Ankle joint muscle force generation patterns between elderly fallers and non-fallers

Falls are a major cause of injury in elderly individuals, with some cases resulting in long hospital stays or even fatalities. Muscle weakness is a significant risk factor for falls, and Musculoskeletal (MSK) modeling, such as OpenSim, is a valuable tool that can provide data on muscle activations and forces during gait through movement simulations. The aim of this study was to compare ankle joint muscle force generation patterns during gait, as calculated by OpenSim, between elderly fallers and non-fallers. The study involved six elderly participants, divided into fallers (n=3) and non-fallers (n=3) groups based on their score on the John Hopkins fall risk assessment tool. The participants were asked to walk at their normal pace for one minute on a split-belt treadmill, and their gait cycles were recorded using a 3D motion capture system. The recorded data was then used to determine muscle activations and forces of the left limb for each gait cycle using a generic full body MSK model in OpenSim. Statistical Parametric Mapping (SPM) was used to compare the time curves of the ankle joint plantar and dorsi flexors normalized to weight forces between the two groups. The results showed significant differences in muscle force production during gait between fallers and non-fallers, with non-fallers demonstrating higher muscle force values. Fallers showed lower muscle force values in the plantar flexors, which suggests weaker plantar flexors, a known risk factor for falls. This finding highlights the importance of identifying plantar flexor weakness in the elderly as a preventive measure for falls.

A. Gkrekidis, G. Giarmatzis, D. Menychtas, P. Manaveli, E. Kouli, A. M. Kanavaki, V. Gourgoulis, E. Douda, I. Smilios, M. Michalopoulou, G. Sirakoulis, N. Aggelousis