Electromyographic Analysis Of Multifidus Muscle Activity During Three Exercises

The multifidus muscle is integral to spinal stability and posture control. To enhance rehabilitation and training programs, it is essential to understand the patterns of its activation across various exercises. PURPOSE: The purpose of this study was to analyze the electromyographic (EMG) activity of the multifidus muscle during three specific exercises: deadlifts, bird-dogs, and single-leg balance exercises, to determine which exercise most effectively activates this muscle. METHODOLOGY: Twenty adults (men: 9; women: 11; age: 24.7 + 2.1 yr; height: 167.9 + 10.8 cm; weight: 73.9 + 15.8 kg (mean + SD)) participated in the study. Surface EMG electrodes were placed bilaterally at the L4-L5 level after skin preparation. Deadlifts (5 reps at 50% body weight), bird-dog held for 10 sec on each side while holding a 2.27 kg weight in the outstretched hand, and single-leg stance held for 10 sec on each foot were performed under supervision in a randomized order. EMG data (max amplitude) were recorded with each session lasting ~15 minutes. Data were analyzed to compare muscle activation patterns across exercises. RESULTS: EMG activity showed significant (p < 0.05) differences across exercises with deadlifts inducing the highest mean muscle activation (0.949 + 0.623 mV), followed by bird-dog right (0.370 + 0.173 mV) and bird-dog left (0.352 + 0.161 mV). The single-leg balance exercises elicited the lowest mean muscle activations, both for the right (0.124 + 0.049 mV) and left sides (0.134 + 0.068 mV). There were no bilateral differences for any of the exercises. CONCLUSION: The multifidus muscle showed varying levels of activation across different exercises, with the highest activation during deadlifts and the lowest during single-leg balance tasks. The deadlifts elicited a significantly stronger muscle response compared to balance exercises, suggesting that weight-bearing exercises might be more effective for multifidus muscle activation. The findings suggest that rehabilitation programs that include deadlifts could potentially offer greater benefits for improving core stability and reducing back pain.