Effect of Trunk Extensor Muscle Fatigue on Postural Stability in Healthy Young Adults

Objective To determine the effect of trunk extensor muscle fatigue on postural stability in healthy young adults using clinical measures Design Prospective, experimental, within subject, repeated measures design Setting Tertiary care hospital and research centre Participants 70 healthy adults in the age group of 20 to 25 years, volunteer sample Intervention Fatigue of trunk extensor muscles was induced by repeated dynamic contractions performed to maximum exhaustion. Postural stability was assessed under three different conditions viz. No fatigue, Fatigue and Recovery. Main Outcome Measures One-leg standing balance test and Functional reach test were used to assess static and dynamic postural stability respectively. Results Wilcoxon matched- paired signed ranked test was used for comparison of postural stability in No fatigue and Fatigue condition with p-value less than.001. One-leg standing balance test showed a significant decrease from No fatigue (15.16 + 8.47 seconds) to Fatigue (5.89 + 5.7 seconds) condition. Functional reach test values showed a significant decrease from No fatigue condition (12.34 + 2.61 inches) to Fatigue condition (12.27 + 2.6 inches). Mean recovery time was 12.5+ 3.27 minutes for One-leg standing balance test and 11.93 + 3.22 minutes for the Functional reach test. Further analysis using Mann Whitney test showed no significant difference (P =.288) between the recovery time of one-leg standing balance test and functional reach test. Conclusions Trunk extensor fatigue significantly affects static and dynamic postural stability in healthy young adults. Complete recovery takes 12.5+ 3.27 minutes for static and 11.93 + 3.22 minutes for dynamic postural stability. Results of this study stress the importance of intact trunk extensor muscle function on the regulation of static and dynamic postural stability in healthy young adults. However, more studies are required to determine the effect of trunk extensor muscle fatigue using other clinical measures and in individuals with neuromuscular disorders.