The arm curl score is the best indicator of reduced upper extremity exercise capacity in women with fibromyalgia: A cross-sectional study.

Background: Unsupported upper extremity exercise capacity (UUEEC) is crucial for sustaining everyday functions; whether it is compromised in the fibromyalgia (FM) population is unknown.

Objective: The study aimed to assess UUEEC in women with FM and to determine associated factors.

Methods: This is a cross-sectional study. Methods: This study was conducted with 48 women with FM and 48 healthy women between the ages of 18-65. UUEEC, muscle strength, flexibility and disability of upper extremity, disease severity, pain catastrophizing, and quality of life assessed with the Six Minute Pegboard and Ring Test (6PBRT), arm curl test, hand grip strength test, back-scratch test, Disability of Arm, Shoulder, and Hand (DASH), Fibromyalgia Impact Questionnaire (FIQ) and Pain Catastrophizing Scale and Short-form 36 questionnaires, respectively.

Results: The 6PBRT score was significantly decreased in the women with FM compared to healthy women (p < 0.001, Cohen d: 1.28). The multivariate linear regression analysis revealed that the model incorporating the arm curl score, hand grip strength, DASH, and FIQ scores was explained 68% of the variance in 6PBRT score (R2 = 0.672, p < 0.001). The results indicated that all variables in the model were independent predictors of 6PBRT score, with the arm curl score was the strongest predictor (β = 6.36, p = 0.015).

Conclusions: This study suggests that UUEEC measured by 6PBRT is reduced in women with FM, and the upper extremity muscle strength is closely related to the 6PBRT score. Accordingly, strengthening the biceps brachii muscle in women with FM, whose muscle weakness is common, may be effective in improving UUEEC, which is directly associated to daily activities.