Psychometric Properties of the Four Square Step Test in Incomplete Spinal Cord Injury

Why clinicians should know about it

• Picked for Rehabilitation (paper of the day, 4 October 2026): FSST validation for dynamic balance in incomplete SCI

Abstract

BACKGROUND: Clinicians require reliable and valid measures to assess dynamic balance and fall risk in individuals with incomplete spinal cord injury (iSCI). Currently, no psychometrically sound measures exist for capturing higher-level balance impairments in this population. The Four Square Step Test (FSST) is a dynamic balance measure assessing a person's ability to step quickly in multiple directions over obstacles. The FSST has been established as reliable and valid for various neurological populations and is particularly suited for individuals who ambulate without assistance. OBJECTIVES: This study aimed to evaluate the validity and interrater reliability of the FSST in an ambulatory, chronic iSCI population. METHODS: We used data from 23 participants to assess FSST convergent validity with established gait and balance measures. We used data from 11 participants, each assessed by multiple raters, to evaluate interrater reliability. RESULTS: Spearman's rank correlations (ρ) revealed strong, significant correlations (all Ps < .01) between the FSST and the Berg Balance Scale (ρ = -0.81), 10-Meter Walk Test self-selected (ρ = -0.77), 10-Meter Walk Test fast (ρ = -0.84), and Timed Up and Go (ρ = 0.81), indicating convergent validity. The intraclass correlation coefficient (ICC) between expert and novice raters was excellent (ICC = 1.0), confirming interrater reliability. CONCLUSION: Overall, the FSST demonstrated excellent reliability and validity, suggesting it is suitable for evaluating dynamic balance in high-functioning individuals with iSCI.

Abstract as published, via PubMed.