Decoupling of bilateral paraspinal excitation in subjects with low back pain.

This study compared bilateral paraspinal excitation in normal subjects and subjects with low back pain. Comparison was made between six control subjects and seven low back pain subjects who performed maximum-effort isometric trunk extension in minimum elapsed time at two trunk angles. Electromyographic signals were collected bilaterally from the paraspinal musculature. The time- and amplitude-normalized electromyographic data were analyzed using a repeatability criterion sensitive to temporal and amplitude differences. This analysis showed that low back pain subjects demonstrated temporal and amplitude decoupling of the paraspinal musculature bilaterally. Low back pain subjects also demonstrated clinically meaningful disruptions between paraspinal excitation and isometric trunk extension moment. This method may be useful in quantifying neuromotor control in low back pain for initial and follow-up clinical evaluation for static and dynamic functional tests.