The aim of this study was to propose a safe teaching method of Seoinage (shoulder throw technique) by comparing the motion and characteristics of skilled and unskilled practitioners. The following contents explain the findings:
① An analysis of Seoinage through stick figures reveals that the skilled practitioner lifts Uke (practitioner receiving the technique) with their hands while bending the knees and lowering their center of gravity. On the other hand, the unskilled practitioner, in order to lift the Uke, straightens the knees and attempts to complete the throw by bending at the waist.
② By analyzing the angle of the elbow of the Tsurite (lifting hand),the skilled practitioner demonstrated forearm support and stability. However, the unskilled practitioner tended to fully bend at the elbow and attempted to lift the opponent. Also, regarding the armpit angle of the Tsurite, the analysis found that when the skilled practitioner entered the lifting motion, the upper arm was level with the shoulder, allowing space in the armpit and stability. On the other hand, the unskilled practitioner applied the technique with a closed armpit.
③ When applying the Seoinage technique, the unskilled practitioner cannot control Uke with the upper arm, leading to a dangerous throw. Therefore, when instructing the Seoinage, it has been found that Uchikomi (technique repetition without completion) during practice is effective in order to create an image of lifting Uke and rotating with an effective use of the Tsurite.
