Abstract
The purpose of this study was to investigate the relationship between the backrest of a chair and the position of the pelvis on the peak load value at the ischium and the shear stress in sitting on a chair, using an instrument to measure pressure distribution and an experiment model. Ten healthy male subjects (mean age 22.4±2.3 years old) participated in the study. The results showed the peak load value to be significantly lower when the trunk of the body leaned against the chair's backrest, and that it became lower when the pelvis was moved forward and the trunk leaned against the backrest. In addition, the estimated value of shear stress was 1.8±0.7 kgf in the standard position, 2.2±0.6 kgf in the 5-cm forward position, and 2.2±0.5 kgf in the 10-cm forward position. The shear stress value was higher when the pelvis was moved forward. These results suggest that leaning the trunk of the body against the backrest of a chair with the pelvis close to the backrest might be effective for preventing pressure ulcers, because the peak load value on the ischium and the shear stress were lower than they were in the other positions.
