Gender Differences in Children's Throwing Performance: Biology and Environment

Abstract

This study evaluated the influence of biological and environmental variables on the differences between the throwing performance of 5-year-old girls and boys. A total of 100 children (48 girls, 52 boys) were tested on throwing for distance and rated on two components of throwing form—trunk rotation, and foot action. Children were evaluated on eight biological characteristics—height, weight, body mass index, ponderal index, sum of four skinfolds, body diameters, arm and leg girths, and somatotypes—and four environmental characteristics—older brother, older sister, presence of adult male, and playing with older children. Results indicated that boys threw farther than girls and exhibited more mature form. Boys had greater joint diameters than girls, a smaller sum of four skinfolds, and more estimated arm muscle. Boys were more likely to play regularly with older children. Girls' throwing performance was only 57% that of boys, but when throwing was adjusted for a linear composite of biological variables, girls' throwing performance increased to 69% of boys'. Thus, while the differences in most motor performance tasks between boys and girls prior to puberty have been attributed to environmental factors, some of the differences in throwing performance appears to reflect biological characteristics, even as early as 5 years of age.     

Longitudinal Change in Throwing Performance: Gender Differences

Abstract

Twenty-four male subjects were used to study effects upon successive hand reaction times when the interval between paired visual stimuli was manipulated over the range 50 to 1,000 mseconds. Subjects were divided into fast and slow groups on the basis of well-practiced simple reaction time measures. Results indicated that both simple reaction time and initial paired response reaction time were unrelated to delays in the second response due to the psychological refractory period. It was suggested that a serious reappraisal of the single channel response system theory merits consideration and that ability to execute fast, consecutive paired responses may represent a new component in motor skills.     

链球运动成绩影响因素的分析

链球出手后在空中所做的运动为抛物体运动,影响抛物体远度的主要因素为:出手速度、出手角度、出手高度。主要运用数学的方法计算出手速度、角度、高度时于运动成绩的影响,并对于影响链球运动成绩的诸多因素进行了分析,以帮助教练员与运动员在链球运动实践中把握动作技术的关键。     

我国女子链球运动水平现状的分析

通过对第四届全国城运会女子掷链球比赛的现场调查访问与测试 ,从参赛者的年龄、身体形态、训练年限以及投掷技术形式和成绩等方面分析了我国女子掷链球运动水平的现状与发展趋势。其结果可对女子掷链球这一新项目今后的训练和比赛产生积极的影响。     

掷铁饼运动的历史沿革和发展趋势研究

本文通过文献资料法对掷铁饼运动的起源、发展趋势进行了系统的分析与论述。结果显示：掷铁饼运动起源于人类早期的生产劳动;掷铁饼技术大致经历原地投掷、上步投掷、侧向旋转投掷以及背向旋转投掷几个阶段;将来掷铁饼技术的发展趋势为：继续提高器械出手速度并保持良好的出手初始状态,加快和完善旋转技术,加强旋转与最后用力的衔接连贯,充分发挥基本技术原理与个人特点的完美结合。     

Competition and Instructional Set Effects On the Speed and Accuracy of a Throwing Task

Abstract

Two experiments were conducted to investigate the effects of competition and instructional sets on the speed and accuracy of a dart-throwing task. In both experiments individuals competed against another subject on one day, and performed under noncompetitive conditions on a second day. The five distinct instructional sets varied from extreme emphasis on speed to extreme emphasis on accuracy. Multivariate analyses of variance revealed main effects for instructional sets on speed and accuracy in both experiments. Strong tradeoffs occurred with speed slowing and accuracy improving as the instructional emphasis changed from speed to accuracy. A competition by instructional sets interaction in Experiment 2 indicated that competition facilitated speed when speed was important, but when instructions emphasized accuracy, speed was slower in competition than in noncompetition. Accuracy was not affected by competition.     

对我国优秀标枪运动员投掷步技术的研究

本文通过对我国优秀标枪运动员和世界优秀标枪运动员投掷步技术的分析与对比,结果发现：我国男子标枪运动员投掷步第1、2步躯干后倾角过大,第2～3步躯干后倾角变化幅度相对较小,以至于交叉步的动作速度及幅度受到影响;女子标枪运动员交叉步下肢前移幅度过小,影响躯干相关肌群收缩;我国男女运动员投掷步第4步都存在躯干后倾角下降较大,左膝弯屈角较小,左侧支撑无力的共性特征。     

重新认识投掷项目在十项全能运动中的地位——兼对各单项实际增分率的比较研究

本文针对新评分法执行以来,国际上全能运动出现徘徊局面,以及“投掷项目增分率低,得分难”的倾向性理论,结合当今世界上各单项的技术发展水平,以新评分表为参照系,着重于各单项实际增分率的深层探讨。研究发现,投掷项目的实际增分率处于中、上水平,为我国全能运动的发展和赶超世界水平提供理论依据。     

标枪“最后用力”的技术分析

论述了掷标枪技术中“最后用力”的实质及身体各部位在最后用力过程中的作用;指出了“最后用力”与“原地投掷”是两个不同的概念;提出了“提高力量利用率”的投掷观念.     

投掷手榴弹技术的运动学分析

本文应用运动生物力学影像测试图数分析方法研究投掷手榴弹中肱骨骨折问题。实验测试共进行3次(两次实弹投掷,一次实验室模拟测试),测试数据表明:投掷姿势不正确是造成肱骨螺旋性骨折原因之一,特别应注意投弹臂的肘部一定要在引臂时从肩后往上翻。经常纠正士兵的错误姿势能避免或减少骨折现象出现。     

掷标枪时的速度叠加效应及其训练

该文运用有关理论原理和方法,探析了掷标枪时的速度叠加效应,指出这是提高掷标枪运动成绩的有效途径。     

快速抛击练习对提高棒球击球能力的探讨

本文就快速抛击练习对提高棒球击球能力的作用及训练方法进行了分析探讨。     

论少年投掷运动员训练后的疲劳与恢复

文章对少年投掷运动员疲劳产生的原因及采用的有效恢复手段和方法进行了论述,以期对更加科学合理地制定少年投掷训练计划和参加比赛有一定的参考价值。     

对投掷男子新型标枪身体环节和出手参数的评价

用红湖16mm 高速摄影杋拍摄310名中国优秀男子标枪运动员试掷的技术动作。为了对各参数间的关系进行深入和全面的研究,利用路径分析方法对解析得出的身体环节和出手的运动学参数进行评价.结果表明:身体各主要环节速度之间、身体各环节和出手参数与投掷远度之间存在复杂的相互影响的关系.     

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。     

投弹骨折的力学机理的研究

应用经典力学结合实验测试的方法,研究战士投弹训练中出现的肱骨骨折现象。研究表明,投弹骨折的发生与投弹姿势不正确有关,前臂运动的角加速度、角速度及肘部加速度过大,都可能造成损伤,特别是这些参数最大值同时出现(一般易发生在制动时段),是发生骨折最危险的时刻。     

对重庆市大学生投掷项目水平的调查研究

通过文献资料法、调查法,对重庆市第一届大学生运动会中短跑类、跳跃类、投掷类项目各项前12名达运动技术等级的比较,以及本次运动会最好成绩所达到的运动技术等级、前12名平均成绩所达到的运动技术等级的调查,分析基层投掷项目水平现状并提出解决的对策,为今后基层投掷项目体育后备人才的培养提供参考。     

奥运会田径项目成绩发展趋势及灰色预测研究

以历届奥运会田径比赛各项最好成绩为基础 ,利用灰色理论的GM (1,1)模型方法探讨了奥运会田径项目的发展变化趋势。结果显示 ,从总的趋势看 ,奥运会的各田径项目都呈发展上升趋势 ;从第 2 0届以后 ,男子的马拉松、30 0 0m障碍、跳远、链球等项目 ,女子的 80 0m、15 0 0m、跳远、铅球等项目都略有下降趋势。在此基础上 ,利用 3数据建模预测法 ,给出了奥运会田径主要项目的预测模型和第 2 8届奥运会预测成绩     

田径投掷技术规律在教学中的运用

田径投掷项目不仅技术性强,且较复杂和难掌握。各项目的技术特点和形式虽不同,但它们的关键技术又有相同点,并有着共同的内在本质规律。寻找和把握它们之间共同的技术规律并在教学中加以合理运用,对提高教学效果有着重要的启发和指导作用。