支持基底面を基準とした有効支持基底面の割合における足幅条件間差および日間信頼性の検討

抄録

Humans maintain a center of pressure (COP) that is virtually united in a vertical direction of center of gravity to maintain an upright standing posture in the base of support (BOS). However, the COP cannot move until there is an edge of BOS. Actually, it can move only until there is an edge of the inside functional BOS [limits of stability (LOS)]. This study aimed to examine the difference between the foot breadth (0cm, 10cm) and the day-to-day reliability in a rate of LOS for BOS (LOS per BOS: LPB). A pressure sensitive mat was used to measure the BOS, and a force platform was used to measure the LOS. The former was placed on the latter. The subjects were 11 healthy male students. After measuring the BOS, they measured the LOS, which moved the COP to form a circle without changing the foot breadth. The above measurements were performed for duration of 5 straight days. Two-way ANOVA showed no significant difference in the interaction; however, there was a significant difference in the main effect of the breadth factor. A multiple comparison test demonstrated that the LPB was lower in 0cm than in 10cm throughout the duration of the study. In addition, the intraclass correlation coefficients were > 0.67 for both foot breadths. Our outcomes demonstrated that not only BOS and LOS but also LPB increased the foot breadth and differed little from the interday variation.