Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 1999: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1998: ¥3,000,000 (Direct Cost: ¥3,000,000)
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Research Abstract |
In order to clarify the relationship between sitting comfortableness and the individual bodily characteristics, the back-shape, anteflexional stiffness of torso and sitting posture were measured. Developed back-shape measurement system consists of a sliding gage with linear potentiometers aligned 30 mm apart like a comb. Change in back-shape that may cause due to contact of the probes can be reduced within the range of tolerance by pushing the probes in two steps. The back-shape of thorax region is not changed despite of change in posture, but exhibit large individual difference. The anteflexional stiffness of lumbar joint and hip joint were estimated independently by measuring resistive torque of each joint when torso was forced upright, while thigh was kept horizontal and knee was flexed to 30 degrees. Subjects with large lumbar joint stiffness have tendency to sit deeply and stand their pelvis, but on the other hand, those with large hip joint stiffness sit in front and tilt their pelvis. The sitting posture was measured using a model matching method; The angle of body segments were not measured by attaching markers, but automatically fitted by geometric model of human with textures. By using these newly developed methods, the mechanism of comfortable sitting for an individual was clarified as follows; (1) sitting position is determined by hip joint stiffness and back-sharp of thorax region, (2) pelvis angle is determined by the sitting position, (3) thorax angle is determined by the sitting position and the back-shape of thorax region. Consequently, comfortable sitting posture is selected individually by the bodily factors, back-shape and hip stiffness.
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