven arm kinematic reference points. Mean timing windows for ball release were 28?ms for unskilled throwers and 7?ms for skilled throwers. Mixed-model analyses of variance showed that a there was a statistically significant relationship between ball speed and the timing of ball release in unskilled throwers, but not in skilled throwers. This was presumably due to the difference in variability of the timing of ball release between the two groups. In contrast, skilled throwers showed a relationship between ball speed and peak forearm angular velocity (one measure of arm speed). We conclude that although variability in the timing of ball release can affect ball speed, this is only a major factor in unskilled throwers. When skilled throwers throw fast, variability in ball speed is due to variability in arm speed.     

不同瞄准点训练对篮球罚球命中率影响的实验研究

运用实验法,对罚球时选择不同瞄准点训练后命中率的变化进行对比分析。结果表明,经过分组训练,有确定瞄准点的实验组训练后罚球命中率具有显著提高,而没有确定瞄准点的实验组训练后命中率提高不明显。其中,以篮圈后沿为瞄准点的实验组训练后罚球命中率提高最大,而以篮圈前沿为瞄准点的实验组命中率提高次之,选择篮圈中心和没有固定瞄准点的对照组训练后罚球命中率增加不明显。     

多金属低贫矿石跳汰预选抛废试验研究

为了充分利用丰富的＂无开采价值＂低贫矿石资源,延长矿山服务年限,文章试验采用锯齿波跳汰机对多金属低贫矿石进行预选抛废研究,并取得了较佳的试验综合指标：预选抛废率高达61.24%;精矿富集比铅2.47、锌2.42、锡2.68;总金属回收率铅89.35%、锌85.88%、锡90.37%。项目成果为提高选厂主选流程的入选品位和原矿生产能力,实现低成本大规模生产创造了良好的前提条件。     

掷标枪运动专项技术与专项力量训练现状研究

通过对掷标枪运动专项技术与专项力量训练现状的研究,得出：最后用力阶段是掷标枪专项技术与力量相结合的训练重点,对标枪技术起稳定作用和对爆发式用力起协调作用的基础力量同样重要;专项技术与专项力量训练相结合的力度不够,众多的训练方法过于陈旧和单调。     

中国女子标枪竞技水平停滞不前的主要因素及对策研究

采用文献资料法、数据统计法,对中国女子标枪竞技水平停滞不前的主要因素进行剖析。结果表明：在大型比赛中发挥不出应有水平;比赛能力较差;一般身体素质和专项能力上与世界优秀运动员存在较大差距等因素制约中国女子标枪发展。针对这些问题提出对策：延长运动员的运动生命、多参加国际比赛,积累比赛经验,提高一般身体素质和专项能力上的潜力,针对中国运动员身材特点和素质情况,确定技术模式和改进训练方法等,以期为中国女子标枪项目的良性发展提供理论依据。     

北京奥运会女子链球铜牌得主张文秀投掷技术的运动学研究

女子链球是我国田径中的优势项目,张文秀在2008年北京奥运会上获得了一枚铜牌,实现了我国在该项目历史性的突破。通过文献资料和三维运动学分析的方法,对我国优秀女子链球运动员张文秀的投掷技术进行研究发现,她的旋转技术存在一定不合理现象,单支撑时间长于双支撑时间,双支撑时间偏短,优点是旋转过程中对器械逐渐加速的能力强,旋转加速节奏和加速时机把握得较好,符合现代掷链球的技术要求。通过对她的投掷技术进行诊断分析,旨在为她技术改进提供帮助,推动我国该项目更上一个台阶。     

基于Ariel三维解析系统对于链球投掷技术分析的基本方法

运用三维影像解析的方法对于动作技术进行生物力学分析的关键在于,充分熟悉与掌握三维影像解析系统的操作、动作技术诊断指标的提取,以及动作技术评价的方法.文章以链球投掷技术分析为范例,介绍了Ariel三维解析系统分析动作技术的方法.