Most of aged have a problem about one's knee trouble. It is important that the problem grow into lying in the aged. A daily rehabilitation-treatment is indispensable to solve the problem. In the past time, most of the treatment effect was estimated by observation of a physical therapist or a angle scale. So the exactitude of the estimation was kept to low level.
　In this study, new methods for measurement and estimation of knee motion angle are developed. In these methods, the angle is measured and estimated objectively. One of them is a method for medical center.
　The other is a method for residence. In the first case, the angle is measured and estimated by a image which is taken by a digital camera.
　In the second case, the angle is measured and estimated by LED and photo transistor which are constructed in a arched handrail. The measurement and estimation are easy in the both methods. The exactitude of the estimation are also kept higher level.

DESCENTE SPORTS SCIENCE Vol.18/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE