Dual-scale assessment of motor dysfunction in older adults with locomotor dysfunction and its association with gait and muscle activation

Objective This study examined the reliability and validity of a combined 25-question geriatric locomotive function scale (GLFS-25) and Locomotion Dysfunction Grade scale (LDG) classification protocol in older adults with locomotor dysfunction, and explored which objective gait and muscle activation parameters were most strongly associated with GLFS-25 scores. Methods The GLFS-25 and LDG were used to assess 289 older adults with locomotor dysfunction, of whom 60 underwent gait analysis and surface electromyography (sEMG). Results Reliability analysis yielded a Cronbach’s α of 0.702 for the GLFS-25, indicating acceptable but modest internal consistency. Exploratory factor analysis extracted nine factors, accounting for 55.193% of the cumulative variance. Confirmatory factor analysis showed X 2 /df = 1.424, RMSEA = 0.038 (90% CI: 0.000–0.060), and SRMR = 0.055, indicating acceptable fit; however, CFI = 0.821, TLI = 0.801, and IFI = 0.830 were below 0.90, suggesting partial rather than strong construct validity. In exploratory ridge regression, the model showed an in-sample R 2 of 0.858, which should be interpreted with caution. Step length showed a positive association with the GLFS-25 score, while knee flexion during swing and the ratio of pressure onset time of the middle foot showed negative associations ( P < 0.05). However, individual coefficients should be interpreted cautiously. Conclusion The GLFS-25 demonstrated acceptable but modest reliability and partial construct validity in this population. In exploratory analyses, its scores showed a strong in-sample association with objective gait and sEMG measures. These findings are hypothesis-generating and require external validation in independent cohorts. Objective measures remain complementary to, rather than substitutes for, subjective assessment. Registration: ChiCTR2400087701.