The importance of the great toe in balance performance

The objective of this study was to evaluate function of the great toe in maintaining human static and dynamic balance. Correlation among the great toe length, body height and balance performance parameters were also investigated. Thirty female subjects (aged 22.1±1.87 years) were tested in two great toe conditions, unconstrained and constrained. Balance testing was done in the orders listed: 1) static balance, single leg stance with right/left foot, eyes open and closed; 2) static balance, both feet, eyes open and closed; 3) dynamic balance, rhythmic weight shifting, left/right and forward/backward; 4) dynamic balance, target reaching test, eight targets within 90% limit of stability (LOS). The results demonstrated significant differences in sway velocity between the two toe conditions with either eyes open or closed in single leg standing (p<0.05). No difference was found between the two toe conditions while standing with both feet. For the rhythmic weight shifting, significant differences in movement velocity were found both in toe conditions and in weight-shifting directions (p<0.05). Significant interaction was also found between the toe conditions and the weight-shifting condition. As to target reaching, significance was only noted in directional control scores but not in reaction time (p=0.689) and movement velocity (p=0.17). Correlation results revealed the great toe length was only linearly correlated with subject's height (r=0.553, p<0.05) but not the others. Our results indicated that constrained great toe deteriorated the subjects' single leg stance performance and worsened the directional control ability during forward/backward weight shifting. Great toe amputation individuals will be recruited in future testing for a more conclusive summary of the importance of the great toe in human balance.