The Study of Relationship between Toe and Dynamic Postural Control

Abstract

The purposes of this study were to examine the roles of toe in dynamic postural control during horizontal and vertical movements, and to elucidate the relationship between dynamic postural control and toe grasp power in healthy young subjects. Three kinds of non-weight bearing insoles, that without weight on a great toe, that without weight on the second to fifth toes, and that without weight on all toes, and an insole of weight bearing were prepared. Center of foot pressure was measured during forward functional reach, and body sway was measured during crouching and standing motions as an index of dynamic postural control during vertical movement. Both in horizontal and vertical movements, a great toe exerted the function of supporting the shifted center of gravity, and the second to fifth toes had the function of re-centering the shifted center of gravity. These suggest a possible role of a great toe and the second to fifth toes in dynamic postural control during horizontal and vertical movements. Toe grasp power of a great toe and the second to fifth toes were measured separately by the hand-held dynamometer improved for toes. Analysis of the relationship between dynamic postural control and toe grasp power suggests that toe grasp power may reduce the body sway area. It is also suggested that toe grasp power may have an effect on dynamic postural control during vertical movement, and that strengthening of the toe grasp power may potentially decrease the risk of falling.