Can Early Fatigue in Leg Muscles After Exercise Cause Postural Instability in Women With Fibromyalgia?

Objectives: This study aimed to investigate the effects of exercise-induced lower limb muscle fatigue on postural stability in female patients with fibromyalgia (FMS).

Method: This study included 19 female patients diagnosed with FMS according to the 2010 American College of Rheumatology criteria and 19 age-matched healthy controls. Muscle fatigue was induced by chair sit-to-stand (STS) repetitions in all participants. Postural stability was evaluated before and immediately after muscle fatigue test (MFT) in standard bipedal and tandem stances with eyes open (EO) and eyes closed (EC), and in single leg stance with EO using a foot pressure platform.

Results: The mean number of STS repetitions on MFT was lower in FMS patients (p<0.001). Before MFT, plantar center of pressure (CoP) excursions was greater in FMS patients versus controls in all postures tested except in EO bipedal stance (all p<0.01). Postural sway increased post-MFT in both FMS and control groups in all stances (all p<0.001). Post-MFT increase in postural sway was greater in the FMS group versus controls (all p<0.05).

Conclusion: Lower limb muscle fatigue occurs earlier in FMS patients than in healthy individuals and exacerbates postural stability problems. This indicates the importance of planning tailored exercise programs for these patients.