In Vivo Measurement of Wrist Movements during the Dart-Throwing Motion Using Inertial Measurement Units

Area of Science:

• Biomechanics
• Human Motion Analysis
• Wearable Technology

Background:

• Dart-throwing motion (DTM) involves complex wrist movements relevant to daily activities.
• Assessing DTM clinically is challenging due to its intricate nature.
• Comparison of motion capture systems for DTM is needed.

Purpose of the Study:

• To compare an inertial measurement unit (IMU)-based system with an optoelectronic motion capture system for DTM analysis.
• To evaluate the accuracy and reliability of IMUs for complex wrist kinematics.
• To explore the clinical applicability of IMUs in dynamic wrist movement assessment.

Main Methods:

• Ten healthy subjects performed DTM using both IMU sensors and skin markers for optoelectronic capture.
• Maximum range of motion was calculated for both systems.
• Mean absolute differences between the systems were determined.

Main Results:

• In the flexion-extension plane, both systems yielded a 100° range of motion with an 8° mean absolute difference.
• In the radial-ulnar deviation plane, the optoelectronic system recorded 48° and IMUs recorded 59°, with a 17° mean absolute difference.
• Discrepancies highlight challenges in comparing different motion capture systems for complex movements.

Conclusions:

• Comparing kinematic data from different motion capture systems for complex movements presents challenges.
• Inertial measurement units are a promising technology for future clinical applications in dynamic and coupled wrist movements.
• Potential sources of error and solutions for IMU-based motion analysis were discussed.