Exploring the Center of Pressure Shift Feedback at Heel Strike to Modulate the Step Length

In a bipedal human locomotion, step length modulation is critical in determining the overall gait performance such as gait speed, anteroposterior (AP) ground reaction force, obstacle crossing, and turning. Training intervention based on the step length change feedback requires gait laboratory to measure the step length and hence training is restricted to the indoor settings. In this paper, we propose a novel center of pressure (CoP) based vibrotactile feedback step length training system (SLTS) to alter step length. Anterior/posterior location of the CoP at heel strike compared to the baseline was mapped to the anteriorly/posteriorly located tactors on the waist band. Four able-bodied participants were recruited for the experiment. Each participant was asked to walk on the walkway inside gait laboratory. Experiment was conducted in two different walking sessions i.e., baseline and the feedback session. During the baseline session, participants were asked to walk normally without any feedback. During the feedback session, participants walked while shifting the CoP anteriorly/posteriorly at heel strike with the feedback clue. With the feedback, posteriorly shifted CoP significantly enhances the step length (0.70±0.023m) whereas anteriorly shifted CoP significantly reduced the step length (0.48±0.029m) compared to the baseline (0.64±0.013m). The overall results reflect the potential of the SLTS in altering the step length with shift in the CoP at heel strike. In the future, SLTS can be miniaturized and integrated in the individual's activity of daily living as the step length trailing device.