Background: Different spinal postures may influence inherent tension that is placed upon the peripheral nervous system. Changes in neural tension are believed to directly influence nerve movement. It has been established, using ultrasound imaging, that different spinal postures influence the amount of median and ulnar nerve excursion during neural mobilisation exercises. However, the influence of seated spinal postures upon lower limb nerve movement during neural mobilisation exercises is yet to be explored. Neural mobilisation exercises have been advocated to influence, amongst several mechanisms, movement of peripheral nerves against their mechanical interface. Given that many neural mobilisation exercises that target the lumbar nerve roots, sciatic nerve and associated tracts are often performed in sitting, an understanding of the influence on spinal posture upon sciatic nerve movement will be important for the design of neural mobilisation exercises.