Abstract
OBJECTIVES To compare the activation pattern of the trunk antagonistic muscles and also the myoelectric manifestations of muscle fatigue between subjects with and without recurrent non-specific low back pain, during the fatigue provocation of the erector spinae. METHODS The study involved 19 subjects with recurrent low back pain with a non-specific cause (seven men, 12 women, 38.53 ± 8.12 years, 68.35 ± 18.12 kg, 1.66 ± 0.09 m), and 19 healthy subjects (seven men, 12 women, 40.42 ± 8.63 years, 69.57 ± 12.76 kg, 1.64 ± 0.07 m). The electromyographic signal of the internal oblique, lumbar multifidus, rectus abdominis and lumbar iliocostalis muscles, bilateral, were collected during Biering-Sorensen test execution. RESULTS The group with low back pain showed a lower co-contraction rate of the internal oblique/lumbar multifidus (p = 0.006) and lower activation amplitude of the internal oblique (p = 0.019), both on the right side when compared to the group without low back pain. No differences were observed between the groups for muscle fatigue indicators (p > 0.05). CONCLUSION When the erector spine muscle fatigue occurs - even when the groups were similar as to the ability of extensors muscles to resist fatigue - differences were found between subjects with and without low back pain regarding the recruitment pattern of the task antagonist muscle, because subjects with low back pain showed lesser activation and co-contraction in relation to the healthy group.
Highlights
Intervertebral stabilization is led by three interdependent subsystems: muscular or active, articular or passive and neural[1,2]
Significant differences were found between groups for the variables: internal oblique (IO) normalized root mean square (RMS) (p = 0.019) (Figure 3) and IO/ MU co-contraction rate (p = 0.006) (Figure 4), both on the right side, where control group (CG) had higher mean values compared to experimental group (EG)
Despite the premise that the erector spinae of subjects with low back pain are more susceptible to fatigue compared to healthy subjects[13,14], some authors[15,21,22] that used similar methodology applied in our study found no differences between groups with and without low back pain for the median frequency (MF) analysis
Summary
Intervertebral stabilization is led by three interdependent subsystems: muscular or active, articular or passive and neural[1,2]. Previous studies of the neuromuscular activation pattern found greater co-contraction of the flexor and extensor lumbar muscles[7,8,9], and greater trunk stiffness coefficient[10] in people with low back pain when performing different tasks, as compared to healthy subjects. One study observed increases in spinal stiffness and trunk muscle activation when low back pain is elicited in healthy subjects and provided empirical evidence about the mediation of muscle activity in the spinal stiffness modification[11]. This adaptive strategy aims to restrict the range of trunk movement to avoid worsening or onset of pain and other injuries[1,9,12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
