Evaluation of the Immediate Effect of Acupuncture on the Upper Trapezius Muscle in Patients With Nonspecific Neck Pain.

The aim of the proposed study is to evaluate the immediate effect of acupuncture on pain, cervical range of motion and electromyographic activity of the upper trapezius muscle in patients with nonspecific neck pain.Twelve patients with nonspecific neck pain and 12 healthy subjects will be enrolled in a randomized, single-blind, crossover study. Each patient will receive two forms of treatment in random order: a single session of traditional acupuncture and sham acupuncture. To eliminate carry-over treatment effects, a one-week wash-out period will be respected between sessions. Surface electromyography will be used to determine motor control in the upper trapezius muscle before and after treatment. The outcome measures in the group with neck pain will be a numerical pain rating scale (range: 0 [no pain] to 10 [maximum pain]), documentation of the pain area on a body chart and cervical range of motion. Linear regression analysis will be applied for each individual to investigate associations between the sEMG variables and force (excluding the sixth step). The slopes of the regression lines will be used to measure the sensitivity of the sEMG variables regarding changes in force. The Shapiro-Wilk test will be used to test the normality of the data distribution regarding RMS and MDF values in the third and sixth step of the step contraction. Paired samples (Student's t-test or Wilcoxon test) will be used to test differences between third and sixth contraction step. A mixed linear model will be used to analyze and compare the sEMG data during sustained contraction (five steps) between pre-acupuncture (EMG-1) and post-acupuncture (EMG-2) evaluations. These comparisons will demonstrate whether acupoints TE-5 and LI-11 affect the activity of the upper trapezius muscle, as hypothesized. The pain (NRS, PPT and area) and cervical ROM data collected during the four evaluations will also be compared using a mixed linear model. The Statistical Package for Social Sciences (SPSS, version 19.0 for Windows) will be employed for the statistical analysis, with the level of significance set to 5% (p < 0.05).