Test–Retest Reliability, Validity, and Clinical Utility of the Modified Figure-of-Eight Balance Test with Tandem Gait in High-Functioning Older Adults

Background and Purpose: Enhancing or maintaining dynamic balance is essential for older adults to mitigate the risk of mobility decline associated with aging and to preserve their ability to engage in socially active and independent lifestyles. The Modified Figure-of-Eight balance test with tandem gait (MFEtan) was specifically designed to challenge mediolateral stability and assess balance control during tasks requiring continuous directional changes, providing a more demanding evaluation for high-functioning older adults. The test yields 2 performance domains: completion time and number of oversteps. This cross-sectional study evaluated the test–retest reliability and validity of the MFEtan test and discussed its implications for clinical utility in high-functioning older adults. Methods: Fifty-two participants (mean age = 69.6 years; SD = 3.8 years; 82.7% female) completed the MFEtan balance and other established balance tests (one-leg stance [OLS], Timed Up and Go, walking speed, and Functional Gait Assessment). The test–retest reliability of the MFEtan balance test was evaluated by repeating the test after a 5-7 day interval. Statistical analyses, including intraclass correlation coefficients (ICCs), Bland–Altman analysis, and minimal detectable change (MDC), were applied to assess the consistency of test results and quantify measurement error. Correlations with established balance tests were analyzed to explore potential validity relations. Results and Discussion: The MFEtan balance test demonstrated good test–retest reliability for completion time (ICC = 0.85) and oversteps (ICC = 0.93). The MDC 95 for completion time was 9.49 seconds, with an MDC% of 26.68%. For oversteps, the MDC 95 was 1.8 steps, and the MDC% was 62.63%, reflecting higher relative measurement variability. Significant correlations were observed between oversteps and performance in the OLS ( r = −0.45, P =.001) and Functional Gait Assessment ( r = −0.54, P < .001), suggesting its association with both static OLS and dynamic functional gait assessment balance control. Conclusions: The MFEtan balance test demonstrates good test–retest reliability and shows partial construct validity, suggesting that it captures distinct aspects of balance performance. It may serve as a valuable complement to existing tools for monitoring balance changes and guiding interventions in high-functioning older adults, especially when traditional tools show ceiling effects.