Validity and Reliability of The Single-Item Kinesiophobia Scale in Persons with Neck and Back Pain

Purpose: Kinesiophobia is a significant concern in persons with neck and back pain. This study aimed to evaluate the measurement properties of the Single-Item Kinesiophobia Scale (SKS) including test-retest reliability and convergent validity. Material and Methods: A total of 101 participants (n=38 with neck pain and n=63 with back pain) were included. The SKS was applied twice 7-14 days apart. Test-retest reliability was assessed using intraclass correlation coefficients (ICCs). Validity was examined through correlations with established measures: the Tampa Scale for Kinesiophobia (TKS), Visual Analog Scale (VAS) during activity and rest, Neck Disability Index (NDI), and Oswestry Disability Index (ODI). Floor/ceiling effects and score distribution were also analyzed. Results: The SKS demonstrated moderate test-retest reliability [neck pain: ICC=0.56 (95%CI: 0.30–0.75), back pain: 0.52 (95%CI: 0.31–0.68)] in the back pain group. It demonstrated moderate correlations with the TKS (rho=0.446-0.555) but small correlations with the VAS (rho=0.261–0.265) and ODI (rho=0.278) in the back pain group. No significant correlations were found between the SKS and VAS or NDI in the neck pain group. Conclusion: The SKS is a simple and feasible screening tool for kinesiophobia but should be used alongside comprehensive measures due to its moderate psychometric properties and limitations.