Isometric Exercise and Endogenous Pain Modulation

Fibromyalgia syndrome (FMS) is a chronic pain condition that is characterized by widespread pain which affects 5-8% of the general population. Past research has shown that people with FMS demonstrate enhanced pain facilitation and reduced pain inhibition in the central nervous system. Incorporating a biopsychosocial model of pain may help develop strategies to prevent the functional decline and alleviate the suffering that occurs in this population. Exercise is a mainstay of pain rehabilitation with multiple health benefits, one of which is decreasing pain; a phenomenon known as exercise induced hypoalgesia (EIH). Emerging evidence has shown that exercise decreases pain facilitation in healthy adults and in some individuals with FMS. However, it's unclear whether exercise improves pain inhibition in individuals with FMS. The purpose of this study is to investigate endogenous pain inhibition, measured by conditioned pain modulation (CPM), following isometric exercise of the quadriceps muscle in individuals with FMS. In addition, factors that might affect this response such as physical activity, body composition, and psychosocial issues will be examined. Understanding how exercise impacts pain and the contributing factors will help guide the prescription of exercise to optimize pain rehabilitation.