Accuracy and Feasibility of Video Analysis for Assessing Hamstring Flexibility and Validity of the Sit-and-Reach Test

The accuracy of video analysis of the passive straight-leg raise test (PSLR) and the validity of the sit-and-reach test (SR) were tested in 60 men and women. Computer software measured static hip-joint flexion accurately. High within-session reliability of the PSLR was demonstrated (R > .97). Test-retest (separate days) reliability for SR was high in men (R = .97) and women R = .98) moderate for PSLR in men (R = .79) and women (R = .89). SR validity (PSLR as criterion) was higher in women (Day 1, r = .69; Day 2, r = .81) than men (Day 1, r = .64; Day 2, r = .66). In conclusion, video analysis is accurate and feasible for assessing static joint angles, PSLR and SR tests are very reliable methods for assessing flexibility, and the SR validity for hamstring flexibility was found to be moderate in women and low in men.     

第11届全运会女子铅球项目前8名运动员关键运动技术参数三维录像分析

本文采用文献研究法、三维录像解析法和统计分析法对第11届全运会女子铅球决赛前八名运动员最好成绩投次进行关键运动技术研究,获取她们的部分关键运动学参数,同时和世界级优秀运动员的相应参数进行比较分析,得出相应的研究结果。本论文的主要研究结论为1.背向滑步转身跳投技术按整体动作结构可分为后摆、滑步、过渡、双支撑和最后出手投掷五个阶段。2本研究再次证明了出手速度与比赛成绩呈高度正相关,相关系数达到0.95。而出手角度和其他运动学参数与成绩呈中低度相关。3.本届全运会中冠军巩立娇6次试投平均成绩为19.60±0.46m;平均出手速度为13.47±0.24m/s,与世界级选手接近;平均出手角度为33.99±1.23°,低于世界级优秀运动员;平均出手高度为2.03±0.03m,距离抵制板的水平距离平均为-0.03±0.08m。4.前3名运动员李玲、李梅菊和巩立娇最好成绩投次质心最大分别为速度为2.84m/s、2.65m/s和2.91m/s,质心最大速度与成绩相关性不大。铅球的出手速度为12.69m/s,13.31m/s和13.84m/s,出手角度为38.5°、35.5°和33.9°,铅球的出手高度为2.09m、1.98m和2.06m。     

Hammer acceleration due to thrower and hammer movement patterns

Ground reaction force and wire tensile force were measured during test throws by three hammer throwers: the Asian record holder, who had a personal best of 83.47 m at the time of the investigation, and two university athletes, with personal bests of 59.95 m and 46.30 m respectively. They were filmed using three high-speed video cameras (250 Hz). The displacements of the hammer head and the athletes' centres of mass were calculated using three-dimensional analysis procedures. The Asian record holder's centre of mass and the hammer head on the final two turns exhibited approximate conjunctions of the hammer high point and the thrower's low point and vice versa about the hammer's azimuth angle. It is conjectured that the reason why the thrower's movement is asynchronous with the hammer's movement by approximately half a turn is to accelerate the hammer head in a manner similar to the way that the amplitude of a pendulum increases when it is pulled upward by a string against the downward movement of the swinging weight.     

浅论小说叙事视角的三种类型

小说的叙事视角,长期以来是文学创作者和文学评论者的关注热点.综观对视角讨论的文章,孰优孰劣的讨论占了多数.评论者的声音占据了读者的耳朵,这样具有明确指向性的讨论会混淆读者自身的认识.本文拟从小说叙事的三种视角类型入手,以期对小说视角问题有个清晰的认识.     

On-line real-time path planning of mobile robots in dynamic uncertain environment

INTRODUCTION Path planning of mobile robots is one of the key issues in robotics research on the problem of a robot finding a collision-free path from beginning to goal in the presence of obstacles. Depending on the envi- ronment surrounding the robot, it can be classified as follows: (1) Path planning for static obstacles in com- pletely known environment; (2) Path planning for static obstacles in un- known or partially known environment; (3) Path planning for dynamic obstacles in com- p…     

在数控车床上调用子程序加工盘形螺纹的方法

盘型螺纹特点是其径向尺寸远远大于轴向尺寸,并在端面上加工出方牙螺纹,由于螺纹的旋向由外向里,其螺旋线由大变小。因此将它用在自定心锁紧方面。用数控车床调用子程序加工盘型螺纹能充分发挥数控车床优势。     

助动词研究综述

助动词的研究自20世纪60年代以来,语言学界有过很多讨论和探索,各家也提出过自己的一些意见。对于助动词与副词、动词的区别、“助动词 动词(形容词)”结构以及助动词的下位分类、句法结构等语言学界也有许多研究成果。     

论周作人的性爱观

在20世纪初提倡女性教育的社会思潮下,基于自己特殊的生活经历,并受与谢野晶子与蔼理斯等影响,周作人开始进行相关女性觉醒题材的文学翻译和创作。其提倡从科学的角度来看待性爱,认为应该尊重性爱的个人性,不仅社会无权任意干涉个人性行为,父母也不能对孩子的恋爱和婚姻进行干涉。他剥离了人们强加于性爱之上的种种道德束缚,引导人们正确认识性爱。周作人的思想对于帮助中国女性从封建道德的束缚下解放出来无疑具有重要意义。     

投篮命中率的理论计算分析

文章提出二维空心投篮数理模型,通过解方程给出定解条件下投篮角的数值解,由此得到给定点投篮下的最佳投篮速度和截止投篮速度,并由计算结果进一步分析了不同投篮速度区间对应的投篮弧线,最后定量分析给出投篮距离和高度对投篮命中率的影响.     

国外教师情绪研究的视角转换与启示

自20世纪80年代以来,教师情绪逐渐得到研究者的重视,成为多学科研究的对象。这些研究表现出较为明显的阶段性特征,在第一阶段,研究者倾向于把教师情绪作为教师个人的内部心理特征,旨在确立教师情绪在教育中的价值;在第二阶段,研究者侧重从社会关系层面看待教师情绪,积极关注社会关系、政策改变与教师情绪体验之间的联系;在第三阶段,研究者开始把教师情绪的社会文化特征纳入研究之中,侧重从权力关系、情绪规则等研究教师情绪的塑造、转换和抵制。