Effects of swing-weight on swing speed and racket power

Abstract

Measurements are presented of the speed at which six different rods could be swung by four male students. Three of the rods had the same mass but their swing-weight (i.e. moment of inertia) differed by large factors. The other three rods had the same swing-weight but different masses. Our primary objective was to quantify the effects of mass and swing-weight on swing speed. The result has a direct bearing on whether baseball, tennis, cricket and golf participants should choose a heavy or light implement to impart maximum speed to a ball. When swinging with maximum effort, swing speed (V) was found to decrease as swing-weight (I _o) increased, according to the relation V?=?C/I _o ⁿ , where C is a different constant for each participant and n?=?0.27 when I _o >?0.03 kg?·?m². Remarkably similar results were obtained previously with softball bats (where n?=?0.25) and golf clubs (where n?=?0.26). Swing speed remained approximately constant as swing mass increased (when keeping swing-weight fixed). The implications for racket power are discussed.     

体操运动中双杠悬垂前摆类动作技术的分类

根据文献资料,且结合当今体操比赛的实际,对双杠悬垂前摆类动作技术进行了分类,即前摆制动类、前摆腾空类,前摆转体类。在此基础上,对每一类动作技术的特点及发展趋势,进行了论述。     

我国高尔夫职业选手张连伟短推技术的运动学分析

运用APAS艾利尔运动技术分析软件及DLT生物力学三维录像分析方法,对我国高尔夫职业选手张连伟短推技术进行了分析。研究表明:除有关力学条件之外,球杆还应在运动区内按一定时间移动,各区的运动距离应按一定的比率随短推击球的距离移动。     

高尔夫运动产业化社会发展的动因与趋势

在现代社会发展的影响下，高尔夫运动迅速发展成为一种新兴的和高附加值的社会产业。论述了现代高尔夫运动产业化社会发展的基本动因和发展趋势：市场发展结构更趋合理，经济发展的包容性和互动性更加强劲；优化企业服务质量、完善企业服务功能、实惠透明的服务消费价格；企业管理水平向着专业化和科学化方向发展。     

从涅莫夫雅典奥运会体操单杠飞行动作看振浪技术与肌肉用力感觉方法的训练

单杠正握向后大摆振浪动作是发展单杠高难度下法型、大回环型、空翻再握型和空翻越杠再握型的基础.文章对4种类型振浪技术动作中出现的9种肌肉用力感觉的方法,通过参考文献,经验的传授,进行归纳与总结,得出不同类型振浪技术动作中的各种肌肉用力感觉的方法,并对它们的相同之处与不同之处的重点部位找出有效的训练手段.     

An overview of cricket ball swing

The aerodynamic properties of a cricket ball have intrigued cricket players and spectators for years, arguably since the advent of the game itself. The main interest is in the fact that the ball can follow a curved flight path that may not always be under the control of the bowler. The basic aerodynamic principles responsible for the nonlinear flight or ‘swing’ of a cricket ball were identified decades ago and many papers have been published on the subject. Over the last 25 years or so, several empirical investigations have also been conducted on cricket ball swing, which revealed the amount of attainable swing and identified the parameters that affect it. Those findings are reviewed here with emphasis on phenomena such as late swing and the effects of humidity on swing. The relatively new concept of ‘reverse swing’, how it can be achieved in practice, and the role in it of ‘ball tampering’, are also discussed in detail. In particular, the ability of some bowlers to effectively swing an old ball in the conventional, reverse and the newly termed ‘contrast’ swing mode is addressed. A discussion of the ‘white” cricket ball used in the 1999 and 2003 World Cup tournaments, which supposedly possesses different swing properties compared to a conventional red ball, is also included. This is a current overview of cricket ball swing rather than a detailed review of all research work performed on the topic. The emphasis is on presenting scientific explanations for the various aerodynamic phenomena that affect cricket ball swing on a cricket ground.     

高尔夫球童职业能力指标体系构建研究

高尔夫球童的职业能力制约着俱乐部的服务水平和高尔夫球产业的持续发展,因此招募与培训球童成为各高尔夫球俱乐部发展的重要环节。以秦皇岛市黄金海岸海滨高尔夫球俱乐部为例,运用文献资料法、访谈法和层次分析法,构建起涵盖11项指标的高尔夫球童职业能力指标体系,其中身体素质、安全保障、观察力和熟悉高尔夫球场是基础能力。旨在为球童的招募与培训工作提供依据,推动球童的职业化发展和产业服务水平提升。     

普通高校高尔夫球体育课教学应把握的四个环节

结合现阶段普通高校高尔夫球公共体育课教学的实际情况,提出了从课程总体定位、课堂内容设置、教学模式探索、师资力量培养及通用教材建设等相关环节进行有针对性地改进和完善的思路和方法。     

网球底线反手切削球技术划分及运动学参数比较分析

采用文献法、录像解析法、访谈法等研究方法,以国家女子网球运动员为研究对象,对底线反手切削球关键技术动作进行三维录像和解析.结果表明:不同高度的来球其引拍和挥拍的动作不同,依据其动作特点可分为切削、平削和压削三种技术.分析发现:三种切削球技术动作在转体引拍和挥拍切削时的肩髋转动角、拍面角、身体倾斜角有显著差异;三种技术的挥拍动作均是由转体、拍臂依次加速的鞭打动作.以此研究揭示底线反手切削球技术的本质特征,为进一步提高网球教学和训练提供理论参考.     

高尔夫球回归奥运会的文化学思考

检视高尔夫球在奥运会历史中的百年沉浮,分析奥林匹克文化圈对现代高尔夫球的影响,阐述了奥林匹克文化彰显对高尔夫球运动的需求。揭示奥林匹克文化全球体育话语权提升的宏观背景下,高尔夫球融入奥运会的主动性和必然性。研究认为,高尔夫球回归奥运会,既是历史的必然,也是现实的要求,它为高尔夫球的发展注入了奥林匹克运动文化价值和精神理念元素,更为奥林匹克运动的改革与发展提供了文化意义上的解读。