By studying the SSC exercise of the muscle of the take-off leg in the process of back layout,the purpose of this paper is to provide a theoretical reference for the guidance of the special strength training of the high jumpers takeoff leg and for raising their high jump performance in China.

The results reveal that the poor effect of male volleyball players single foot takeoff accounts for their weak eccentric contraction capacity of takeoff leg s knee extensor and poor swinging technique of swinging leg, which lead to long buffer time and slow buffer speed of takeoff knee, as well as slow swinging speed of swinging leg.

172 seconds,the value of reactive characteristics of take-off leg s muscles is 35.

In virtue of analyzing frog s jumping,this paper designs a hopping leg,then abstracts the leg and find a system model composed by two mass bodies and a spring,finds the qualification and the equation of jumping.