Abstract
Every previous literature points out that stair use requires a lot of energy, and that gentle stairs are desirable from the viewpoint of work load. However, such a requirement is in conflict with the condition of present domestic stair dimensions because it is usually steeper stairs that dwellings have because only a narrow space is available. In this report, the relationship between stair dimensions and rate of energy expenditure was investigated in order to decide a maximum allowable pitch for domestic stairs. Three experimental stairs were used to produce various dimensional combination of tread going and riser height; three subjects climbed up and down the stairs, and their heart rate was used as a measure of the energy requirements. Its relationship with the oxygen consumption was established in advance by treadmill walking test. A continuous climbing-up of a high rise office building also provided data on the change of heart rate during stair use. A careful examination of obtained data suggests no definite maximum pitch for domestic stairs; the hypothesis that there exists a limit of allowable pitch from energy expenditure is applicable only to public ones where a walking speed is imposed by other users. Present study gives a conclusion that other factors such as safety or usability determine necessary dimensions for domestic stairs.
