Motion analysis with exploratory factor analysis -an investigation of dynamic sitting balance-

[Purpose] The aim of this study was to investigate whether exploratory factor analysis could classify the patterns of joint motions during a task of lateral dynamic sitting balance. [Subjects] Forty-eight healthy adults (29 males and 19 females) were recruited for this study. [Method] We measured the center of pressure (COP) and joint motions during maximal lateral weight shift in sitting. The joint motions were classified with exploratory factor analysis. Furthermore, we used multiple regression analysis to examine which factors were significantly related to the amount of COP displacement. [Results] We found that the joint motions were classified into 4 types of pattern by the exploratory factor analysis (accumulated contribution ratio=42.5%). The main factors extracted by multiple regression were factors that were related to postural reaction. [Conclusion] Exploratory factor analysis could classify joint motions and could objectively evaluate movement patterns during a task of lateral dynamic sitting balance.