[Force plate analysis of ascending and descending stairs]

Six characteristic points including maximal and minimal points of the vertical components, and antero-posterior components were determined by digitalization of floor reaction curves in ascending and descending stairs. In cases with hip or knee disorders, lengthening of phases of the characteristic points were observed in ascending stairs, while shortening of phases were seen in descending stairs. The maximum of vertical forces on affected legs decreased in ascending and descending stairs. In cases with hip disorders, characteristic points of sound legs in early stance phase were different from those of normal subjects. In cases with knee disorders, increase in vertical forces during mid-stance phase was observed.