A case report of female middle-distance runners : form of running

Abstract

This study was designed to analyze a world class and a Japanese middle-distance runners in women's 800 m finals of the international athletic games based on kinematic data, and to get insight into the basic middle-distance running technique. The performances of Qu yunxia, the world record holder of female 1,500 m and Kumiko Okamoto, the Japan record holder of female 800 m were video-taped with a video camera operating at 60 Hz with exposure time of 1/500 and 1/1000 s. Selected kinematic variables of the center of gravity (C.G), the segment endpoints and rotational energy of the lower limbs were investigated. Some differences of performance were found between Qu and Kumiko in running form. The C.G of Kumiko's up-down motion on vertical direction was about 14% larger; her deceleration in horizontal direction was 48% larger and her up-down motion of C.G of the feet was about 26% than Qu. The larger action of the foot breaking contact with the ground of Kumiko caused a greater loss of horizontal velocity of C.G. The larger flexion of the knee-joint of Kumiko consumes the greater rotational energy than Qu during the recovery phase.