Examination of School Furniture by Three-dimensional Motion Analysis Change in elementary school children's movements and junior high school students' movements according to change in height of desks and chairs

摘要

The three-dimensional motions were measured for ten elementary school children and ten junior high school students who were using furniture for the school. The desks and the chairs used were the numbers of sizes from the second to fifth sizes of Japanese Industrial Standard, and they were wooden desks and chairs, the height were able to be adjusted. The measurement was based on the height of the desk and the chair of the proper sizes calculated from the stature of the children and students. The height of the desk and the chair was changed into three stages, those were the proper size, the minus one level size and the plus one level size of JIS. It assumed that the study scene in the school, movements of seating, standing up and carrying desk and chair were analyzed with three-dimensional motion analysis system. The movements were measured by putting on reflective markers to the vertex, acromion, radius, carpus, trochanter, tibia and ankle of the subjects. And the movements were taken of pictures with two CCD cameras. The result of this experiment was as follows. When sitting on a chair, the angle of the waist had become small in low height of the desk and the chair. At the same time, the subjects were bending their knees and stooped. On the other hand, at the movements of standing up from the chair, the amount of the movement of the waist and the shoulder had decreased by rising of the height of the desk and the chair. When the desk was carried backward, an upper and lower wiggle became small in a tall school child. In low height of the desk and the chair, many children and students answered that the waist and the leg were tired.