Ankle musculature and postural stability in elderly fallers
Falls represent a significant cause of mortality and morbidity in elderly populations. A large body of evidence suggests that an age-related decrease in postural stability is a causative factor for falls amongst the elderly. It has been previously observed that standing postural stability is negatively correlated with maximum isometric torque at the ankle joint, indicating that weakness of the ankle musculature contributes to falls in the elderly. However, the specific relationship between this weakness and postural stability has not been described. The aim of this study was to establish if the mechanical contribution of ankle muscles in the upright stance differed between young adults (n=10), elderly non-fallers (n=12) and elderly fallers (n=20).
42 individuals underwent postural stability testing using a force platform and concurrent EMG assessment of the bilateral plantarflexor and dorsiflexor musculature. Results showed a significant increase in postural sway and ankle torques in the group of elderly fallers when compared to the elderly non-fallers and young adults. This correlation was specifically demonstrated by the gradual increase in Plantarflexor torques seen between the young adults (least torque), elderly non-fallers (moderate torque) and the elderly fallers (most torque).
Simply put, the weaker the ankle musculature, the more relative torque was produced and the lower the postural stability. The results of this study suggest that rehab programs which aim to increase the maximum capacity of force produced by the ankle musculature, specifically the plantarflexors, may increase the postural stability of elderly populations at risk of falling.
> From: Cattagni et al., Exp Gerontol 77 (2017) 38-45. All rights reserved to Elsevier Inc. Click here for the online summary.