The Analysis On The Mechanical Test Of Female Javelin On Last Force And Left Support

Research purpose:By using the biomechanical research method and the experimental methods of Kistler three dimensional measures the strength platform and the flat photograph, this paper studies the excellent women javelin athletes' technique of the final effort to prop up from the left side in Shandong province, and expanded a new field of 3D mechanics examination of javelin athletes' final effort to prop up from the left side. By studying the mechanics and kinetics characteristic of the three most excellent women javelin athletes' final effort to prop up from the left side in Shandong province, it shows the sport rules and features of javelin throw's final effort to prop up from the left side. It provides a dependable kinetics index and parameter for the diagnose, improvement and exaltation of the techniqueof left side proping up as well as the javelin throw's teaching and training, which makes the javelin's theory more systemic and scientific. The reseach methods includes the literatural and documentary method, expert consultation method, 3D measure dint set to measure a dint method, imageanalyzing method and mathematical statistics method. Here are the conclusions.Firstly, the research of experimental methods: (1) As the cushion medium of the dint set's buffer of the surface lie, it is suitable to use the plastic skin about 2 cms, and to fix with the screw. (2)The time for the dint set to sample is 10s, which is more benifit for the athletes' preparation, data collecting and photographing. (3)The sample frequency of the dint is set to be 1000Hz and the photographing frequency 50Hz so that we can collect the number and data and reflect the kinetics and mechanics features more accurately.Secondly, the kinetics feature of t he final effort to prop up from the left side: (1) The athletes' final effort to prop up from the left side forms a double-valley up curve at the Z stalk, showing that they applies the brake powerfully and then move to the buffer when the athletes prop up to the ground form the left side and after that begin to stretch and toss the javelin with effort. There is a striking difference in the Fmax of the left side proping-up at the Z stalk between the excellent and second grade athletes and so is the speed changes when they prop up an ex-javelin to the Fzmax time, showing that the high level athletes' speed of running-up is quicker and the strength of left proping-up more powerful and the movement applies the brake) more effective. The time two excellent athletes spend from the moment they prop up from the left side to Fzmax has a great difference, explaining that there is difference in the skill of proping up from the left side between different athletes: one is a powerful s and the other is a much positive buffer movement. (2) During the final strength to throw javelin, the main period of the javelin speed is from the left foot landing on the ground to the start of stretch to throw jabelin. In this process the left leg delivers dint actively, and the right leg is placed in the dalliance after the power ends.This is a stage in which two feet land on the ground at the same time and prop to move, which is the most effective stage for throwing a javelin. In this process, the larger the excellent athletes'stretches strength is, the quicker its speed will be.Thirdly, the machanics characteristic of final effort to prop up from the left side: (1) On the X direction, the gravity of human body decendsquickly and the speed of javelin increases rapidly. At this time the momentum of human body changes toward the momentum of javelin to become an effective whip; on the Y direction, the gravity of human body increases gradually, the left side props up to stretch dint so as to increase the height and speed of the javelin.The quicker an athlete runs up, the greater the contribution of running up to the speed of javelin. However, in this experiment, among all the women javelin athletes, the best running-up speed is 5.5m/s, making a contribution of 20% to the speed of javelin. This makes a great difference with the world's excellent athlets about 30%. Therefore, it is suggested that in the following days' training, the athletes' speed of running-up should be paid more attention to. (2) At the very moment of throwing th javelin, the gravity of athletes' body center does not reach the highest number of its gravity, but the its speed on the Y direction attain the maximum, benifiting to the throwing speed of javelin. It is suggested that the throwing height should be increased as much as possible based on the fast enough speed in the following training. (3) At the last and most effective stage of throwing javelin, the sport trace of the athlete's left foot is a straight and even curve, while that of the right foot begins up form straight. The lifting of the right foot shows that the left leg is the main dint leg to prop up duing this stage and the right one is forthe stretch effort. (4) The step size of the two feet proping up the dint of this stage depends on the right leg's stretch and left foot' grounding time and range. The valid function point of Back bow in the exceeding machine skill is the left foot's location point, Left hip spot,the right shoulder point and the javelin-holding point.Finally comes the feature of movement trace of each in the final proping up the dint. (1) In the process of last dint, the athletes' Right flank hip 'speed on both the X stalk and Y stalk is higher than the left one. It shows that human body's whip on the machines does not make the arrow installs the axis as the whip stalk, butthe arrow installs the axi,Central shaft,Coronal axis three kinds of stalks. The athlets are suggested to make sure the three whip axis when throwing javelin but not just purse the afterward or sideward's latter directs to snatch surmounted the instrument , and they should have an appropriateexeeding apparatus exercise based on the different whip axis and catch the whole distance on the three whip axis so as to increase the whole whip function distance during the final dint.(2) In the last process, the quick grounding of left leg can quicken the formation of"left leg- left hip -right shoulder-javelin-holding point"and meantime enlarge the whip angle of Left hip angle,Right hip angle and the aggraandizement as well as the whole achievement distance of these apparatus.At the same time the left support should have buffer positively and prepare the musle stretch after the buffer in advance so that the left resistance support can be reduced and the achievement strength in left-backward tint period can be increased.(3) The last tint process takes the right leg grouding buffer's ending as the beginning and ends with the throwing of the javelin, among which, The tw o feet proping up period is the most effective one.