Validity of OpenCap to Identify Marker Locations on the Lower Limb
Advisor(s)
Louis DiBerardino
Confirmation
1
Document Type
Paper
Location
ONU McIntosh Center; Dean's Heritage
Start Date
21-4-2026 3:25 PM
End Date
21-4-2026 3:40 PM
Abstract
Markerless motion capture provides an accessible, cost-effective, and efficient alternative for assessing biomechanics, and can broaden accessibility to those previously constrained by the high cost and equipment requirements of marker-based technologies. While previous research has primarily focused on joint angle and relative motion validation using OpenCap, this study aims to assess the system’s accuracy in identifying lower-limb marker locations. For 10 subjects, knee and ankle position data were captured simultaneously using a three-dimensional motion capture system and OpenCap during a squat and a walk. Results were compared visually, and RMS error was calculated. OpenCap performed well during the squat, but issues arose during the walking trial. Based on the results, OpenCap is well suited for “stationary” tasks near its origin. However, further data analysis is being done to determine the validity of OpenCap for dynamic movement.
Recommended Citation
Arno, Madison, "Validity of OpenCap to Identify Marker Locations on the Lower Limb" (2026). ONU Student Research Colloquium. 40.
https://digitalcommons.onu.edu/student_research_colloquium/2026/Papers/40
Open Access
Available to all.
Validity of OpenCap to Identify Marker Locations on the Lower Limb
ONU McIntosh Center; Dean's Heritage
Markerless motion capture provides an accessible, cost-effective, and efficient alternative for assessing biomechanics, and can broaden accessibility to those previously constrained by the high cost and equipment requirements of marker-based technologies. While previous research has primarily focused on joint angle and relative motion validation using OpenCap, this study aims to assess the system’s accuracy in identifying lower-limb marker locations. For 10 subjects, knee and ankle position data were captured simultaneously using a three-dimensional motion capture system and OpenCap during a squat and a walk. Results were compared visually, and RMS error was calculated. OpenCap performed well during the squat, but issues arose during the walking trial. Based on the results, OpenCap is well suited for “stationary” tasks near its origin. However, further data analysis is being done to determine the validity of OpenCap for dynamic movement.