Verification of reliability and validity of motion analysis systems during bilateral squat using human pose tracking...

Area of Science:

• Biomechanics
• Human Motion Analysis
• Computer Vision

Background:

• OpenPose is a human tracking algorithm capable of detecting joint points and calculating joint angles.
• The reliability and validity of OpenPose for motion analysis remain underexplored.
• Clarifying OpenPose's accuracy is crucial for its adoption in research and clinical settings.

Purpose of the Study:

• To evaluate the reliability and validity of OpenPose for human motion analysis.
• To compare joint angle measurements from OpenPose against a gold-standard 3D motion capture system (VICON).

Main Methods:

• Twenty healthy subjects performed bilateral squats.
• Joint angles (trunk, hip, knee, ankle) were measured using both OpenPose and VICON.
• Test-retest reliability was assessed using ICC (1, 3).
• Validity was evaluated through linear regression and ICC (2, 1) against VICON data.
• Bland-Altman analysis was used to assess agreement and identify biases.

Main Results:

• OpenPose demonstrated almost perfect test-retest reliability (ICC (1, 3)).
• High agreement (ICC (2, 1)) was found for trunk, knee, and ankle joints (almost perfect/substantial).
• Hip joint analysis showed fair agreement (ICC (2, 1)).
• Fixed biases were observed for knee and ankle joints; proportional biases for trunk and hip joints.

Conclusions:

• OpenPose-based motion analysis is reliable and offers a cost-effective, user-friendly alternative to traditional methods.
• Further research is needed to address identified biases for enhanced clinical utility.
• Correction strategies for fixed and proportional biases will improve the accuracy of OpenPose in clinical applications.