Increased incidence of a resonance in the phosphodiester region of ³¹p nuclear magnetic resonance spectra in the skeletal muscle of fibromyalgia patients

Objective. To determine if patients with fibromy algia syndrome (FMS) are more susceptible to activityinduced muscle damage than are healthy subjects. Methods. Eleven FMS patients and 10 healthy subjects performed concentric and eccentric exercise with their dominant and nondominant forearms, respectively. ³¹P magnetic resonance spectroscopy (to assess inorganic phosphate [P_i] and phosphocreatine [PCr]) and dolorimetry (to assess pain) were performed before and 20 minutes after exercise and at 4 subsequent 24‐hour intervals. Results. Neither group exhibited increased P_i/ PCr ratios or reduced dolorimetry scores following the exercise protocols. FMS patients did display a phosphodiester resonance at a higher rate than healthy subjects (37% versus 12%), but this was not related to the exercise. Conclusion. Unchanged P_i/PCr ratios and dolorimetry scores following acute exercise provide evidence against the hypothesis that FMS patients are more susceptible to activity‐induced muscle damage than are healthy subjects, although P_i/PCr and pain may not adequately document such damage. The frequent occurrence of phosphodiester in the spectra of FMS patients may indicate a sarcolemmal abnormality in these subjects.