The effect of fatigued hip abductors on single-leg stance postural control and muscle control

[Purpose] the purpose of this study was to clarify postural control and muscle activity of the gluteus medius and musculus erector spinae in a single-leg stance before and after hip muscle abductor fatigue. [Subjects] Subjects were 22 healthy male adults (mean age; 21.4 yrs) with no significant medical history or current medical problems. [Methods] We examined postural control and muscle activity in a single-leg standing position before and after hip muscle abductor fatigue. A statistical analysis was performed using the paired t-test before and after muscle fatigue, and Pearson's rank correlation coefficient was obtained for muscle activity associated with postural control. [Results] The results indicate a significant increase in stability indices, a decrease in gluteus medius muscle activity, and an increase in right musculus erector spinae activity after fatigue. There was a positive correlation between the increase in right musculus erector spinae activity and increase in postural control. [Conclusion] We believe that postural control increased in the orientation related to the working of the muscles due to their fatigue, and that muscle activity increased to compensate.