Abstract
[Purpose] The purpose of this study was to investigate the effect of aging on hallux flexor activity, and the relationship of physical center of mass deflection with hallux flexor activity during response to a backward perturbation. [Subjects] Sixteen community-dwelling elderly individuals and ten young individuals participated in this study. [Methods] A backward step movement was induced by perturbation, and abductor hallucis activity and deflection of the physical center of mass were measured. Two-way layout analysis of variance was performed, with age and step phase as variable factors. In addition, we analyzed abductor hallucis activity and its relationship with deflection of the center of mass. [Results] We found that age and step phase were associated with abductor hallucis activity. Further, anteroposterior acceleration of the pelvic center of mass showed a significant negative association with abductor hallucis activity during the perturbation response. [Conclusion] Our findings confirm that abductor hallucis activity during response to a backward perturbation is high in the elderly, and this suggests that the stability of the pelvis is associated with abductor hallucis activity.
