Abstract

This study was designed to analyze the spiking motions of international-class players by normalization and averaging of the three dimensional kinematic data, and to provide these information with clarifying the basic volleyball spiking technique. Soviet, Cuban, Polish and Japanese male players who participated in the 1981 World Cup Volleyball Games held in Tokyo were filmed at 100 f.p.s. with two 16 mm cinecameras. Twenty-three spikings performed successfully were selected for the analysis, and were digitized from the start of the approach run to the end of the swing in the air. Twenty-four 3 dimensional coordinates for the segment endpoints and ball were computed by the Direct Linear Transformation Method. The kinematic data werew obtained from the 3D coordinates. The locations and directions of the CG pathways were different from player to player. Therefore, the 3D frame of reference during the movement phase was specified, where X, Y, Z axises indicate the right-leftward, for-backward, and up-downward directions respectively. After the rotation of the coordinate system on the horizontal plane, the averaged spiking motion from 23 players was obtained by normalization and averaging of the displacement data for 21 segment endpoints. The motion seemed to represent the basic volleyball spiking technique, because the analyzed spikings were successful spikings performed by international-class players, where the average finger height at impact was 3.18 m, and the average ball velocity immediately after impact was 22.37 m/s. Verf.-Referat