Investigation of the Effects of a Centrally Applied Lumbar Sustained Natural Apophyseal Glide Mobilization on Lower Limb Sympathetic Nervous System Activity in Asymptomatic Subjects

Objective The purpose of this study was to investigate the effects of a manual mobilization technique on indirect measures of sympathetic nervous system activity. Methods Forty-five healthy volunteers participated in this randomized, single-blinded, parallel-group 3-arm design (experimental, sham [placebo], and control group), comprising 15 subjects each. For the experimental group, lumbar mobilization involving an active movement, the Mulligan sustained natural apophyseal glide (SNAG), was applied on L4 spinous process by an experienced manual therapist. Sustained natural apophyseal glides were performed in sitting with active flexion (6 times × 3 sets). The sham technique simulated the SNAG without applying any force. In the control group, participants were placed in a static sitting position throughout the experiment. Measures of skin conductance in the lower limbs (L4 dermatome) were recorded to reflect sympathetic nervous system activity in the preintervention, periintervention, and postintervention periods. Differences in percentage change of skin conductance were analyzed with analysis of variance and post hoc tests. Results Lumbar SNAG produced sympathoexcitation compared with the control group in the intervention period (P = .04). No significant difference was found between SNAG and sham groups, and no statistically significant difference was found between groups in the final rest period. Conclusion The results of this study showed that, in asymptomatic participants, both lumbar SNAG and sham techniques performed on L4/5 intervertebral joint with active flexion induced a sympathoexcitatory response in lower limbs compared with the control group.