The role of the great toe in balance performance.

The objective of this study was to evaluate great toe function in maintaining static and dynamic balance. Correlation among great toe length, body height, and balance performance parameters were also investigated. Thirty females (aged 22.1 +/- 1.9 years) were tested in two great toe conditions: unconstrained and constrained. Balance testing was done in the following order: (1) static balance, single-leg stance with right or left foot, eyes open or closed; (2) static balance, stance with both feet, eyes open or closed; (3) dynamic balance, left/right or forward/backward, rhythmic weight shifting; and (4) dynamic balance, target reaching test, eight targets within 90% limit of stability. Significant differences were found in sway velocity between the two toe conditions with eyes open or closed in single-leg stance (p < 0.05). No difference was found between the two conditions while standing with both feet. For rhythmic weight shifting, significant differences in sway velocity were found in toe conditions and in weight-shifting directions (p < 0.05). As to target reaching, significance was only noted in directional control scores. Great toe length was correlated with subject's height (r = 0.553, p < 0.05). Our results indicate that constraining the great toe deteriorated the subjects' single-leg stance performance and worsened the directional control ability during forward/backward weight shifting. The importance of the great toe in balance may be taken into account in toe amputation or transfer in the future.