Relationships between neuromuscular functioning, disability and pain in fibromyalgia.

PURPOSE: Fibromyalgia (FM) is associated with pain and alterations in neuromuscular properties and function. A common belief is that these neuromuscular changes are a major cause of limitations in activities or restrictions in participation. The paper aims at examining the basis for such an understanding. Another aim is to investigate how pain is modified or is a modifier of neuromuscular properties and functions.
METHOD: Based on a simplified model to analyze the relationship between pain, neuromuscular properties and function, and activities/participation.
RESULTS: It is argued that the changes in neuromuscular properties and functions seen in FM may simply be an adaptation to lowered physical activity level, rather than being a primary feature of the FM. Furthermore, it is shown that chronic pain and acute contraction-induced pain relates differently to functioning.
CONCLUSION: The analyses indicates that in clinical work and research it is important to distinguish between chronic pain and pain induced by physical activity. Furthermore, the deviations reported for FM in muscular properties and functions such as endurance and strength, are probably not reflecting pathology. Hence, physical activity and improvement of muscular functions are hardly sufficient as treatment of FM.