Evaluating the Reliability of Markerless Gait Analysis: Insights from Theia3D

Summary

A recent study published in PeerJ assessed the reliability of Theia3D’s markerless motion capture system under varying clothing conditions during walking. The findings indicate that both tight and loose-fitting clothing yield consistent gait analysis results, with minimal variation observed between trials and sessions.

Research Overview

Study Aim: To evaluate the inter-trial and inter-session variation, and the effect of clothing within and between sessions on gait kinematics from Theia3D markerless motion capture software.

‍Methods: Twenty-two healthy adults walked along an indoor walkway while eight video cameras recorded their gait in both tight and loose-fitting clothing, during two sessions within 14 days of each other. Video data were analyzed using Theia3D to obtain the kinematic data for analysis.

‍Key Findings:

Inter-trial Variation: Averaged less than 2° across all joints and planes.
Inter-session Variation: Averaged less than 3°, indicating high consistency between sessions.
Inter-session-Clothing Variation: Averaged less than 3.5°, suggesting minimal impact of clothing type on gait measurements.
Root Mean Square Differences (RMSD): Less than 2° between clothing conditions, reinforcing the system’s robustness to clothing variations.

‍Comparison to Existing Research: The observed variations were smaller than those reported in previous studies, potentially due to software updates enhancing Theia3D’s reliability.

Implications for Biomechanics Research

These findings support the use of markerless motion capture systems like Theia3D in both research and clinical settings. The low inter-session variability and minimal impact of clothing type simplifies data collection protocols, allowing participants to wear their usual clothing without compromising data quality, even across separate sessions. This advancement could lead to broader applications in gait analysis, including in populations where traditional marker-based systems are impractical or introduce additional variability due to operator or laboratory.

The Role of Markerless Motion Capture

Theia3D’s markerless system eliminates the need for placing reflective markers on participants, reducing preparation time and potential discomfort. Compared to traditional marker-based systems, markerless technology offers:

Increased Efficiency: Streamlined data collection processes.
Improved Participant Engagement: Allowing populations that might not typically participate in research the opportunity to participate.
Reduced Inter-Rater Variation: Automated data analysis minimizes human errors associated with marker placement.
Increased Ecological Validity: Participants can perform naturally in their own attire and can be tested in a more natural environment.

Future Research Directions

While this study demonstrated reliability in healthy adults, further research is needed to:

Assess Clinical Populations: Evaluate the system’s performance in individuals with gait abnormalities.
Explore Longitudinal Consistency: Examine reliability over extended periods (>2 weeks) and multiple sessions (>3).
Collect Field Data: Assess populations in their natural environment.

Full Study & Further Reading

For a detailed understanding of the study’s methodology and results, read the full article here.

This is the second study assessing the impact of clothing type on the repeatability of gait kinematics using Theia3D. Previous research published in the Journal of Biomechanics can be found here.

‍Want to explore Theia3D for your biomechanics studies? Contact us for a demo.