(296) Exercise-Induced Hypoalgesia in Fibromyalgia: An Anomaly of Clinical and Experimental Pain Assessment

Abstract

The purpose of this study was to determine the relation between the acute change in experimental and self-reported pain after isometric and dynamic submaximal resistance exercise in people with fibromyalgia. Thirty-four participants (52.5±11.9 yr, BMI:31.1±6.1; 32 women) with fibromyalgia completed one familiarization session and two randomized exercise sessions (isometric or dynamic) of the right elbow flexors matched for time, intensity, and duty cycle. Experimental pain was quantified via pressure pain thresholds (PPTs) at the right biceps brachii and quadriceps muscles and mechanical temporal summation (TS) at the index finger before and after exercise. Self-reported pain intensity (0-10 visual analog scale) of the exercising arm and whole-body were collected before and immediately after exercise. PPTs did not change following either exercise type. TS decreased following isometric (p=0.042), but not dynamic exercise (p>0.05). Self-reported arm (p 0.05). Similarly, the change in TS after isometric exercise did not correlate with the change in self-reported whole-body pain (p>0.05). Despite a decrease in temporal summation following isometric exercise, people with fibromyalgia report an increase in local and systemic pain following both exercise types. This indicates differential effects of an exercise bout on clinical and experimental pain measures. Further research is required to determine the clinical utility of experimental pain assessments on the acute exercise response in people with fibromyalgia. This research was supported by a Promotion of Doctoral Studies I Scholarship from the Foundation for Physical Therapy and the NICHD (R15HD090265).