The Influence of Spine Position on Measures of Lower Extremity Neural Sensitivity

The Slump Test, introduced by Maitland in 1978, has been a clinical staple for determining adverse neural tension or altered neurodynamics and neurosensitivity related to intradiscal derangement or stenotic narrowing of the lumbar spine. The slump test is a highly reliable, common clinical tool used to assess neural tissue mechanosensitivity in patients with both spinal and lower limb pain. However, it is unclear if the slump test can be used to differentiate between those with true adverse neural tension compared to those with neurosensitivity due to compression of the neuroforaminal interface. The positioning of the slump test places maximal tension on the neural tissues both caudally and cranially, either reducing knee extension angle (KEA) in the affected side as opposed to the unaffected side, provoking radicular symptoms, or both. Hall's research found that there was mechanical activity in the hamstring muscles that came on with neural tension testing. This finding can be used to objectively assess when a participant is at their peak tolerable limit of neural tension in specific trunk positions during the slump test. Observation and clinical experience suggest there may be a subset of individuals who have increased neural tension in the slump test during spinal extension (shortening of the nerves) as opposed to flexion (stretch of the nerves). To date, there has been little research that has objectively demonstrated how trunk position affects neural tension during the slump test. Our research aims to determine if there is a difference in patient reported symptoms and hamstring activity between trunk flexion and extension during the slump test with healthy, younger individuals with no recent history of low back pain (LBP) or related symptoms. We expect to find a difference in range of motion (ROM), symptoms, and hamstring activity when the slump test is done in spinal flexion as opposed to spinal extension. This research will help to establish the prevalence of greater sensitivity in the extended vs flexed posture and establish a normative set of symptoms as described by healthy individuals.