Background: Changes in the motor control of the spine were found in patients with chronic low back pain (CLBP). Sudden loading of the spine is supposed to be the cause of about 12% of lower back injuries. However, some aspects of this problem, such as alterations in the sensory-motor control of the spine, remain questionable.
Objective: To investigate the effects of familiarization with loading, weight and size of loading on neuromuscular responses during sudden upper limb loading in CLBP patients.
Methods: In this quasi-experimental study surface electromyography of the erector spinae (ES) and transverses abdominis/internal oblique (TrA/IO) and external oblique (EOA) muscles were recorded in 7 men and 13 women with CLBP and 20 asymptomatic subjects (10 men and 10 women) aged 18-45 years from the general community familiarization. Moreover, investigating control of the posture measurements of the center of pressure (COP) and vertical ground reaction force (GRF) or Fz were recorded using a force plate. Data were analyzed using paired t-test and independent t-test with the significance level of 0.05.
Results: Data analyses were performed using SPSS version 18. Some electromyography and force plate variables were significantly different for different conditions in each group and between the asymptomatic and low back pain groups (p⩽ 0.05).
Conclusion: Several motor control changes were observed in the CLBP patients. These patients showed decreased trunk muscle activity as well as too early and too delayed responses compared to asymptomatic subjects.
Keywords: Chronic low back pain; posture; surface electromyography.