Relationships of the Mechanical Axis Inclination Angle and the Motions of the Trunk and Pelvis during One-Leg Standing in Healthy Young Persons

Abstract

[Purpose] The purpose of this study was to investigate the standard value of the mechanical axis inclination angle (MIA) during one-leg standing, and clarify the relationship between MIA and the motions of the trunk and pelvis. [Participants and Methods] Twenty-four healthy young males (n=12) and females (n=12) participated in this study. MIA and each joint angle of the trunk and lower limbs were measured with the subjects performing one-leg standing with or without a lateral wedge insole. [Results] MIA of females was significantly greater than that of males. MIA correlated with both the trunk and pelvic angles. No significant difference was found between with or without the lateral wedge insole. [Conclusion] There is a standard value of MIA in healthy persons, suggesting there is a postural strategy based on the trunk and pelvis to keep MIA constant when knee joint alignment changes during one-leg standing.