Objectives: Research has established that the amount of inherent tension a peripheral nerve tract is
exposed to influences nerve excursion and joint range of movement (ROM). The effect that spinal posture
has on sciatic nerve excursion during neural mobilisation exercises has yet to be determined. The purpose
of this research was to examine the influence of different sitting positions (slump-sitting versus upright-sitting)
on the amount of longitudinal sciatic nerve movement during different neural mobilisation exercises
commonly used in clinical practice.
Methods:High-resolution ultrasound imaging followed by frame-by-frame cross-correlation analysis was
used to assess sciatic nerve excursion. Thirty-four healthy participants each performed three different
neural mobilisation exercises in slump-sitting and upright-sitting. Means comparisons were used to
examine the influence of sitting position on sciatic nerve excursion for the three mobilisation exercises.
Linear regression analysis was used to determine whether any of the demographic data represented
predictive variables for longitudinal sciatic nerve excursion.
Results: There was no significant difference in sciatic nerve excursion (across all neural mobilisation
exercises) observed between upright-sitting and slump-sitting positions (P50.26). Although greater
body mass index, greater knee ROM and younger age were associated with higher levels of sciatic
nerve excursion, this model of variables offered weak predictability (R 2
50.22).
Discussion: Following this study, there is no evidence that, in healthy people, longitudinal sciatic nerve
excursion differs significantly with regards to the spinal posture (slump-sitting and upright-sitting). Furthermore,
although some demographic variables are weak predictors, the high variance suggests that there
are other unknown variables that may predict sciatic nerve excursion. It can be inferred from this research
that clinicians can individualise the design of seated neural mobilisation exercises, using different seated
positions, based upon patient comfort and minimisation of neural mechanosensitivity with the knowledge
that sciatic nerve excursion will not be significantly influenced.
