Muscle Architecture and Muscle Strength in Fibromyalgia

The goal of this observational study is to determine whether there is decrease in muscle mass and muscle strength in Fibromyalgia Syndrome (FMS) patients in comparison to controls. And to determine whether these parameters are correlated with clinical ones. Briefly the main questions investigators aims to answer are: * Is there a significant difference in muscle morphology between FMS and controls? * Is there a significant difference in muscle strength between FMS and controls? * Is there a relationship between muscle thickness and pennation angle of the Quadriceps, gastrocnemius medialis, gastrocnemius lateralis and Tibialis anterior muscles and disease activity, pain and functionality? * Is there a correlation between muscle strength in FMS and disease activity, pain and functionality?

Fibromyalgia syndrome (FMS) was named by Smythe and Moldofsky when they defined tender points in 1970s. It is defined as chronic, generalized musculoskeletal pain accompanying with fatigue, sleep disturbance , cognitive and somatic disturbance. FMS has variable prevalence as %0,7-11 and usually affects middle aged women. It is second most common rheumatologic disease after osteoarthritis and thought to be the most common reason for musculoskeletal pain in middle aged women. Recent studies have reported that both sarcopenia and decreased muscle strength occur in patients with chronic inflammatory diseases such as rheumatoid arthritis. There are concerns that sarcopenia may affect exercise tolerance, activities of daily living, and ultimately have a negative impact on cardiovascular fitness and physical and emotional well-being. On the other hand there is researches that support inflammation-driven pathways in the pathogenesis of fibromyalgia. Given the risk of pain related reduction in physical activity, patients are expected to have accelerated muscle wasting , decreased muscle strength and endurance and functionality. However, there is no study that focused on muscle architecture and strength in FMS. This led us to design our study which will evaluate patients lower extremity muscles' thickness and pennation angles by ultrasound , most daily used muscles' strength by dynamometer, functionality by timed-up test and try to find whether there is a correlation between these parameters and patients' disease activity which will be determined with FMS specific scales.