Ball launch conditions for skilled golfers using drivers of different lengths in an indoor testing facility

Abstract

The displacement of the golf ball struck by a driving club is affected by several player characteristics and equipment parameters and their interrelationships. Some modelling and simulation studies have shown a relationship between shaft length and clubhead speed, supported by a few experimental studies. The aim of the present study was to examine the relationship between driver length and ball launch conditions in an indoor test facility using a ball launch monitor. Nine males considered to be skilled golfers participated in the study. Four driving clubs of total length 117, 119, 124, and 132 cm were assembled from commercially available components and were used to strike golf shots while initial ball velocity, backspin rate, and launch angles were measured. Statistical analysis identified a significant difference in initial launch speed due to club length, a significant difference between participants, but no difference between the trials for a given golfer. A positive trend was noted between backspin and launch angle for all four clubs, and significant inverse associations between initial launch speed and backspin rate and launch angle. However, the combined launch conditions associated with increasing length were not considered optimal, with uncontrolled swingweight and moment of inertia effects considered to be limiting factors.     

多球训练法在初级网球训练中的应用研究

运用文献资料、实验和数理统计等研究方法,对少年儿童网球初级阶段多球训练法中"一球一击"和"单球"两种不同的训练手段进行了研究。     

浅析柔力球太极类套路发展

太极柔力球作为一项新兴的民间体育活动,在其发明至今的短短十几年里,它以自己深厚的文化内涵以及鲜明的民族特色,逐渐成为我国颇具群众基础的健身运动项目之一。其中太极类套路以其刚柔并济的风格深受广大球友的喜爱。为了推动太极类套路的进一步普及和推广,促进柔力球项目的进一步发展,文章运用文献资料法、专家访谈法和问卷调查法对柔力球太极类套路的发展状况进行了调查。研究结果表明:太极类套路具有更加鲜明的观赏价值、健身价值和文化价值;其深受广大球友的喜爱但在竞赛中鲜有人问津;在太极类套路的发展中存在有难度水平较高,缺乏年轻专业的教练员以及规范的管理机构的支持等弱势。建议采用合适的教学方法,并加大师资力量的储备,争取组织管理机构更多的支持,加大宣传推广的力度,并进一步开发自身的价值,促进太极类套路的推广的普及,推动柔力球项目向产业化方向发展。     

我校大学生参与球类锻炼情况的调查分析

通过问卷调查法对我校大学生球类项目参与情况进行了调查分析。结果表明:本校大学生的球类项目运动兴趣是十分浓厚的,学生参与运动的动机较为明确,是对球类项目运动的兴趣爱好和提高身体素质;参与球类运动的频度和持续时间基本合理;大部分学生都喜欢球类运动,有待于更广泛地在高校普及各种球类运动性项目。通过本研究旨在为更好的促进高校球类运动项目的发展提供参考。     

“打击-轮换”训练法在网球底线击球训练中的实验研究

运用“打击-轮换”声控训练法,对上海市杨浦区少体校网球运动员进行为期1年的训练后发现,运动员的心率、最大摄氧量、公斤体质量最大摄氧量、呼吸商、代谢当量、能量代谢方式均发生明显变化,测试冲关数、测试底线击球数、底线击球成功率都有了较大的提高.研究表明“打击-轮换”声控训练法,能有效提高专业网球运动员的心肺功能和底线有氧击球运动能力,并且运动员的有氧运动能力与运动水平成正比,有氧运动能力强时底线跑动击球能力就强,底线击球成功率也高.     

A review on the basketball jump shot

The ability to shoot an effective jump shot in the sport of basketball is critical to a player's success. In an attempt to better understand the aspects related to expert performance, researchers have investigated successful free throws and jump shots of various basketball players and identified movement variables that contribute to their success. The purpose of this study was to complete a systematic review of the scientific literature on the basketball free throw and jump shot for the purpose of revealing the critical components of shooting that coaches, teachers, and players should focus on when teaching, learning, practising, and performing a jump shot. The results of this review are presented in three sections: (a) variables that affect ball trajectory, (b) phases of the jump shot, and (c) additional variables that influence shooting.     

一种单列角接触球轴承的设计

角接触球轴承的设计涉及许多结构参数。着重介绍了角接触球轴承的钢球、内外套圈等零件主要参数的确定。基于用户要求,运用ZYB28-98角接触轴承的设计方法,首先确定了所需要的钢球直径和钢球数,并计算了其径向额定负荷。接着详细介绍了内外沟曲率半径、内外圈沟径、内外圈挡边直径等主要参数的计算过程。     

太极柔力球项目在高校开展的现状及推广策略

采用文献资料法、问卷调查法、数理统计法,对连云港市高校开展太极柔力球项目的现状进行调查与分析,并提出推广策略,试图能为太极柔力球项目在高校中的进一步推广提供参考。     

襄阳市柔力球运动发展现状及对策

运用专家访谈法、问卷调查法等科研方法,对襄阳市柔力球运动发展现状进行调查及分析,发现柔力球运动在襄阳市的发展较好,运动师资、裁判储备较为丰富,锻炼群体主要是退休中老年女性,锻炼方式主要以柔力球套路为主,在襄阳市学校体育领域处于起步阶段,发展总体前景乐观.提出健全柔力球协会组织,加强教练员、裁判员的业务学习,进校园活动要继续坚持,加强与本市高校合作及充分利用媒体手段对柔力球运动进行宣传等对策.     

基于小型缸体的钢珠自动对中机构研究

小型缸体是汽车产业中最关键的部件。小型缸体由于国内铸造技术偏低,导致缸孔偏心、对中结构误差大、钢珠受力过大等缺点。针对缸体孔偏心的小型缸体定位夹紧工装的国内现状,开发出一套适用小型缸体的钢珠对中机构,进行了受力分析。结果表明该对中机构具有在环境恶劣,湿式或干式加工等应用场合,定位准确可靠,使用寿命长的优点。在国内目前没有解决小型缸体铸造变形导致缸孔偏心的情况下,很值得大力推广,有很高的应用价值。