Mediation Effect of Pain on the Relationship between Kinesiophobia and Postural Control: Comparison and Correlations in Individuals with Fibromyalgia Syndrome and Asymptomatic Individuals—A Cross-Sectional Study

Background: Individuals with fibromyalgia syndrome (FM) usually present with a fear of movement (kinesiophobia), which causes their symptoms to be maintained and exacerbated. Kinesiophobia can significantly impact postural control; ascertaining their association is crucial in evaluating and managing individuals with FM. This study aims to (1) compare postural control between individuals with FM and asymptomatic individuals, (2) estimate the relationship between kinesiophobia and postural control in individuals with FM, and (3) evaluate whether pain intensity mediates the association between kinesiophobia and postural control in individuals with FM. Methods: This study enrolled 92 individuals (mean age: 51.52 ± 7.7 years) diagnosed with FM and 106 asymptomatic individuals (mean age: 50.47 ± 6.6 years). The examiners estimated the fear of movement and the intensity of pain utilizing the Tampa scale of kinesiophobia (TSK) scores and the visual analogue scale (VAS), respectively. The postural control variables included anteroposterior (A-P) sway in mm, medio-lateral (M-L) sway in mm, and ellipse area in mm(2). Results: The individuals with FM had impaired postural control compared to the asymptomatic individuals (p < 0.001). Kinesiophobia exhibited mild-to-moderate correlations with the postural control variables (nondominant side: A-P sway: r = 0.48, M-L sway: r = 0.49, ellipse area: r = 0.43. Dominant side: A-P sway: r = 0.41, M-L sway: r = 0.33, ellipse area: r = 0.44). The pain intensity significantly mediated the relationship between kinesiophobia and postural control (p < 0.001). Conclusion: Kinesiophobia showed a significant positive relationship with postural control. The individuals with FM with higher TSK scores had decreased postural control. Pain intensity mediated the relationship between kinesiophobia and postural control. These factors must be considered when evaluating and formulating treatment strategies for people with FM.