Stepping boundary of external force-controlled perturbations of varying durations: Comparison of experimental data and model simulations

摘要

This study investigated the stepping boundary - the force that can be resisted without stepping - for force-controlled perturbations of different durations. Twenty-two healthy young adults (19-37 years old) were instructed to try not to step in response to 86 different force/time combinations of forward waist-pulls. The forces at which 50% of subjects stepped (F-50) were identified for each tested perturbation durations. Results showed that F50 decreased hyperbolically when the perturbation's duration increased and converged toward a constant value (about 10% BW) for longer perturbations (over 1500 ms). The effect of perturbation duration was critical for the shortest perturbations (less than 1 s).