Aim: The purpose of this study was to examine the validity of physical activity by a triaxial accelerometer which was developed in Japan recently. Subjects and Method :Ten healthy young students were studied in this study. They wore a triaxial accelerometer during their daily activities, and their physical activities (lying, sitting, standing, and walking) were videotaped. We examined relationships between the time measured with a triaxial accelerometer and that measured with video camera, and also analyzed the errors between the two measurements by Bland-Altman analysis. Results: The relevance between the two measurements showed a very strong correlation in all measurements. There were no additional errors among supine, standing, and walking but there was additional error in sitting position. There were no proportional errors in all four positions. Conclusion: The validity of physical activity measured by a triaxial accelerometer newly developed was suggested in this study.
A stairway in homes is an important structure for movement between floors. However, the number of fall accidents on stairways is very high in Japan. The present study aimed at investigating the dimensions of safe stairways especially by subjective assessments and three-dimensional motion in both sexes and three age’s groups. Eighteen healthy men and women aged between 21 and 75 years climbed up and down five kinds of stairs at different dimensions (rise and tread of a step). While going up the stairs, the height of a step influenced the track movement of their toes, which decreased distances between the toes and edge of the stairs, especially in the elderly group. Furthermore, the female group trended to feel more subjective strain with a larger height of a step. While going down stairs, a smaller tread of a step decreased the contact area of the soles on the surface of the step. These findings suggest that requirements of stair’s dimensions for preventing fall are different for climbing up and down, and for users of different ages and sex.