Comparison of surface electromyographic activity of erector spinae before and after the application of central posteroanterior mobilisation on the lumbar spine.

Lumbar spine accessory movements, used by therapists in the treatment of patients with low back pain, is thought to decrease paravertebral muscular activity; however there is little research to support this suggestion. This study investigated the effects of lumbar spine accessory movements on surface electromyography (sEMG) activity of erector spinae. A condition randomised, placebo controlled, repeated measures design was used. sEMG measurements were recorded from 36 asymptomatic subjects following a control, placebo and central posteroanterior (PA) mobilisation to L3 each for 2min. The therapist stood on a force platform while applying the PA mobilisation to quantify the force used. The PA mobilisation applied to each subject had a mean maximum force of 103.3N, mean amplitude of force oscillation of 41.1N, and a frequency of 1.2Hz. Surface electromyographic data were recorded from the musculature adjacent to L3, L5 and T10. There were statistically significant reductions of 15.5% (95% CI: 8.0-22.5%) and 17.8% (95% CI: 12.9-22.4%) in mean sEMG values following mobilisation compared with the control and placebo, respectively. This study demonstrates that a central PA mobilisation to L3 results in a statistically significant decrease in the sEMG activity of erector spinae of an asymptomatic population.