Loaded versus unloaded gait balance stability: A measure of dynamic walking

Several stability indices exist in the literature, each within their contexts and perspectives of quantification. However, no relevant index for the quantification of gait balance stability has been rigorously developed. Here, the novel Dynamic Gait Measure (DGM) is used to characterize the distinct gait balance stability of loaded walking, as compared to normal human walking. The DGM quantifies the normalized effects of inertia of a given gait with respect to the time-varying foot support region. The DGM is formulated in terms of the gait parameters reflecting a given gait strategy, and is extended to multiple steps of the gait cycle. The altered gait kinematics observed during load carriage (decreased single support duration, inertia effects, and step length) results in decreased DGM values (p < 0.0001), indicating that loaded walking is more statically stable compared with the unloaded walking. The DGM is compared with other common gait stability indices to validate its unique ability to catch the alteration (due to load carriage) in its corresponding gait stability characteristics.