Augmented-reality-based walking test battery in young and older adults: intra-rater reliability and ecological validity

Several walking tests assess mobility and fall-related function in older adults, but their clinimetric properties remain insufficiently documented across task conditions and assessment environments. Augmented-reality may support standardized, instrumented assessment, but its ecological validity remains unclear. This study assessed intra-rater reliability and ecological validity for a walking test battery in young and older adults. Healthy young and older adults performed four clinical walking tests (straight-walking, Figure-of-8 Walk, Timed Up-and-Go and obstacles crossing) in real-world and augmented-reality, under single-task (ST) and arithmetic dual-task (DT) conditions. Completion time was used to assess within-session intra-rater reliability, agreement, and equivalence using a predefined margin (± 1.0 s). Thirty-five young adults and 26 older adults were analysed. Across both environments (real-world and augmented-reality), walking-test completion times showed moderate-to-excellent reliability in young adults (ICC 0.740–0.948). In older adults, ST reliability was generally good-to-excellent, except for obstacle crossing in augmented-reality (ICC = 0.719), while DT reliability was more variable, particularly in augmented-reality (ICC 0.605–0.925). All tests and conditions met the predefined ± 1.0 s equivalence criterion between real-world and augmented-reality in both age groups. Augmented-reality-based walking assessment showed favourable agreement with real-world performance across tests, age groups and task conditions. Intra-rater reliability was generally satisfactory, although DT performance was more variable in older adults, with lower reliability for some augmented-reality tests. - Augmented-reality-based walking times agreed well with real-world performance in both groups. - Augmented-reality-based test times showed good-to-excellent reliability, except in DT conditions in older adults. - DT variability in older adults may reflect both reliability limits and adaptive strategies. - Further validation is needed before augmented-reality walking tests can inform fall-risk assessment.