Dynamic stability is tied to gait assistance when walking with a hip exoskeleton

As age increases, factors such as visual impairments, joint instability, muscle weakness, and unreliable postural reflexes contribute to reduced stability and a higher risk of fall. Weak hip abductors/adductors further increase this risk. Hip flexors and extensors, which govern sagittal-plane limb advancement and propulsion, also play a critical role in dynamic walking stability. While traditional assistive devices support mobility, exoskeleton technology may improve walking stability and reduce fall risk. This study examines the effects of five exoskeleton assistance timings and two torque magnitudes on gait stability and step characteristics. We hypothesized hip assistance would increase MoS (particularly in the ML direction) through changes in foot placement and that nonlinear COM metrics would change in a direction consistent with stability adaptations. Ten healthy young adults (four males, six females; age: 27.6 ± 5.9 years, body mass: 65.3 ± 13.1 kg, height: 1.66 ± 0.08 m) were assessed for Margin of Stability (MoS), step characteristics, and center of mass nonlinearity. Statistical analyses included linear mixed-model ANOVAs, paired t-tests, and Wilcoxon signed-rank tests. Exoskeleton assistance increased MoS in medial-lateral (ML) and anterior-posterior (AP) directions. Wider, more variable steps and increased gait irregularity suggest extensive adaptation is required. While hip exoskeletons improve walking stability, further research is needed to understand long-term adaptation and daily use. Future studies should explore larger clinical populations and the long-term implications of exoskeleton-assisted walking.