Paraspinal muscle deoxygenation and neuromuscular involvement of agonist and antagonist muscles during prolonged trunk extension exercise

Objective: To investigate the agonist and antagonist muscles implication during a prolonged trunk extension exercise and to determine the relationship with paraspinal muscle metabolic and hemodynamic responses in healthy individuals. Methods: Sixteen young and healthy subjects performed a 5-minute exercise of trunk extension. During the exercise, the paraspinal muscle deoxygenation was assessed using near infrared spectroscopy. Electromyography was used to assess the neuromuscular function of paraspinal muscles, biceps femoris, gastrocnemii and rectus abdominis. Results: There were increases in paraspinal muscle deoxygenation ( P < 0.001). There was solely a non-significant trend concerning the increase in electromyographic signals amplitude in paraspinal muscle ( P > 0.05), whereas it decreased in biceps femoris ( P = 0.001) and in the left gastrocnemius (P = 0.002), and it increased in rectus abdominis ( P = 0.023). Electromyographic signals amplitude in paraspinal muscle, biceps femoris and gastrocnemii were correlated with paraspinal muscles deoxygenation ( P < 0.001). Conclusion: The correlations imply that the greater local deoxygenation was; the greater the agonist and co-agonist muscles were involved. Also, the biceps femoris, the gastrocnemii and the rectus abdominis presented neuromuscular fatigue manifestations. This suggests that these agonist and antagonist muscles to trunk extension were significantly involved. This should be considered for the prevention of lower back muscle fatigue and to prevent injuries.