PURPOSE: The purpose of this study was to investigate the mechanism of the fluctuation in the shear force applied to the buttocks. METHOD: The subjects were 11 healthy adult men without leg or trunk diseases. The amount of force applied to the buttocks was measured by using a force plate, and a pressure and shear force sensor was used to measure the timing of the force applied to the back support. RESULTS: The average value of the shear force applied to the buttocks was 9.4 ± 2.4 (%BW) in the initial upright position (IUP), 9.3 ± 1.2 (%BW) in the fully reclined position (FRP), and 15.0 ± 2.9 (%BW) in the returning to an upright position (RUP). Significant differences appeared between the RUP and the other positions. CONCLUSIONS: The results of this study suggested that the adjustment of the axes of rotation of the back support and trunk-pelvis and the release of the remaining shear force after the back support is reclined are important for the prevention of decubitus ulcers.
PURPOSE: The purpose of this study was to investigate the mechanism of the fluctuation in the shear force applied to the buttocks. METHOD: The subjects were 11 healthy adult men without leg or trunk diseases. The amount of force applied to the buttocks was measured by using a force plate, and a pressure and shear force sensor was used to measure the timing of the force applied to the back support. RESULTS: The average value of the shear force applied to the buttocks was 9.4 ± 2.4 (%BW) in the initial upright position (IUP), 9.3 ± 1.2 (%BW) in the fully reclined position (FRP), and 15.0 ± 2.9 (%BW) in the returning to an upright position (RUP). Significant differences appeared between the RUP and the other positions. CONCLUSIONS: The results of this study suggested that the adjustment of the axes of rotation of the back support and trunk-pelvis and the release of the remaining shear force after the back support is reclined are important for the prevention of decubitus ulcers.