2014 年 61 巻 3 号 p. 3_97-3_104
In recent years, people sitting for many hours have some problems: pressure ulcer, congestion and etc. This study aims to clarify the optimal cushion and back angles to prevent these diseases by measuring the changes in lower limb blood flow in the cushion and back angles. The result shows the shear and compressive forces between the buttock and the seat, fluctuated by the cushion and back angles, affect the blood flow. This study also derives the optimal angles by the weighting factor method using the contribution ratio of these forces in blood flow as the weighting factors. Additionally, this study confirms the validity of the contribution ratios and the derived optimal angles. The result indicates a proportional relationship between the blood flow and the weighted sums of the forces, calculated using the contribution ratios, and the highest blood flow measured with the derived optimal angles.