On the basis of analyzing the complex pockets with monotony chain technology, the maximum retraction motions of a given complex pocket can be estimated and the number of tool retraction motions can be minimum by using this method.

Adopted the world-advanced APSA system,with the assistance of the method of three-dimension analysis of sports biomechanics,this study analyzed the jump action techniques of the top sportsman in the word wide.

Storage of elastic energy in human leg muscles;