An investigation into the effects of applying a lumbar Maitland mobilisation at different frequencies on sympathetic nervous system activity levels in the lower limb. 
Oscillatory Maitland mobilisations are commonly used in the management of lower back pain with research suggesting that mobilisations at 2 Hz may excite the sympathetic nervous system (SNS) more than sustained pressure glides or 0.5 Hz oscillatory mobilisations.  Investigate the effects of increasing the oscillation frequency greater than 2 Hz.  A double-blind, placebo-controlled, independent group experimental design.  Sixty healthy male volunteers were randomly allocated to one of four groups; a control group (no contact), placebo group (sustained static pressure to L4 vertebra), and two intervention groups receiving a centrally applied postero-anterior mobilisation applied at either 2 Hz or 3 Hz for three 1-min periods.  SNS activity was recorded by a blinded data collector by continuous skin conductance (SC) activity levels in the feet using a Biopac MP35 electrodermal amplifier.  Participants were blinded to their group allocation which was further validated by a post-experiment questionnaire (p > 0.05).  The magnitude of sympathoexcitatory response was greatest for the 3 Hz mobilisation (20%) compared with the 2 Hz mobilisation (12%), placebo (-1%) and control conditions (3%).  Only the 3 Hz group demonstrated statistical significance when compared to placebo intervention (p = 0.002), and the control group (p = 0.02).  SC changes reflect those of previous studies using lumbar mobilisations at 2 Hz, however the 3 Hz group was found to have a greater magnitude of effect worthy of consideration within research and clinical settings.  These findings provide preliminary evidence to support the use of 3 Hz oscillatory mobilisations to affect a greater magnitude of SNS activity than those previously reported (0.5, 1.5 and 2 Hz).