Exploring the role of ankle muscle function in gait impairments and fall risk in Parkinson's disease

Introduction: Parkinson's disease (PD) significantly impacts mobility, with gait disturbances and muscle impairments contributing to a fall risk five times higher than similarly aged adults. Falls significantly impact the quality of life in those with PD, yet the role of ankle muscle function in gait disturbances remains underexplored. This study investigated whether deficits in ankle force and steadiness contribute to gait variability and fall risk, potentially uncovering therapeutic targets for fall prevention in individuals with PD compared with age-matched older adults (OA). Methods: A case-control design involving 15 individuals with PD and 15 age-matched OA patients was employed. Gait variables and variability were assessed during a 12-m walking task. Ankle muscle strength and force steadiness were measured using an isokinetic dynamometer. Statistical analyses, including Pearson and Spearman correlation coefficients, examined relationships between muscle function and gait variability. Results: The PD group exhibited reduced ankle plantarflexion and dorsiflexion strength compared to OA (p < 0.05). Force steadiness was impaired in the PD group, particularly at lower submaximal intensities. In those with PD, lower plantarflexor (rho = -0.69) and dorsiflexor (rho = -0.67) strength were significantly correlated with a higher number of falls, as was impaired force steadiness (p < 0.05). No significant relationships were observed in the OA group. Conclusions: These findings underscore the critical role of ankle muscle function in influencing gait variability in individuals with PD. The associations between reduced muscle strength, force steadiness, and increased gait variability highlight the potential of targeted ankle muscle-strengthening interventions to mitigate gait disturbances and reduce fall risk in this population.