Validation of a Commercially Available IMU-Based System Against an Optoelectronic System for Full-Body Motor Tasks

Area of Science:

• Biomechanics
• Human Movement Analysis
• Wearable Technology

Background:

• Optoelectronic motion capture systems are the gold standard for kinematic analysis but are expensive and lab-bound.
• Inertial measurement units (IMUs) offer a portable, cost-effective alternative for motion tracking.
• Validating IMU systems against gold standards is crucial for their clinical adoption.

Purpose of the Study:

• To validate a commercial multi-sensor inertial measurement unit (IMU) system against an optoelectronic motion capture system.
• To assess the accuracy of IMU-based range of motion (ROM) measurements for lower limb, trunk, and upper limb movements.
• To determine the clinical applicability of IMU technology in motion analysis.

Main Methods:

• Fifteen healthy participants performed various single- and multi-joint movements.
• Simultaneous motion data acquisition using both an IMU system and an optoelectronic motion capture system.
• Comparison of range of motion (ROM) values between the two systems, including statistical analysis of differences, errors, and correlations.

Main Results:

• The IMU system demonstrated high concurrent validity with the reference system (correlations r ≥ 0.77).
• Root mean square error values were generally below 7°, with similarity percentages exceeding 97%.
• Systematic biases were minimal (≤3.9°), and limits of agreement were clinically acceptable.

Conclusions:

• The validated IMU system provides statistically and clinically comparable ROM estimates to optical systems.
• The system's portability, ease of use, and affordability make it a promising tool for motion analysis in clinical and remote rehabilitation.
• Future research should focus on validation in pathological populations and during extended monitoring periods.