A preliminary investigation into the magnitude of effect of lumbar extension exercises and a segmental rotatory manipulation on sympathetic nervous system activity.

Two commonly utilised manual therapy techniques; McKenzie's lumbar extension exercises (EE); and segmental rotational grade V manipulation were investigated to determine their magnitude of neurophysiological effect. Proxy measures of sympathetic nervous system (SNS) activity (skin conductance) were utilised to ascertaining neurophysiological response. This study determined the neurological effects of these two treatment techniques in addition to establishing the Biopac System as a reliable measure of neurophysiological changes. A quasi-experimental, independent group's design was utilised, with random allocation of 50 normal, healthy participants into a manipulation or an EE group. Neurophysiological measurements of skin conductance were taken in the lower limbs before, during and after the administration of the techniques. Results were converted into percentage change calculations for the intervention and the post-intervention periods. Both treatments increased SNS activity during the intervention period, 63% for the manipulation group (p = 0.0005) and 42% for EE group (p = 0.0005) with the manipulative technique having significantly greater effect (p = 0.012). Further analysis of the manipulation group found no difference between the 'opening' and the 'closing' side of the technique (p = 0.76). Biopac System is a reliable method for measuring SNS activity with minimum measurement variability. Preliminary evidence now exists supporting the neurophysiological effects of two lumbar techniques.