Towards Inertial Sensor Based Mobile Gait Analysis: Event-Detection and Spatio-Temporal Parameters.

Area of Science:

• Biomechanics
• Wearable Technology

Background:

• Gait analysis is crucial for assessing mobility and diagnosing conditions.
• Inertial Measurement Units (IMUs) offer a portable alternative to traditional motion capture systems.

Purpose of the Study:

• To evaluate the validity and test-retest reliability of an IMU system for gait analysis.
• To compare IMU-derived spatio-temporal parameters (STPs) against an optical motion capture (OMC) system.

Main Methods:

• Twenty-four healthy subjects performed a 6-minute walk test wearing seven IMUs and retroreflective markers.
• A kinematic approach estimated gait events, calculating twelve STPs.
• An optical motion capture (OMC) system served as the reference standard.

Main Results:

• The IMU system achieved a 99% event detection rate with minimal offset (<0.017s).
• Relative RMSE for most STPs was below 4.40%, but higher for parameters requiring bilateral spatial data (e.g., step length 6.69%).
• Step width (34.34%) and swing width (35.20%) exhibited the highest RMSE, with test-retest reliability as low as 0.25 for step width.

Conclusions:

• The IMU system demonstrates good validity and reliability for several gait parameters.
• Further refinement is needed for IMU-based measurement of lateral foot distances.
• The system shows promise for clinical gait analysis and future research.