Short-term changes in median nerve neural tension after a suboccipital muscle inhibition technique in subjects with cervical whiplash: a randomised controlled trial

Objectives To assess the immediate effect of a suboccipital muscle inhibition (SMI) technique on: (a) neck pain, (b) elbow extension range of motion during the upper limb neurodynamic test of the median nerve (ULNT-1), and (c) grip strength in subjects with cervical whiplash; and determine the relationships between key variables. Design Randomised, single-blind, controlled clinical trial. Setting Faculty of Nursing, Physiotherapy and Podiatry, University of Seville, Spain. Participants Forty subjects {mean age 34 years [standard deviation (SD) 3.6]} with Grade I or II cervical whiplash and a positive response to the ULNT-1 were recruited and distributed into two study groups: intervention group (IG) (n=20) and control group (CG) (n=20). Interventions The IG underwent the SMI technique for 4 minutes and the CG received a sham (placebo) intervention. Measures were collected immediately after the intervention. Main outcome measures The primary outcome was elbow range of motion during the ULNT-1, measured with a goniometer. The secondary outcomes were self-perceived neck pain (visual analogue scale) and free-pain grip strength, measured with a digital dynamometer. Results The mean baseline elbow range of motion was 116.0 degrees (SD 10.2) for the CG and 130.1 degrees (SD 7.8) for the IG. The within-group comparison found a significant difference in elbow range of motion for the IG [mean difference -15.4 degrees, 95% confidence interval (CI) -20.1 to -10.6; P = 0.01], but not for the CG (mean difference -4.9 degrees, 95% CI -11.8 to 2.0; P = 0.15). In the between-group comparison, the difference in elbow range of motion was significant (mean difference -10.5 degrees, 95% CI -18.6 to -2.3; P = 0.013), but the differences in grip strength (P = 0.06) and neck pain (P = 0.38) were not significant. Conclusion The SMI technique has an immediate positive effect on elbow extension in the ULNT-1. No immediate effects on self-perceived cervical pain or grip strength were observed. (C) 2013 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.