Vision testing method for diameter,roundness and hardness of table tennis ball

Under the premise of fully respecting current national standard of table tennis ball,this paper presents an integrated and effective method for testing diameter,roundness and hardness of table tennis ball based on vision measurement. Firstly,camera calibration is performed by 40 mm gauge block to capture the images of table tennis ball in static and pressed state in an appropriate lighting condition. Then image binarization and extraction of image contour are carried out. The least square method is used to fit its center. Finally,the diameter,roundness and hardness are calculated. The measurement data are analyzed by using the method presented in this paper for table tennis ball with known parameter data and with unknown parameter data. Experimental results show that this method can improve measurement accuracy and provide a technical basis for the online testing and integration measurement of table tennis ball.

Correlation analysis of national elite Chinese male table tennis players’ shoulder proprioception and muscle strength

BACKGROUND Shoulder is the most injured part in table tennis players,and it takes multiple roles in transmitting power and striking the center of the ball during the stroke.Proprioception is strongly correlated with high level of athletic performance.It is customary to assume that there is a correlation between proprioception and muscle strength and therefore proprioceptive assessment and rehabilitation is often neglected.AIM To investigate the correlation between isokinetic muscle strength and proprioception in the internal and external rotation muscle groups of elite Chinese male table tennis players,to provide reference for physical training and rehabilitation of elite table tennis players.METHODS A total of 19 national elite table tennis players from the Chinese National Table Tennis Team were recruited in this research.All of them had more than 10 years training experience and had participated major competitions such as the National Games and World Youth Championships.IsoMed 2000 was used to test the peak torque of internal and external rotation isokinetic concentric contraction of the athletes'bilateral shoulder joints at low speed(60°/s)and high speed(180°/s)respectively;IsoMed 2000 was used to conduct the Joint Position Reproduction test to evaluate the athletes'proprioceptive ability capacity at low speed(60°/s)and high speed(180°/s)respectively.If the data satisfied the normal distribution,the correlation between the differences in peak torque s and angles in different directions was analyzed using a Pearson simple linear model;otherwise,Spearman correlation analysis was used.The comparison of proprioceptive ability between the table tennis racket-holding hand and non-racket-holding hands was performed using independent samples t-test if the data satisfied a normal distribution;otherwise,the Mann-Whitney U test was used.RESULTS There was no direct linear correlation between the strength and proprioceptive correlation analysis at slow speed(60°/s)and fast speed(180°/s)in the racket-holding hand;At the slow speed(60°/s)and fast speed(180°/s),there was no correlation between muscle strength and proprioception in the non-racket-holding hand except for the internal rotation variable error(VE)and external rotation relative peak torque,which showed a moderate positive correlation(r=0.477,P<0.05),(r=0.554,P<0.05).The internal rotation’s constant error(CE)and VE were 1.06±3.99 and 2.94±2.16,respectively,for the racket-holding hand,and-3.36±2.39 and 1.22±0.93,respectively,for the non-racket-holding hand;the internal rotation’s CE,VE of the racket-holding hand was lower than that of the non-racket-holding hand,and there was a highly significant difference(P<0.01).CONCLUSION There was no correlation between muscle strength and proprioceptive function in the internal and external rotation of the racket-holding hand’s shoulder in elite Chinese male table tennis players.These results may be useful for interventions for shoulder injuries and for the inclusion of proprioceptive training in rehabilitation programs.

Longitudinal trajectories of athlete burnout among young table tennis players: A 3-wave study

Purpose:The purposes of this study were to examine the trajectories of athlete burnout across a 2-month period characterized by high physical,psychological,and social demands to explore(1)whether several subgroups of athletes representing distinct burnout trajectories emerged from the analyses and(2)whether athlete burnout symptoms(reduced accomplishment,sport devaluation,and exhaustion)developed in tandem or whether some burnout dimensions predicted downstream changes in other dimensions(causal ordering model).Methods:One hundred and fifty-nine table tennis players in intensive training centers completed a self-reported athlete burnout measure across 3 time points within a 2-month period characterized by high demands.Data were analyzed through latent class growth analysis.Results:Results of latent class growth analysis showed 3 distinct trajectories for each athlete burnout dimension,indicating not only linear or quadratic change but also stability in longitudinal athlete burnout perceptions.Results also suggested that the 3 dimensions of athlete burnout did not develop in tandem.Rather,the likelihood of belonging to particular emerging trajectories of sport devaluation and physical/emotional exhaustion was significantly influenced by the athletes’perception of reduced accomplishment assessed at Time 1.Thus,reduced accomplishment predicted downstream changes in the 2 other athlete burnout dimensions.Conclusion:As a whole,these results highlighted that the multinomial heterogeneity in longitudinal athlete burnout symptoms needs to be accounted for in future research.

Testing method for veer of table tennis ball

Under the premise of fully respecting Technical Leaflet T3developed by the International Table Tennis Federation(I T T F),this paper proposes an effective method for testing the veer degree of the table tennis ball based on airflow suspension and machine vision.By sequentially capturing the images of the ball in the stable state of spinning and suspension,a set of fitting circle centres from different circular sections can be obtained by circle fitting through the least square method.The minimum circumscribed circle(MCC)diameter of these centres is served as a basic parameter to evaluate the veer degree of the ball.Experimental results show that this diameter can effectively reflect the veer degree of the ball.The method proposed in this papercan provide a technical basis for the veer online testing of the table tennis ball.

Analysis of the Duration and Rest Time of Wheel Chair Para Table Tennis at the Rio 2016 Paralympic Games

The purpose of this study was to analyse and compare the match characteristics of wheelchair PTT （Para table tennis） classes that played in the team tournament at the Rio 2016 Paralympic. Eight PTT matches of each selected class （1, 2, 4 and 5） were analysed.The variables analysed were DR （duration of rally） and RT （rest time）. In observing the characteristics of the matches in Classes 1, 2, 4 and 5, the DR corresponded to 3.4 ± 1.2, 4.2 ± 1.5, 4.5 ± 1.6 and 5.2 ± 1.2 seconds, and RT to 13.8 ± 3.5, 14 ± 3.5, 13.3 ± 3.1 and 12.3± 3.3 seconds. In Classes 1 and 2, significant differences in DR were found, but none in RT （p 〉 0.05）. In the DR and RT of classes 4 and 5 there were significant differences （p 〈 0.05）. The results indicated that the DR in Classes 1 and 2 were different because of sitting balance due to severe reduction of function in Class 1 playing arm, interfering in the rally and rest. In Classes 4 and 5 the differences in DR and RT were caused by little sitting balance in Class 4. These characteristics should be used by coaches to check the disadvantages that Class 1 presents against Class 2, and the physical limitations of Class 4 that can directly influence DR in the team tournament against athletes with normal trunk muscle function （Class 5）. Planned training prescriptions between classes would aim at achieving better sport performance in training and team tournaments.

The Impact of Developing Coordination Abilities on the Skill Abilities for Table Tennis Iuniors

The coordination abilities are closely related to the development of technical motor skills, where the player cannot master the technical skills in the special activity, in case lack of special coordination abilities for this activity. Many of table tennis experts agree on that the special coordination abilities for table tennis include each of： （1） the motor adaptation and adjustment ability; （2） the ability to differentiate; （3） reaction speed ability; （4） orientation ability; （5） balance ability; （6） coupling ability; and （7） the ability to sense the rhythm. The aim of this study is to design a training program to develop the special coordination abilities of table tennis and identify the impact of this program on the general skill ability for table tennis juniors. The researcher used the experimental method in two groups： One group is experimental group and another is the control group. The most important result of this study was the training program led to the improvement of the special coordination abilities of table tennis for the experimental group, which led to higher levels of the general skill ability in table tennis for the experimental group more than the control group.

高校乒乓球教练员执教能力提升对策

教练员的执教能力直接关系到运动员的训练效果以及在比赛中的表现,也是衡量教练是否合格的关键要素。在高校乒乓球训练中,教练员不可或缺。为了提高教练员的执教能力,促进高校高水平运动队的运动训练更加科学,使队员能够在比赛中取得优异成绩,就需要采取有效的措施确保教练员的执教能力得到提升。

乒乓球战术五项指标统计法的建构与应用研究

为更好地提升乒乓球技战术定量分析效果,构建了乒乓球战术五项指标统计法,并与传统三段法的特点和具体运用进行了对比分析。结果表明:五项指标法破解了战术归“段”时固定得失分板数的规约,最大限度确保战术归“段”准确;厘清了由“抢”入“持”的衔接过程,更明确、深入地揭示由“抢”入“持”的衔接特点;战术指标的内涵更精准、贴切,更充分、准确地揭示运动员的技战术运用特点和世界乒乓球技战术发展的最新特点。

乒乓球运动员心理素质培养的策略与方法

随着竞技体育水平的不断提高,心理素质已成为决定运动员竞技表现的关键因素之一。通过理论与实证研究,分析了心理训练在提高运动员适应能力、竞技状态和压力管理方面的作用,并提出了具体的心理训练策略。这些策略不仅有助于优化训练效果,还能显著提升比赛中的心理调控能力。通过案例研究和数据分析,旨在为乒乓球教练员和运动员提供一套科学、实用的心理训练指导方案。

“课程思政”在高职院校乒乓球选项课教学中的融入路径研究

将乒乓球运动所蕴含的思政元素融入到选项课教学中,有利于实现“课程思政”的协同育人目标,落实高校德育工作。本文运用文献法、归纳法阐述了“课程思政”融入乒乓球选项课的重要意义,探讨了高职乒乓球选项课教学融入“课程思政”的现状和问题,进而提出了“课程思政”融入乒乓球选项课的实践路径,包括明确思政定位的教学目标、优化“课程思政”教学方法、完善考核评价体系、提高教师思政教学能力。

DWT算法在乒乓球动作识别分析中的应用

针对传统乒乓球动作识别未考虑动作的时序性和动态特性的问题,研究在二维DWT算法的基础上引入奇异值分解,设计出一种改进DWT算法,以获得乒乓球动作的局部特征,从而提升其识别准确率。实验结果显示:在识别准确率计算中,改进DWT算法的平均识别准确率为97.8%,优于其他算法,表明其识别精度较高;在识别时间计算中,改进DWT算法的识别时间与其他算法相比,均下降了50%左右,表明其识别效率较高。以上结果证明了改进DWT算法的优越性能,为乒乓球的动作识别提供了有效的技术支持。

不同缓冲性能乒乓球鞋对人体下肢落地冲击力的影响研究

为分析不同缓冲性能的乒乓球鞋在剧烈运动落地时对人体下肢冲击力的影响,选择20位乒乓球运动员为研究对象,通过比较研究对象在疲劳干预后穿着不同缓冲性能的乒乓球鞋从50cm高处落地时的下肢冲击力、负载率等参数,从生物力学视角下对穿着乒乓球鞋从高处落地时人体下肢的冲击力影响进行分析。结果表明:良好的缓冲能够明显增强人体髋关节、膝关节或是踝关节落地角度变化量,显著增强人体下肢稳定性,但不能显著影响人体落地时踝关节处神经-肌肉的控制情况。

乒乓球和羽毛球优秀男子运动员身体形态及机能特征的比较研究

运用文献资料、专家调查、测量和数理统计等方法,对19名男子优秀羽毛球运动员、12名男子优秀乒乓球运动员的肢体长度、结实度、身体素质、有氧、无氧能力等5项一级指标开展研究,分析其身高、体重骨密度、克托莱指数等33项二级指标数据。结果表明:二者在肢体长度、肌肉含量、骨密度、上肢握力、最大摄氧量、WinGate10s功率等多项指标上具有显著性差异。该结果可对两个项目的选材和科学训练提供参考。

基于BP神经网络的乒乓球优秀女子单打比赛结果预测模型构建及仿真应用

为构建优秀女子运动员技战术表现与比赛获胜的理论模型,合理安排技战术训练及比赛策略提供参考借鉴。运用录像观察法、数理统计法及BP神经网络构建乒乓球优秀女子单打比赛结果预测模型。在此基础上,利用预测模型仿真分析新型塑料球时代优秀女子乒乓球运动员在不同水平技战术组合下的比赛获胜模式。本文构建的预测模型R为0.978,R~2为0.956,平均绝对误差为0.0085,模型精度达到98.4%;仿真分析1 024种技战术段组合结果可知,568种组合的预测结果为获胜,456种组合的预测结果为失败。结论:基于BP神经网络构建的乒乓球优秀女子单打比赛结果预测模型拟合效果佳,个案实证预测效果较好,具有较高的预测性能;新型塑料球时代优秀女子运动员在单打比赛中,各技战术段之间的补偿效应因技战术段和等级而有所不同,评估总分17分为女子单打比赛胜负的分界点,不同水平技战术段组合的比赛评估总分大于17分即可取得比赛胜利,低于17分则会落败。

基于加速度计阵列的乒乓球智能判分系统

乒乓球比赛在国际比赛、体育教学、休闲健身等领域备受关注。针对乒乓球比赛中裁判员主观局限性导致的判分人为误差、球员训练效率与实时性差等问题,提出了一种基于MEMS加速度计阵列的乒乓球智能判分系统。为了精准检测桌面落球位置,采用ADXL335加速度传感器模块测量球-桌碰撞引起的桌面振动信息。通过优化加速度传感器阵列节点,开发多信号协同感知算法,实现球桌表面落球点的精确定位。此外,结合落球点坐标信息,开发了基于国际乒乓球比赛规则的智能判分和比分实时显示上位机模块。实验结果表明:所开发的乒乓球判分系统具有智能裁判、比分实时显示、落球点精准定位、坐标信息存储等功能,为乒乓球比赛精准智能裁判和球员数字化训练提供了一种实用的设计方案。

第57届世界乒乓球锦标赛女单决赛孙颖莎技战术分析

该文主要运用文献综述法、录像观察法,对孙颖莎在实战中的技战术应用情况进行统计。采用三段技术统计法,对孙颖莎在第57届世界乒乓球锦标赛女单决赛中的发抢阶段、接抢阶段与相持阶段3个阶段的技战术进行分析。通过研究结果可以看出,孙颖莎的发球抢攻技术是重要的得分手段,在接抢段表现较为优秀,能够对来球进行有效的控制,回球质量高,相持阶段应加强正手来球的保护意识。该文为孙颖莎技战术水平的提高提出相应的建议,为女子运动员后备人才的培养及技战术打法训练提供借鉴。