著者

伊東 太郎

出版者

聖トマス大学

雑誌

紀要 : 人間文化 (ISSN:13450131)

巻号頁・発行日

vol.9, pp.1-57, 2006-03

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In initiation of the volitional movements from an upright standing position in humans, a focal movement cannot be executed until the position of the center of body mass (CM) has reached a given point. In step initiation, it is generally known that the anticipatory activities of the center of pressure and both the tibialis anteriors muscles emerge prior to the execution of the intended forward-oriented movement from a standing position. These phenomena are thought to play a role in transferring the position of the CM to the necessary conditions to initiate a step movement as the anticipatory postural adjustments (APA). It is not clear whether and how the APA change according to the motor perform-ance. The purpose of this study was to elucidate the relationship between the APA and intended movement through the experiments by the use of the electromyographic and kinetic methods. Consequently, it was confirmed that the APA parameters (the amplitude and/or duration parameters) have a close connection with the changes of the velocity, propulsive force or instability in the intended movement. This article provided evidence that the APA play a part not only in shifting the CM for initiating movement, but also in assisting the increase of the motor performance. Moreover, this suggests that the intensities of the APA parameters are decided centrally according to the parameters of a focal movement in feed forward manner. The knowledge obtained from this study can be applied to the selec-tion of training muscles in the field of sports exercise or the prevention of falling and stumbling by the postural dyscontrol in the elderly.