Lack of association between fibromyalgia syndrome and abnormalities in muscle energy metabolism

Abstract

Objective. To compare parameters of muscle energy metabolism in patients with fibromyalgia syndrome (FMS) and sedentary controls.Methods. Thirteen female FMS patients and 13 female sedentary controls underwent a standardized clinical assessment (including dolorimeter measurements of the upper trapezius and tibialis anterior muscles) and a standardized aerobic fitness test including measurement of maximum oxygen uptake (VOzmax). Phosphorus (3'P) magnetic resonance spectroscopy studies of the upper trapezius and tibialis anterior muscles were then performed in FMS patients and controls, at rest and during and following a musclefatiguing exercise protocol.Results. FMS patients and controls had similar levels of VOZmax and of maximum voluntary contraction (MVC) of the upper trapezius and tibialis anterior muscles. After controlling for VOZmax and MVC, measurements of phosphocreatine (PCr), inorganic phosphate (Pi), and intracellular pH in these muscles were not significantly different in FMS patients versus sedentary controls either at rest, during exercise, or during recovery. In the patients with FMS, no correlation was Submitted for publication May 25, 1993; accepted in revised form October 19, 1993. found between overall or local pain severity and the principal muscle metabolic parameter, PCr/Pi. Inverse correlations between dolorimeter scores at 2 muscle sites and tibialis anterior PCr/P, were found both in patients and in controls.Conclusion. This study demonstrates that under the conditions studied, muscle energy metabolism in FMS is no different than that in sedentary controls.These findings do not support the hypothesis that detectable defects in muscle energy metabolism occur in FMS.Fibromyalgia syndrome (FMS) is a common chronic musculoskeletal pain syndrome which has been recently defined in a multicenter study (l), although its cause remains unknown (2). A number of studies using invasive and noninvasive techniques have suggested that patients with FMS have abnormalities in muscle energy metabolism (3-8). Several histologic studies appeared to demonstrate histopathologic changes consistent with tissue anoxia, including "moth-eaten" and "ragged-red' ' muscle fibers at the sites of tenderness (4-6). More recent studies appeared to confirm these findings, with the demonstration of local hypoxia and reduced high-energy phosphate levels at sites of tenderness, compared with normal controls (7,8). It has also been recently recognized, however, that patients with FMS are relatively deconditioned when compared with normal subjects (9). Furthermore, increases in high-energy phosphate levels in skeletal muscle may occur in response to physical training (10). It is therefore possible that studies demonstrating lower levels of high-energy phosphate compounds in muscles of FMS patients compared with normal controls reflect only a disuse effect. Nevertheless, no studies of muscle metabolism in FMS to date have taken into account the level of deconditioning in study subjects.

Acute heavy‐resistance exercise–induced pain and neuromuscular fatigue in elderly women with fibromyalgia and in healthy controls: Effects of strength training

“…It is possible that the elderly subjects may not be able to fully activate their muscles during the initial sets of maximal loading (7), as also indicated by the slightly increased EMGs during the first 2 sets (Figure 1). Our results are consistent with findings of earlier studies that measured acute muscle fatigue with various dynamic or isometric muscle fatiguing protocols (7,8). Further, we showed that the patients' blood lactate concentration responses were comparable with those of healthy controls.…”

“…Increased (6) and similar (7) exercise-induced pain has been reported in patients compared with healthy controls. Studies have also shown that middleaged patients have normal physiologic muscle fatigue responses measured by various fatiguing protocols (7,8).…”

“…A single training session should cause some acute fatigue, which, in turn, leads to adaptation of the neuromuscular system during regular training. Acute muscle fatigue in patients with FM has been tested using different protocols (7,8), but to date only 1 study (7) has examined acute neuromuscular fatigue and DOMS in middle-aged patients with FM, using a loading session typically applied in strength training. The purposes of the present study were 1) to examine acute fatigue of the neuromuscular system, blood lactate concentration, and DOMS in elderly women with FM and healthy women during and subsequent to a heavy-resistance fatiguing loading protocol and 2) to study whether the responses to acute fatiguing loading change after the 21-week strength training period and differ between women with FM and healthy women.…”

Use of P-31 magnetic resonance spectroscopy to detect metabolic abnormalities in muscles of patients with fibromyalgia

“…Thus, we have acquired additional parameters for confirming the detection of abnormalities in FMS. We do not in any way contest the results reported by the other investigators (15)(16)(17)(18)(19) but rather we believe that the data are accurate and valid for the particular experimental conditions used.…”

Effectiveness of physical activity in reducing pain in patients with fibromyalgia: a blinded randomized clinical trial

“…No statistically signiWcant diVerences in pain relief were found between the WA and MS groups, which is consistent with the Wndings of other studies [15,17], although there was a non-signiWcant trend toward pain improvement in the MS group between weeks 8 and 16. These Wndings indicate that the improvement in Wbromyalgia symptoms due to exercises was probably related to the combat of eVects of deconditioning [29].…”