THE COMPOSITIONS OF RELATIONSHIP BETWEEN APPROACH SPEED AND CENTRE GRAVITY (CG) IN THE FLOP STYLE

Abstract

ABSTRACT - By examining two excellent men high jumpers, aiming at explaining relationship between approach speed and the height of the body is centre of gravity, so as to afford theoretical basis for coaches and athletes to grasp reasonable sport skills. METHODOLOGY - The High speed Cameras (Model:LBS - 1 GA,speed: 100 frames persecond), Pulling-force sensor (Model : HYL-1) and Remote EMG meter (Model: Multi-Telemeter 551, Japan made) were simultaneously operated by means of synchronous Signal Generator. RESULTS AND DISCUSSION - The compositions of relationships between approach speed and centre of gravity (CGJ in the plop style when taking off are as following: 1. Speed relatively low, CG relatively high. 2. Both speed and CG are relatively lower. 3 Both speed and CG are higher. 4. Speed much higher, CG relatively lower. A very effective take-off can be made by this approach method. However, a deep flexing of knee, which, if is overdone, might affect an explosive extension, is needed. This approach method is necessary for gaining high scores, but it is too difficult to perform. As to the relationships between approach method and CG, there are two elections. One of them is keeping a relatively lower CG, which inevitably causes an negative vertical velocity when taking off. The other is slightly heightening CG to reduce this negative vertical velocity. To solve the above problem, one should organise approach method and CG height the most excellently, as is different according to different person.