乒乓球运动员膝关节损伤机制研究——对3种常用步法的膝关节负荷特征分析

目的:了解不同性别乒乓球运动员完成并步、跳步、跨步3种常用步法时膝关节的负荷特征,并探析乒乓球运动员膝关节的损伤机制。方法:对乒乓球男、女各10名运动员完成3种常用步法动作时的下肢运动学、动力学数据进行采集和处理,并运用方差分析法比较不同性别、不同技术之间的差异。结果:受试者在完成3种步法过程中,膝关节屈角大致范围在20°~60°。当地面反作用力最大时,女运动员比男运动员表现出更小的外展角(P<0.05),跳步比并步和跨步表现出更小的外展角(P<0.05);在三维受力方面,膝关节受到垂直方向上的力最大,水平向后和向左的力次之,未表现出显著的性别差异和技术差异;在三维力矩方面,膝关节受到的伸膝力矩较大,也未表现出显著的性别差异和技术差异。结论:膝关节屈曲状态下,较大的地面反作用力和膝关节外展角易导致乒乓球运动员前交叉韧带损伤,女运动员的损伤风险小于男运动员,跳步的损伤风险小于并步和跨步;水平向后和向左的力易造成乒乓球运动员软骨和半月板损伤;过大的伸膝力矩易导致乒乓球运动员髌腱末端病和髌骨软化。     

三维影相的新算法——修正的直接线性变换

通过引入摄影机镜头的内、外方位元素的约束条件,导出了一种修正的DLT(MDLT)方法。该方法用于影片和录相的实测,得到一些有意义的结果。当测量的标定控制点点数较少(6～8个),且这些点的位置在空间和成像面分布不均匀时,用MDLT计算的结果比DLT的结果要好,误差可降低80％以上。     

TFPS 教学用运动技术影片分析系统的教学应用

TFPS 教学用运动技术影片分析系统(Teaching's Film Processing System)的应用,彻底改变了以往影片分析方法教学的一般性介绍的状况,以实验部分为核心,采用新的教学方法,借助新的教学仪器,使理论与实践相结合,大大加深了学生对这一方法的理论知识的理解和掌握,同时使学生亲自动手实验,掌握实际实验技能,大大提高了进行运动技术分析的研究能力,填补了这一教学领域的空白,使这一领域的教学水平和教学质量达到了国内领先水平和国际先进水平。     

Baseball

The purpose of this study was to quantify and compare kinematic, temporal, and kinetic characteristics of American and Korean professional pitchers in order to investigate differences in pitching mechanics, performance, and injury risks among two different cultures and populations of baseball pitchers. Eleven American and eight Korean healthy professional baseball pitchers threw multiple fastball pitches off an indoor throwing mound positioned at regulation distance from home plate. A Motion Analysis three‐dimensional automatic digitizing system was used to collect 200 Hz video data from four electronically synchronized cameras. Twenty kinematic, six temporal, and 11 kinetic variables were analyzed at lead foot contact, during the arm cocking and arm acceleration phases, at ball release, and during the arm deceleration phase. A radar gun was used to quantify ball velocity. At lead foot contact, the American pitchers had significantly greater horizontal abduction of the throwing shoulder, while Korean pitchers exhibited significantly greater abduction and external rotation of the throwing shoulder. During arm cocking, the American pitchers displayed significantly greater maximum shoulder external rotation and maximum pelvis angular velocity. At the instant of ball release, the American pitchers had significantly greater forward trunk tilt and ball velocity and significantly less knee flexion, which help explain why the American pitchers had 10% greater ball velocity compared to the Korean pitchers. The American pitchers had significantly greater maximum shoulder internal rotation torque and maximum elbow varus torque during arm cocking, significantly greater elbow flexion torque during arm acceleration, and significantly greater shoulder and elbow proximal forces during arm deceleration. While greater shoulder and elbow forces and torques generated in the American pitchers helped generate greater ball velocity for the American group, these greater kinetics may predispose this group to a higher risk of shoulder and elbow injuries.     

骨伤学科与力学学科的学科渗透与融合

分析了骨伤学科与力学学科分化与综合的发展历史。通过生物力学、动力学、振动力学等在骨伤学科中的应用,说明骨伤学科与力学的渗透与融合,也说明分化是学科发展的必要条件,综合是学科发展的必然趋势。     

略论运动生物力学的研究方法与测量技术

文章认为:1,仅依靠牛顿分析力学的研究方法,运动生物力学只能停留在“研究人体机械运动规律”的水平,“走出系统”的研究方法适合于对活体系统的生物力学研究;2,“理论模型”需数据支持才具有应用价值,“数据模型”需相应的数学化才具有理论意义;3,活体运动过程的测量应建立参数采集与测量的标准化和参数分析与评价的专家系统;4,应界定常规参数和敏感参数,并区别参数间的平行关系和因果关系,测量精度的提高主要应依靠测量参数数字化过程的分析方法的进步。     

体育教学中几个基本生物力学问题的认识及其解

将体育教学和运动训练中各种运动动作归纳为几个基本的生物力学问题,即平衡问题、抛体问题、碰撞问题、鞭打问题、流体问题。这将有利于学生认识和把握动作的本质规律．并提高学习和训练效果。     

山东省64公斤级男子拳击运动员直拳技术动作的运动生物力学分析

利用高速摄像与测力台(Kistler)同步测试的方法,对山东省5名64公斤级男子拳击运动员直拳技术动作进行测试,发现山东省运动员直拳技术基本符合理论要求;拳速比世界优秀拳击运动员小;躲闪速度不够快;出前直拳时髋转动幅度较小;出后直拳时蹬地不充分.     

女子链球运动员冬季准备期前后的等速测试

通过对两名高水平女子链球运动员双侧的髋关节和膝关节进行等速测试,探究运动员髋关节和膝关节周围肌群的生物力学特性,为运动训练和运动康复等提供理论依据。利用等速肌力测试系统对两名运动员的髋关节和膝关节屈伸肌群以及髋关节的旋内旋外肌群进行等速测试。结果发现:两名运动员双侧髋关节和膝关节屈伸肌群以及髋关节的旋内旋外肌群的峰力矩随测试速度的增加呈递减趋势,髋膝关节峰力矩屈伸比和髋关节旋内旋外比随既定测试速度的增加呈递增趋势;同一测试速度下,伸肌肌群的峰力矩大于屈肌肌群,髋关节旋外肌群的峰力矩大于旋内肌群。     

Theoretical Analysis of Aggressive Golf Putts

Abstract

The present study examined the relationship between students' perceptions of the motivational climate and beliefs about the causes of success, preference for challenging tasks, and satisfaction in physical education. Responses of 50 female and 46 male students (M age = 12.08 years; SD = .72) showed that perceptions of a mastery-oriented motivational climate were related to the belief that motivation or effort caused success and satisfaction. In contrast, perceptions of a performance climate were related to the belief that deception caused success and related negatively to the students' preference for challenging tasks. Results of hierarchical regression analyses revealed that perceptions of the motivational climate explained a significant amount of unique variance in the students' responses after controlling for dispositional goal orientations. The results suggest that the teacher can influence the salience of a mastery-oriented climate and, in so doing, optimize a child's motivation in physical education.