Effect of Foot-floor Friction on Slip- or Trip-induced Falls during Walking

Abstract

In the current study, we investigated the influence of foot-floor friction to fall probability using computer simulation. Neuro-musculoskeletal models simulating gaits in a young adult, an elderly non-faller, and an elderly faller were developed by tuning neural parameters. An elderly non-faller gait model showed smaller stride length, cadence, and foot clearance, while an elderly non-faller gait model showed further smaller stride length, cadence, and foot clearance, as well as larger gait variability. To alter the foot–floor friction, we changed the maximum value of traction coefficient of the foot-floor contact which corresponds to the static friction coefficient. The young adult and the elderly non-faller gait models showed slip-induced falls only when the static friction coefficient was small. However, while the elderly faller gait model showed slip-induced falls when the static friction coefficient was small same as other models, the elderly faller gait model also showed trip-induced falls when the static friction coefficient was large. Thus, we found that, especially when gait has smaller stride length/cadence/foot clearance as well as larger gait variability which is shown in elderly fallers, the influence of foot-floor friction is significant and the higher friction is not necessarily good for a stable and safe walking.