如何打好和对付旋转球

由于现代乒乓球运动的各种主要打法打出的球都带有旋转,所以进一步研究如何打好和如何对付旋转球,对提高技术将是有益的。一、如何打好旋转球(一)加强旋转:一般来说,加转球威力较大。同时只有打好加转球,才能与不转球有较大的悬殊,以增加“真假旋转球”或“转与不     

旋转球对正碰篮板球命中率影响的生物力学分析

本文根据运动生物力学基本原理和方法,分析、探讨了前旋球、后旋球、左旋球及右旋球等4种旋转球对正碰篮板球命中率的影响。     

多球训练在少儿乒乓球训练中的运用

针对目前多球训练在少儿乒乓球训练中的研究现状，运用文献综述法和实地考察法，对乒乓球多球训练法的产生及其特点、少儿生理特点和少儿乒乓球多球训练的特点进行了分析，研究了多球训练在少儿乒乓球训练中动作技能形成的3个阶段的特点，并结合少儿的生理特点选用不同的多球训练方法，在训练内容、训练方式、训练强度等方面进行科学合理的安排，为多球训练法在今后少儿乒乓球训练中的实际运用提供一定的理论依据。     

运动记忆规律运用于高校乒乓球正手攻球教学研究

基于乒乓球正手攻球的技能特点,分析乒乓球正手攻球的运动记忆规律,厘清正手攻球的前摄干扰与正迁移,理解正手攻球教学的热身损耗原理,建立合理的正手攻球长时记忆动力定型。在现实教学中,依据正手攻球的运动记忆特点与遗忘进程,认清大学生学习动机、运动基础与性别的差异,进行乒乓球正手攻球运动记忆的教学策略探讨。     

乒乓球旋转的实验研究——国家乒乓球队主要技术转速常量分析

旋转是比赛中制胜的因素之一。对旋转球的定性研究已积累了许多知识和经验,但由于测试手段的限制,对旋转球的定量研究一直是个空白。本文运用通过部级鉴定的PD-1型乒乓球动态测转仪,对不同训练水平、不同打法、不同球拍性能的二组24名运动员的发球、搓球、孤圈球(高吊孤圈、前冲孤圈)、削球等主要技术的旋转常量作了报道,初步探讨了训练水平、球拍性能、技术动作与旋转强度(转数/秒)之间的关系,在国内外乒坛首次公布了定量研究结果。     

乒乓球的球性球感练习

乒乓球运动中的动作技能形成一般可分为四个阶段:熟悉球性球感阶段、粗略地学习掌握技术动作阶段、改进与提高技术动作阶段、巩固和运用自如阶段。由于乒乓球运动不同于其它体育项目,它有其熟悉球性获得球感的特殊过程,因此对少年     

浅谈乒乓球运动员对来球的判断

通过对乒乓球运动中的判断能力的分析与探讨，阐明了判断在乒乓球整个技术过程中的关键作用，并指出在理论上去理解它，实践中去掌握它，是提高乒乓球技术水平至关重要的因素。     

乒乓球“飘球”技术的可行性理论分析

从乒乓球运动的发展现状、运动生物力学原理、动力相似性原理出发,从理论上提出了乒乓球“飘球”技术,并对其可行性进行了较全面的分析阐述,旨在为乒乓球技术动作创新提供理论依据。     

利用伯努力方程式解释排球发球中旋转球的几种现象

发球是排球比赛中一项重要的进攻技术。它是一号位队员在发球区域内自己抛球后，用一只手将球直接击入对区的一种击球方法。发球的种类很多，一般可分为旋转球和飘球两大类，旋转球按发球的方式大体可分为四类，即左旋球、右旋球、上旋球(前旋球)、下旋球(后旋球)。现在我们来研究一下旋转球的几种现象。     

飘球形成的主要原因是什么——与张永良、许浒两同志商榷

正确分析飘球原理,对于指导发球技术有着重要的意义。张永良同志的《飘球原理的分析》(体育科研77年第11期)和许浒同志的《对旋转球和不旋转球的原理的分析》(体育科技78年第11期),对排球运动的发展起着积极的作用,阅读后很有启发。但感到有些问题有必要提出来与两位同志商榷。     

乒乓球的动态特性——旋转与速度相对原理

乒乓球的旋转与速度存在着相对关系,是乒乓球技术中的普遍规律。在论证中提出了相对速度与球心速度之比作为特征准数,将点的运动轨迹分为三类,分别为“螺旋线”“波纹线”和“旋轮线”。从而将复杂的乒乓球技术划分为“旋转型”“速度型”和“综合型”三种基本类型。运动员击球的点在第二轨迹不同的位置上合成速度不相等。因此,运动员在第二轨迹的不同阶段击球手感旋转不相同,而且该点的合成速度矢量决守乒乓球技术的打法特征。根据高吊弧圈球与前冲弧圈球的特征准数不同,说明了运动员对这两种球型接球手感旋转不同的原因。     

球的后旋对中远距离投篮作用的探讨

章运用力学原理，针对球的后旋在中远距离投篮中出现的各种情况进行分析，旨在阐述球的后旋在中远距离投篮中的重要性，以引起有关人士的重视，为在投篮教学和训练中注重球的后旋问题提供理论依据。     

A mathematical analysis of the motion of an in-flight soccer ball

In this paper, an analytical and numerical study of the three-dimensional equations describing the motion through the air of a spinning ball is presented. The initial analysis involves constant drag coefficients, but is later extended to involve drag varying with the spin ratio. Excellent agreement is demonstrated between numerical, analytical and experimental results. The analytical solution shows explicitly how the ball’s motion depends on parameters such as ball roughness, velocity and atmospheric conditions. The importance of applying three-dimensional models, rather than two-dimensional approximations, is demonstrated.     

The role of upper torso and pelvis rotation in driving performance during the golf swing

While the role of the upper torso and pelvis in driving performance is anecdotally appreciated by golf instructors, their actual biomechanical role is unclear. The aims of this study were to describe upper torso and pelvis rotation and velocity during the golf swing and determine their role in ball velocity. One hundred recreational golfers underwent a biomechanical golf swing analysis using their own driver. Upper torso and pelvic rotation and velocity, and torso-pelvic separation and velocity, were measured for each swing. Ball velocity was assessed with a golf launch monitor. Group differences (groups based on ball velocity) and moderate relationships (r > or = 0.50; P < 0.001) were observed between an increase in ball velocity and the following variables: increased torso-pelvic separation at the top of the swing, maximum torso-pelvic separation, maximum upper torso rotation velocity, upper torso rotational velocity at lead arm parallel and last 40 ms before impact, maximum torso-pelvic separation velocity and torso-pelvic separation velocity at both lead arm parallel and at the last 40 ms before impact. Torso-pelvic separation contributes to greater upper torso rotation velocity and torso-pelvic separation velocity during the downswing, ultimately contributing to greater ball velocity. Golf instructors can consider increasing ball velocity by maximizing separation between the upper torso and pelvis at the top of and initiation of the downswing.     

Flight dynamics of the screw kick in rugby

This paper describes the aerodynamic forces and the flight trajectory for the screw (spiral) kick in rugby. The screw kick is defined as that which causes the ball to spin on its longitudinal axis. The aerodynamic forces acting on a rugby ball spinning on its longitudinal axis were measured in a wind tunnel using a six-component strut type balance. It was found that the drag, the lift and the pitching moment depend on the angle of attack, while the side force (Magnus force) depends on both the spin rate and the angle of attack in the range where the wind speed lies between 15 and 30 m s^-1 and the spin rate is between 1 and 10 revolutions per second. Moreover, the flight trajectory was obtained by integrating the full nonlinear six degrees of freedom equations of motion on the basis of aerodynamic data. In a simulation, a ball spinning on its longitudinal axis tended to hook toward or away from the touchline even if the velocity and angular velocity vectors were parallel to the touchline. The direction of the hook depends on the direction of the angular velocity vector. The initial direction of the hook depends on the relationship between the flight path angle and the pitch angle as well as the direction of the angular velocity vector.     

Comparison of a finite element model of a tennis racket to experimental data

Modern tennis rackets are manufactured from composite materials with high stiffness-to-weight ratios. In this paper, a finite element (FE) model was constructed to simulate an impact of a tennis ball on a freely suspended racket. The FE model was in good agreement with experimental data collected in a laboratory. The model showed racket stiffness to have no influence on the rebound characteristics of the ball, when simulating oblique spinning impacts at the geometric stringbed centre. The rebound velocity and topspin of the ball increased with the resultant impact velocity. It is likely that the maximum speed at which a player can swing a racket will increase as the moment of inertia (swingweight) decreases. Therefore, a player has the capacity to hit the ball faster, and with more topspin, when using a racket with a low swingweight.     

Cricket

The laws of bowling in cricket state ‘a ball is fairly delivered in respect of the arm if, once the bowler's arm has reached the level of the shoulder in the delivery swing, the elbow joint is not straightened partially or completely from that point until the ball has left the hand’. Recently two prominent bowlers, under suspicion for transgressing this law, suggested that they are not ‘throwing’ but due to an elbow deformity are forced to bowl with a bent bowling arm. This study examined whether such bowlers can produce an additional contribution to wrist/ball release speed by internal rotation of the upper arm. The kinematics of a bowling arm were calculated using a simple two‐link model (upper arm and forearm). Using reported internal rotation speeds of the upper arm from baseball and waterpolo, and bowling arm kinematics from cricket, the change in wrist speed was calculated as a function of effective arm length, and wrist distance from the internal rotation axis. A significant increase in wrist speed was noted. This suggests that bowlers who can maintain a fixed elbow flexion during delivery can produce distinctly greater wrist/ball speeds by using upper arm internal rotation.     

The effect of a flexed elbow on bowling speed in cricket

The laws of bowling in cricket state 'a ball is fairly delivered in respect of the arm if, once the bowler's arm has reached the level of the shoulder in the delivery swing, the elbow joint is not straightened partially or completely from that point until the ball has left the hand'. Recently two prominent bowlers, under suspicion for transgressing this law, suggested that they are not 'throwing' but due to an elbow deformity are forced to bowl with a bent bowling arm. This study examined whether such bowlers can produce an additional contribution to wrist/ball release speed by internal rotation of the upper arm. The kinematics of a bowling arm were calculated using a simple two-link model (upper arm and forearm). Using reported internal rotation speeds of the upper arm from baseball and waterpolo, and bowling arm kinematics from cricket, the change in wrist speed was calculated as a function of effective arm length, and wrist distance from the internal rotation axis. A significant increase in wrist speed was noted. This suggests that bowlers who can maintain a fixed elbow flexion during delivery can produce distinctly greater wrist/ball speeds by using upper arm internal rotation.     

普通高校乒乓球课学生击球稳定性的影响因素

对普通高校乒乓球课影响学生击球稳定性的众多因素进行多维分析,结果表明:影响学生击球稳定性的主要因子是:动作结构因子、旋转理解因子、发力方式因子、外在客观因子,并据此提出了提高学生击球的稳定性,有利于激发学生学习的积极性,从而提高教学效率。     

乒乓球运动员松平健太的技战术分析

选取松平健太在2013年巴黎世锦赛与XXX的1/4决赛和2013年奥地利公开赛中与中国选手XXX的比赛,从发球、第三拍、接发球、第四拍及相持段对松平健太的技战术表现和特点进行统计与分析,为中国队备战2016年世锦赛提供理论依据。研究结果表明：松平的打法手感细腻,具有一定的战术意识和变化能力,尤其是对于直板打法,具有着独特的见解和体会。松平健太比赛作风硬朗,他在打法上最大的特点是：站位近台,强于速度,敢与对手进行强强对话。他的衔接和相持速度很快,正反手实力均衡,攻与防平衡,没有明显的漏洞,其中反手的加力和变线更为强势。但是松平在快速中,正手主动进攻意识不强,打球节奏过于单一,对于节奏和旋转变化缺乏调节能力,从而显得凶而不稳和快而不转。