摘要
掷铁饼是单手握持铁饼站在投掷圈后缘,经旋转后充分发挥全身的力量,以最快的出手速度和最适宜的出手角度,将铁饼从体侧后方经体侧向前掷出,并尽可能获得远度的比赛项目。20世纪80年代中后期是我国掷铁饼水平迅猛发展的黄金时代,1992年著名铁饼运动员肖艳玲掷出了71.06米的好成绩,男子铁饼也再破亚洲纪录,但近几年由于训练手段的单一和后备人才的断层,成绩出现整体滑坡,在投掷项目上,我们必须从科学训练入手,研制和开发适合我国运动员的体育专项训练器械,这成为目前亟待解决的关键问题。
为了适应目前这种需求,改进传统的训练评价手段,从解决运动练实践中的难点和关键点出发,应用现代科技理念及手段,我们研制出了数字化铁饼三维信息采集系统,该系统包括一个数字化铁饼原型样机和数字化铁饼三维信息采集系统的专用软件,该系统包括一个数字化铁饼、USB连线、上位机软件和一台PC计算机,其中,数字化铁饼由上、下壳体、金属圈、电路板、加速度传感器、角速度传感器、数模转换器、微处理器、FLASH存储器、USB接口等设备组成。该系统最大量程为±14000牛顿;单维标定误差≤1.5%F.S.(典型);最大过载能力为200%;采集频率100赫兹;分辨率0.1% F. S;每次数据采集时间为15秒;最大可存储投掷次数13次;采集组数1～13组;内置9V充电镍氢电池;工作温度- 40摄氏度～80摄氏度。
对铁饼进行了两次现场测试,针对第一次测试中采集到的数据与出现的问题,进行了分析与总结,提出了改进措施,改进了数字铁饼的内部结构。在改进数字铁饼后,在河北省田径队对3名铁饼运动员(1名健将级、2名1级)进行了第二次的测试,测试的同时使用两台JVC9800摄像机进行了拍摄,并使用DLT三维辐射框架进行标定,在运动学方面,对测试结果应用APAS三维运动解析系统进行解析。根据数字化铁饼三维信息采集系统采集到的数据与APAS三维运动解析系统解析出的数据,对测试运动员的技术动作进行了深入的分析,分析结果表明弓健与李冰的技术比较相似,李冰的铁饼加速度波动较弓健的大,郭文鑫的技术动作在左脚着地到铁饼离手阶段与弓健和李冰有着较大差异,主要是郭文鑫在投掷铁饼时,左脚着地后,出现了一个停顿,表明郭文鑫在最后用力阶段用力过早,需要从技术上进行改进。从3名测试运动员最大加速度来看,弓健的加速度最大,也就反映出弓健的爆发力在3名运动员中是最好的,李冰与郭文鑫的爆发力相差不多。从测试的成绩来看,3名测试运动员爆发力绝对值的大小与运动成绩没有高度的相关性,成绩的高低还与作用力持续的时间有关。从出手后铁饼的旋转稳定性来看,李冰的铁饼的晃动最大,弓健次之,郭文鑫在铁饼出手后,摆动最小,最平稳。
两次的现场测试、充分检测了铁饼的使用效果,并且对测试结果进行了深入分析,分析表明该系统能够时实采集运动员掷铁饼过程中的加速度信息和角速度信息。能够测得人体对铁饼在X、Y、Z三个方向上加速度及变化曲线,能够测得铁饼在X、Y、Z三个轴方向上的角速度及变化曲线。通过USB接口方便数据的存储、读写和打印相关文件。该系统反馈速度快;可实现无妨碍、无损伤检测;测量安全可靠;可连续进行测量、记录及显示;可用电脑对测量数据进行运算、存储、信息处理和输出打印;能够单独测量,并能与其它仪器的同步测量。
通过该系统采集到的数据,可以快速的反映出铁饼运动员的投掷技术的差异,为运动员改进技术、提高成绩提供科学根据,为教练员、运动员科学训练提供一种科研仪器和监控系统。体育科研工作者可以借助此仪器和此种测量手段,去探索铁饼投掷技术的新理论,去发现新的规律,进行改进和完善铁饼投掷项目的技术最佳化问题。
It is hold discus singlehandedly and stand in the behind of the circle, give full play to the strength of whole body after rotating to discus throw, gain the most suitable speed and angle, throw the discus from rear of the body side and before the body side direction out, and got the event of degree far as much as possible. Discus throw at Golden Era when the level was developed rapidly in our country in the mid to late 1980s of the 20th century, famous discus athlete Xiao YanLing threw out 71.06 meters of good results in 1992, the men's discus throw broke the Asian record too, but because of lack of training method and discus athletes in recent years, the achievement comes down wholly, in order to obtain the break-through on the discus throw, we must proceed with scientific training, develop special sports apparatus which suit the athlete of our country and train, this becomes the key problem which we must solve at present.
In order to adapt this kind of demand at present, improve traditional training and evaluation, solve the problem from the difficult point and key in practice, use modern scientific and technological idea and methods, we have developed the three-dimensional digital discus information collection system which includes a digital discus, USB connecting line, position machine software and a personal computer. The digital discus is made up of the higher and lower shell, eyelets, circuit boards, accelerometer and angular rate sensor, A/D, processor, FLASH memory, USB interface, etc. The largest measurement range is±14000N. One-dimensional error≤1.5% F.S. The greatest overload capacity is 200%. Gathering frequency is 100Hz. Resolution ratio is 0.1%F.S. The time of every data-gathering is 15 seconds. The largest number of throwing which can be saved is 13. It can gather the groups from 1 to 13 times. A 9V nickel hydrogen charge battery is installed within. Working temperature is–40℃—80℃.
We have carried on the on-the-spot test two times, base on the collection of the data in the first test, we have analysed and summarized, has proposed improving methods, has improved the inside structure of the digital discus. After improving digital discus, In the track and field team of Hebei ,carry on test of the second time to 3 discus athletes, use two JVC9800 camera and use DLT three-dimensional radiation frame, in kinematics , use APAS three-dimensional sports analyze system to analyze the test result. Based on the collected data from the three-dimensional digital discus information collection system and the APAS three-dimensional sports analyze system, having carried on deep analysis to technological movements which tested the athlete, the analysis results indicate that it is more similar between Gong Jian and Li Bing in technology, the acceleration curve fluctuation of Li Bing is more than Gong Jian, from left foot lands to release discus, Guo WenXin after the left foot lands , stop one while, indicate that Guo WenXin exerts oneself too early and needs to improve the technical. From the athlete's largest acceleration, the explosive force of the Gong Jian is the largest, the others are similar. According to results tested, it is not highly dependence between the absolute value size of athlete's explosive force and achievement, the level of the achievement still relates to time lasting in effort. According to rotation stability of the discus after throwing, the rocking biggest of Li Bing's discus, Gong Jian in taking second place, after Guo WenXin throwing the discus, it is minimum to swing, the most steady.
It has fully tested the effect of the digital discus through two times on-the-spot tests and has carried on the analysis deeply to the test result. It indicates that this system can collect the information of acceleration and angle velocity. This system can get the force signal of the athletes in real time during the complete process of athlete’s throwing of the discus. It can measure the strength and the curves of human body through the directions of X, Y and Z; in addition it measures the amount of combined force of every direction and the impulse in any period. It can get the angular speed and changing curves in directions of X, Y and Z axes; it also can save, read and print the associated documents with the help of USB interface. This system is high in precision and quick in reaction and is capable of realizing unimpeded and non-harmful experiment. It is safe and reliable and it can measure, record and display continuously. Computer can be used to calculate, save, process information and output and print, it can not only carry on measurement independently but also can take synchronous measurement with other instrument.
Though the collection of the data, it is can fast reflect the difference of technology, it offers the scientific evidence in order to improve technology and result, This system offers a scientific research instrument and monitoring system for coach and athletes in their scientific trainings. The sports scientific research worker can use this instrument and this measurement method to explore the new theory of technology, find the new law, improve and prefect the discus throw technological optimization.
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