Received: 23 Oct, 2012 Accepted: 21 Dec, 2012

  Background & Aims : The objective of this study was to investigate the effects of chronic non specific neck pain on shoulder girdle muscles activation pattern.

  Materials & Methods: Temporal & intensity of shoulder muscles activation characteristics during a scapular plane elevation were evaluated in two groups with & without chronic nonspecific neck pain: one group contains 20 subjects with chronic neck pain and the other group contains 20 healthy subjects which matched on age , sex and dominant limb with the subject on the patients group.

  Surface electromyographic activity of four muscles (Anterior & Middle deltoid, upper & lower Trapezius) recorded at 1500 Hz for 10 seconds whilst each subject performed 3 dynamic elevation movement with a load (%25-30 of her/his maximum voluntary exertion).

  Results: With MANOVA results revealed that there was no statistical difference between two groups unless onset delays of middle deltoid and peak delay of upper trapezius. But the differences between two groups was discussable, because the onset delay and peak delay of all muscles in patient group increased and peak amplitude of dynamic elevation (Normalized with maximum amplitude of Maximum voluntary Exertion test) decreased relative to healthy group.

  Conclusion: In conclusion, chronic non specific neck pain alters the shoulder muscles activation pattern specially the activation pattern of upper trapezius. But with a large sample size these differences will be statistically valuable.

  SOURCE: URMIA MED J 2012: 23(7): 822 ISSN: 1027-3727