Foot progression angle estimation using a single foot-worn inertial sensor.

Area of Science:

• Biomechanics
• Wearable Technology
• Gait Analysis

Background:

• Foot progression angle (FPA) is crucial for reducing knee adduction moment.
• Existing measurement systems are limited to laboratory settings or affected by environmental factors like magnetic distortion.
• A novel approach using a single foot-worn inertial sensor is proposed.

Purpose of the Study:

• To develop and validate a novel method for estimating foot progression angle (FPA) using a single foot-worn inertial sensor.
• To overcome the limitations of current FPA measurement systems, enabling use in diverse environments.
• To facilitate feedback applications for patients with gait disorders.

Main Methods:

• Utilized a dynamic step frame recalculated per stance phase to determine foot trajectory.
• Calculated FPA as the angle between walking direction and the dynamic step frame.
• Validated the approach with five subjects across normal, toe-in, and toe-out gait types.

Main Results:

• The proposed inertial sensor approach estimated FPA with a maximum mean error of approximately 2.6° across all gait conditions.
• The system demonstrated a significant ability to differentiate between normal, toe-in, and toe-out gait patterns.
• The method successfully estimated FPA differences without requiring a magnetometer.

Conclusions:

• The novel approach effectively estimates FPA variations using a single inertial sensor, independent of heading references.
• This technology enables practical, real-world FPA feedback applications for gait disorder management.
• The system functions reliably outside traditional gait labs and in magnetically challenging environments.