Abstract
It is clarified based on the analysis of foot movement in walking that there is very little danger of stumbling if the height of difference in level is within 5 mm. Sensory and perceptual evaluations concerning the pain at stumbling and the danger of tumbling were quantified as evaluation scales by means of a sensory test. Then proper physical quantities corresponding to the scales were established using a newly-depeloped measuring apparatus. Finally the relationship between the scales and the quantities were presented as evaluation indexes of the safety of difference in level.
