Smart Footwear

Researchers at the RWTH Department of Medical Information Technology and the Indian Institute of Technology Madras have developed a novel sensing system capable of assessing not only how a person walks, but also where. The technology enables simultaneous analysis of spatiotemporal gait parameters and detection of walking surfaces—using electrical impedance measured between a pair of specialized shoes and the ground during walking. 

One System, Two Insights

Gait analysis plays a critical role in rehabilitation, neurology, and sports science. However, most wearable systems focus exclusively on movement, overlooking the influence of the walking surface despite its significant impact on gait patterns. This limits the accuracy and real-world applicability of many current solutions.

The newly developed system addresses this by combining both functions in a single wearable: sensor-equipped shoes that measure electrical impedance through the ground. The system forms a closed electrical circuit between a sensor shoe, a non-sensor shoe, and the walking surface. As the user walks, impedance values shift based on body movement and the type of ground material due to changes in capacitive coupling between the shoes and the surface.

These impedance patterns are processed by a dedicated algorithm to extract spatiotemporal gait parameters such as stride length, cadence, and stance time, while also classifying surface types like grass, carpet, rubber, asphalt, or vinyl. This enables real-time, context-aware gait analysis beyond laboratory settings.

The system’s portability and non-invasiveness open up practical use cases in clinical gait analysis, rehabilitation, smart footwear, and assistive mobility technologies, particularly for supporting older people in everyday environments.

System Validation and Application Potential

The system was validated with human participants walking on various surfaces. Impedance data was benchmarked against force plate measurements, confirming the prototype’s reliability under real-world conditions. Features extracted from the impedance waveform enabled accurate surface classification across all tested environments. Compact and easily integrated into everyday footwear, the system supports continuous, long-term monitoring—unlocking new possibilities for both medical and consumer applications.

The invention is protected by a patent jointly filed by RWTH Aachen and IIT Madras. Strategic intellectual property protection secures the scientific results and supports their translation into real-world impact. In February 2025, the findings were published in IEEE Transactions on Instrumentation and Measurement, highlighting the scientific merit and rigor of the approach.