Exploring the relationship between Alzheimer's disease and lower extremity isokinetic muscle strength in community-dwelling older adults: A cross-sectional observational study

Background Older adults diagnosed with Alzheimer's disease (AD) often experience diminished muscle strength, highlighting the continued importance of evaluating muscle function in this population. Objective To examine the relationship between AD and isokinetic lower limb muscle strength in older adults. Methods A cross-sectional observational study was conducted to examine the association between AD and lower limb isokinetic muscle strength in community-dwelling older adults. AD diagnosis was the independent variable; dependent variables included peak torque, average peak torque, and total work. A standardized isokinetic protocol adapted for older adults with cognitive impairment was used to assess knee (flexion/extension at 60°/s and 180°/s) and ankle (dorsiflexion/plantar flexion at 30°/s) strength. Crude and adjusted linear regression models evaluated statistical associations, with significance set at p ≤ 0.05. Results A total of 80 older adults were included, 50% of whom had a diagnosis of AD. The crude model's analysis showed an association between AD and all knee and ankle isokinetic measurements. When the models were adjusted, the association was maintained only for ankle peak torque (β1 = -16.23; p < 0.048) and ankle average peak torque (β1 = -13.65; p < 0.049) at 30°/s (plantar flexion). Conclusions Alzheimer's disease is associated with lower ankle plantar flexors isokinetic muscle strength in community-dwelling older adults. No significant associations between AD and knee (flexors and extensors) and ankle (dorsiflexors) isokinetic muscle strength were found.