座位腕運動時の姿勢制御に関する研究

抄録

Modern humans spend a considerable length of time everyday in a seated position, working, driving, relaxing, etc.. Little is known, however, regarding the neuronal control of human body balance while seated. There are many reports of the neuronal control of body balance while standing, but few studies of the neuronal control of body balance while seated. We examined the functional role of various muscles during upper limb movements while in a seated position. Twelve subjects, between 21 and 49 years of age, volunteered to participate in this investigation. None of the subjects presented with signs of neurologic disorders. Electromyogram (EMG) activities were recorded from the arm, shoulder, back, abdominal, and leg muscles with bipolar surface electrodes. Subjects sat on a chair and performed various upper limb movements at different speeds. We also recorded the force exerted by the back. All data were synchronized using a pulse generator. The results indicated that 1) various shoulder, trunk, and hindlimb muscles control body balance during arm movements while in a seated position, 2) EMG activities (the intensity and timing of EMG bursts) of the shoulder, trunk, and hindlimb muscles depended on the direction and speed of the upper limb movements. The results of the present experiments indicate that neuronal control of the shoulder, trunk, and hindlimb muscles is required to maintain body balance while in a seated position. [J Physiol Sci. 2008;58 Suppl:S194]