Neuromuscular contributions to balance: investigating upper extremity activation and fall risk in young adults using the Y-Balance Test

Introduction: Falls are a significant cause of injury and mortality in older adults, incurring substantial healthcare costs. Despite this, balance, a key factor in fall prevention, often receives less attention than other health components. This study investigates fall risk in apparently healthy young adults, a relatively understudied population. We hypothesize that early signs of balance impairment can be detected in this group, supporting the need for proactive fall prevention strategies in younger populations. Purpose: To evaluate fall risk in two groups of young, apparently healthy, college-aged students (trained and untrained), we combined imaging electromyography (iEMG) with strenuous balance assessments to measure neuromuscular function and balance performance. Methods: Thirty participants (15 male, 15 female) underwent balance testing (Y-Balance Test) with simultaneous EMG recording of key muscles (deltoid, gastrocnemius, biceps femoris). Correlations between EMG activity and balance performance were assessed using Pearson correlations to identify neuromuscular predictors of fall risk. ANOVAs were used to determine balance differences between groups. Preliminary Results: A one-way ANOVA was conducted to examine the effect of reach direction (anterior, posterolateral, and posteromedial) on deltoid activation during a Y-Balance Test. Results showed no significant differences in either contralateral (F = 0.57, p = 0.57) or ipsilateral (F = 0.37, p = 0.69) deltoid activation across reach directions, indicating that reach direction did not significantly influence activation in this task. Additionally, a one-way ANOVA on the absolute differences between ipsilateral and contralateral posterior deltoid EMG% across reach directions revealed no significant effect (F = 0.50, p = 0.61), further supporting that reach direction did not impact deltoid activation patterns. Conclusion: Reach direction does not significantly influence deltoid activation during the Y-Balance Test in young, healthy adults, suggesting that other neuromuscular factors or muscle groups may be more relevant in assessing balance and fall risk in this population. Further assessment and comparison of EMG in different muscle groups during YBT will be conducted. TUN Human Performance Laboratory This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.