Effect of Ageing on Quadriceps Muscle Strength and on the Forward Shift of Center of Pressure during Sit-to-stand Movement from a Chair

Abstract

The purpose of this study was to investigate the effect of ageing on body sway during sit-to-stand movement from a chair and on quadriceps muscle strength in the elderly population. A total of 275 community dwellers volunteered to participate in this study. All subjects signed an informed consent statement prior to participating in this study. They were required to be able to perform a sit-to-stand movement from a chair independently. The postural sway for the subjects during the sit-to-stand movement from the chair was measured using a stabilometer. The analog signals of the subjects' center of pressure in the anterior-posterior direction (%Y-axis) derived from the stabilometer were recorded. The maximum isometric muscle strength of knee extension was measured using an isometric dynamometer at 90 degrees flexion of the knee joint. Our results demonstrate that as age increased, lower extremity muscle strength decreased, and forward shift of the center of pressure also decreased. It is possible that the elderly subjects could not use their propelling power because of decreased lower extremity muscle strength. Therefore, the forward shift of the center of pressure of elderly subjects also decreased causing them difficulty in standing up from a chair. Therefore, we believe that we there is a need to educate elderly people about accurate sit-to-stand movement and the importance of lower extremity muscle strength exercise.