Functional correlates in the rehabilitation of occupational low back pain

The aim of this preliminary report was to identify physiological parameters related to functional improvement in industrial workers with occupational low back pain (LBP) undergoing an intensive rehabilitation program. Four able-bodied and four LBP industrial workers were evaluated before and after a 4-week rehabilitation program. Dynamic and static strength tests, namely sustained isometric contractions, were performed in conjunction with surface electromyographic (EMG) measurements. Significant pre-rehabilitation differences were found between the two groups. Measured forces changed significantly in LBP subjects immediately after rehabilitation. No significative changes were found in the control subjects after the rehabilitation program. After rehabilitation, the slope of decay of the median frequency of the EMG power spectrum at L4 level, during a 60-sec isometric submaximal (60% MVC) contraction, decreased significantly (p < 0.02) indicating a lower fatigue level.