| Summary: | 碩士 === 國立臺灣師範大學 === 體育研究所 === 90 === The volleyball-spiking jumps influence the height of spike and the balance of body in the flight phase. So the spiking jump is the important technique of volleyball spiking. Spike-jumping techniques will varying considerably according to factors as weather a hop jump (the feet step upon the ground simultaneously) or step-close jump (one foot steps upon ground, then the other foot) (Coutts, 1979), and approach speed and lengths of the last stride employed. Researchers have studied the effect of approach speed by designing different numbers of approach steps (Kayambashi, 1977) and last step lengths(Liu & Huang, 2001). Generally, male players prefer step-close jump, and female players prefer hop jump during volleyball-spiking jump take off. Coutts (1979) studied volleyball hop jump and step-close jump during spiking jump takeoff, he only reported the kinetic data and lack of kinematic data. The purpose of this study was to investigate the net muscle moments and works on lower limbs in two different volleyball-spiking jumps by inverse dynamics. A Kistler force platform (600 Hz) was synchronized with a Peak high speed camera (120Hz) to collect the volleyball jumping action. Sixteen volleyball players (8 males and 8 females) were served as subject for the study. The results revealed that No difference was found between two jumps on jump height and push-off time, hop jump have greater ankle and hip moment but a smaller knee moment than the step-close at the start of push-off,and the works done in knee joint during eccentric contraction were greater than ankle and hip joints in both two volleyball jumps. In addition, the hip has a greater work contribution on both hop and step-close jump.
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