抄録
The area of the center of pressure (CP) during various activities and the area of CP during maximal voluntary shift to the right, left, back and forth were measured by stabilometry in normal subjects in whom several postures and visual conditions were combined in different ways. When the areas are expressed by circles of πr2 and πR2, the ratio of r to R indicates the capacity of stance correction. The mean value with eyes closed changed from 0.45 for one legged stance to 0.04 for standing with feet apart. The logarithm of r/R decreased lineraly as R increased. Opening the eyes decreased the value of r/R to a fixed ratio irrespective of stance, it was 0.27 when the subject was standing still. Tilting the head increased r/R 1.6-1.9 times irrespective of the stance. However, turning the head or flexing the neck raised the r/R more when the subject was standing with feet apart than when he was standing on one foot. The present study suggests that the value of r/R indicates the ability to regulate stance by the spatial coordinates in the brain. It may be useful in investigations of the regulation of stance to think of the CP area as a scatter on a mark.
