Soft wearable back-support cuts fall risk with adjustable stiffness

A team led by Hyunglae Lee from Arizona State University investigated the effectiveness of a soft wearable back-support device with adjustable stiffness in improving postural stability during trip-like perturbations. The study, presented at the 2026 IEEE BioRob conference, used two experimental paradigms: perturbed standing and perturbed walking. Healthy subjects performed trials under three conditions: no device, low-stiffness device, and high-stiffness device. Whole-body stability was quantified using the minimum Margin of Stability (MOS) at the point of maximal instability, a metric from biomechanics that measures how close the body's center of mass is to the base of support.

The results demonstrated clear benefits. In standing perturbations, MOS increased significantly with device stiffness—higher stiffness provided greater stability. In walking perturbations, both low and high stiffness conditions improved MOS compared to wearing no device, but the difference between stiffness levels was not statistically significant. This suggests that even a low-stiffness setting can effectively enhance reactive balance control during walking, while standing scenarios may benefit from higher stiffness. The device itself is soft and wearable, using variable stiffness to dynamically assist the lower back, making it comfortable for daily use.

The findings have important implications for fall prevention, especially in elderly populations and workers exposed to trip hazards. Future research will focus on personalized stiffness optimization based on individual gait and perturbation characteristics. The device represents a promising step toward practical, non-intrusive wearable robotics that can react to unexpected perturbations in real time, potentially reducing the risk of serious injuries from falls.