Exercise-induced hypoalgesia following proprioceptive neuromuscular facilitation and resistance training among individuals with shoulder myofascial pain: a pilot study

ObjectiveThe present study estimated the effect of proprioceptive neuromuscular facilitation (PNF) and resistance training on exercise-induced hypoalgesia (EIH) and conditioned pain modulation (CPM) among patients with myofascial pain syndrome (MPS). MethodsA total of 76 female MPS patients (aged from 18-30) with a visual analog scale (VAS) score greater than 30/100 mm were enrolled in the study. Participants were randomly assigned into 3 intervention groups, including isometric (n=18), isotonic (n=19) and PNF (n=20) exercises, and 1 control group (n=19) with no intervention. Pressure pain threshold (PPT) and the CPM responses at myofascial trigger point, arm and leg sites were assessed before and after exercise session. ResultsThere was an increase in PPT and CPM responses at trigger point, arm and leg sites in participants performed PNF and isotonic exercise, while the isometric exercise only increased PPT at leg sites. Compared with control group, both isotonic and PNF group showed greater EIH responses at the trigger points. However, only the PNF exercise significantly improved PPT and CPM responses at arm and leg sites compared to the control group. ConclusionsPNF, isotonic and isometric exercises could lead to local and global EIH effect. The increase in CPM response after PNF and isotonic exercises indicated that the EIH mechanisms of different resistance exercises may be attributed to the enhancement of the endogenous pain modulation through the motor-sensory interaction from the additional eccentric and dynamic muscle contraction.