Razi Journal of Medical Sciences

Background: Falls is due to people's failure of balance recovery. The purpose of this study was to investigate the effect of trunk extensor muscle fatigue on static balance control in young healthy adults compared to middle aged participants.

Methods: Ten young adult females (23 ± 1.6 years) and 6 middle-aged females (51 ± 5.4 years) participated in stand immobile test on a force plate, with their feet together and eyes closed under two conditions before and after fatigue. Fatigue was achieved through repetitive extensions of the trunk until a subjective fatigue level was reached. We measured center of pressure (COP) displacements in the A/P and M/L directions using a force plate to assess static balance.

Results: We did not observe any significant interaction between age and fatigue. The COP variability was higher for the middle aged compared to the young adults in both the fatigue and no-fatigue conditions.

Conclusion: The results of this study indicate that trunk extensor fatigue does not affect static balance differently for young compared to middle aged subjects. This study also suggests that postural control decreases significantly with increasing age. Trunk extensor fatigue did not significantly affect the balance control of upright stance.