Surface EMG activity of the back musculature during axial spinal unloading using an LTX 3000™ lumbar rehabilitation system

Electromyographic (EMG) analysis has been used successfully to identify back muscle impairment in patients with low back pain. EMG signals from normal subjects during axial spinal unloading using an LTX 3000™ device were obtained and spectral parameters of the electromyographic (EMG) signal were analyzed. The purpose of the study was to determine the optimal time for effective traction using the LTX 3000™ rehabilitation device. These data will serve as a baseline for future studies to help assess back muscle function in low back patients undergoing rehabilitation. Three time points during axial spinal unloading were compared to pre-unloading to detect alterations in median power frequency (MPF), root-mean-square (RMS) and rectified integrated EMG (riEMG) during axial spinal unloading. There were reductions of riRMG during 0-10 minutes of axial spinal unloading in all muscle groups, followed by an increase in riEMG value from 10 to 15 minutes. A similar trend was seen in the RMS values. The MPF did not change during the course of unloading, indicating that there was likely no change in fatigue properties of the paraspinal muscles during axial spinal unloading. The optimal time for effective axial spinal unloading on the basis of muscle was determined to be 10 minutes of axial spinal unloading, and a back assessment procedure was presented that uses surface EMG electrodes to objectively characterize muscle activity and relative fatigue properties. Future studies will use this methodology to assess treatment outcome in a chronic low back pain population.