METHODS: A total of 130 women with FM (age 22-64 years) were included in this assessor-blinded randomized controlled multicenter trial examining the effects of person-centered progressive resistance exercise compared with an active control group. The intervention was performed twice a week for 15 weeks. Outcomes were five dimensions of fatigue measured with the Multidimensional Fatigue Inventory (MFI-20). Information about background was collected and the women also completed several health-related questionnaires. Multiple linear stepwise regression was used to analyze predictors of change in fatigue in the total population.
RESULTS: A higher improvement was found at the post-treatment examination for change in the resistance exercise group, as compared to change in the active control group in the MFI-20 subscale of physical fatigue (resistance group Δ -1.7, SD 4.3, controls Δ 0.0, SD 2.7, p = 0.013), with an effect size of 0.33. Sleep efficiency was the strongest predictor of change in the MFI-20 subscale general fatigue (beta = -0.54, p = 0.031, R (2) = 0.05). Participating in resistance exercise (beta = 1.90, p = 0.010) and working fewer hours per week (beta = 0.84, p = 0.005) were independent significant predictors of change in physical fatigue (R (2) = 0.14).
CONCLUSIONS: Person-centered progressive resistance exercise improved physical fatigue in women with FM when compared to an active control group.
TRIAL REGISTRATION: ClinicalTrials.gov NCT01226784 . Registered 21 October 2010.