Fundamental Studies of Hitting Movements -Flectromyographic study on Both Handed Backhand-ground strokes of Tennis-

打球動作は上肢の内外旋を併なう動作様式の運動である｡テニスのバックハンドストロークは主として上肢の外旋を併なう打球動作であることはいうまでもない｡しかし,近年,内旋側上肢が関与する両手によるバックハンドストロークが多用され始めている｡今回は,外旋側の上肢に対して内旋側のフォアハンド的役割りを演ずる他方の上肢が打球にどのような係わりを持つのかを筋電図とV.T.R.を中心にしてその実態を明らかにし,指導の際の基礎資料を得ようとした。The purpose of this study was to investigate the correlation between right and left arm, lower and upper body by using VTR set, force plate and ENG analysis. Four female and one male served as subject in this study (They are right handedness). Sixteen muscles were tested as follows: right and left side starncleide mastoideus, right and left posterior deltoidues and anterior deltoidues, right and left biceps brachii and triceps brachii, left side of erector spinalis and interrossei dorsales, righ side of abductor digiti minimi and rectus abdominies. Force-plates were used to record the vertical components of both legs. 1) The discharge patterns of upper limbs mustles at left handed fore-hand stroke and left arm majored both-handed back-hand stroke were similar to that of normal both-handed back-hand stroke. 2) The normal both-handed back-hand strokes owed to right arm rotators and left arm internal rotators