The Influence of Verbal Suggestion on Post-Needling Soreness and Pain Processing after Dry Needling Treatment: An Experimental Study

Background: It remains unclear as to whether verbal suggestions and expectancies can influence the perception of post-needling soreness. The aim of this study was to analyze the effects of verbal suggestions on post-needling soreness after dry needling of the trapezius muscle. Methods: This study is a randomized controlled trial including healthy subjects randomly assigned to one of three groups receiving different verbal suggestions about the effects of dry needling and the occurrence of post needling soreness (positive, negative, or neutral). Then, dry needling on a latent trigger point of the upper trapezius muscle was performed and the following outcomes were measured immediately after, 24, 48, and 72 h, and one week after the intervention: post-needling soreness intensity, pressure pain threshold (PPT), temporal summation (TS) and conditioned pain modulation (CPM). Results: Seventy-three consecutive participants were screened and 42 participants (12 men and 30 women, aged: 24 ± 8 years old) were eligible and finished the study protocol. The results showed that verbal suggestion did not influence the perception of post-needling soreness, since there were no differences between groups ( p < 0.05) on the intensity of post-needling soreness or tenderness over a one-week follow-up. Moreover, verbal suggestion did not associate with changes in sensorimotor variables of TS and CPM. Conclusions: The induction of different types of expectations through verbal suggestion does not influence the perception of acute pain perceived during the performance of a deep dry needling technique and post-needling pain or soreness after deep dry needling on a latent upper trapezius myofascial trigger point (MTrP).