Activation of Multifidus and Erector Spinae Muscles during Upper Limb Flexion and Abduction in Patients with Nonspecific Low Back Pain / 中国康复理论与实践

ABSTRACT

Objective:To compare the difference in the onset time of the trunk muscles activity in individuals with and without nonspecific low back pain (NLBP) during upper limb flexion and abduction. Methods:From September to December, 2017, 21 patients with NLBP (NLBP group) and 21 volunteers (control group) participated in this study. Surface electromyography (sEMG) signals were recorded from the anterior deltoid, middle deltoid, multifidus and erector spinae muscles during upper limb flexion and abduction in standing position. Relative differences in the onset times between each muscle and the prime mover were calculated. Results:During upper limb flexion, the right multifidus muscle, bilateral erector spinae were activated in advance of the agonist muscle (anterior deltoid), while the left multifidus muscle was delayed relative to the agonist muscle in both groups. The onset time of the right erector spinae was significantly delayed in NLBP group than in the control group (t = -2.393, P = 0.019). During upper limb abduction, bilateral multifidus muscle and bilateral erector spinae were activated in advance of the agonist muscle (middle deltoid) in the control group. Additionally, in NLBP group, the left erector spinae was activated in advance of the agonist muscle, bilateral multifidus and right erector spinae were delayed relative to the agonist muscle. There was no significant difference in the relative onset time between both groups (t < 1.393, P > 0.05). Conclusion:During upper limb flexion and abduction, the trunk muscles of the lower back are activated in advance for healthy individuals, while individuals with NLBP have a possibly delayed activation of trunk muscles.