Markerless motion capture estimates of lower extremity kinematics and kinetics are comparable to marker-based across 8 movements

Abstract

Motion analysis is essential for assessing in-vivo human biomechanics. Marker-based motion capture is the standard to analyze human motion, but the inherent inaccuracy and practical challenges limit its utility in large-scale and real-world applications. Markerless motion capture has shown promise to overcome these practical barriers. However, its fidelity in quantifying joint kinematics and kinetics has not been verified across multiple common human movements. In this study, we concurrently captured marker-based and markerless motion data on 10 healthy subjects performing 8 daily living and exercise movements. We calculated the correlation (Rxy) and root-mean-square difference (RMSD) between markerless and marker-based estimates of ankle dorsi-plantarflexion, knee flexion, and three-dimensional hip kinematics (angles) and kinetics (moments) during each movement. Estimates from markerless motion capture matched closely with marker-based in ankle and knee joint angles (Rxy≥ 0.877, RMSD ≤ 5.9°) and moments (Rxy≥ 0.934, RMSD ≤ 2.66 % height × weight). High outcome comparability means the practical benefits of markerless motion capture can simplify experiments and facilitate large-scale analyses. Hip angles and moments demonstrated more differences between the two systems (RMSD: 6.7° – 15.9° and up to 7.15 % height × weight), especially during rapid movements such as running. Markerless motion capture appears to improve the accuracy of hip-related measures, yet more research is needed for validation. We encourage the biomechanics community to continue verifying, validating, and establishing best practices for markerless motion capture, which holds exciting potential to advance collaborative biomechanical research and expand real-world assessments needed for clinical translation.

Evaluation of the Margin of Stability during Gait Initiation in Young Healthy Adults, Elderly Healthy Adults and Patients with Parkinson’s Disease: A Comparison of Force Plate and Markerless Motion Capture Systems

“…A markerless prenium system was chosen in the present study; it has been shown to provide data on lower limbs gait kinematics that are as reliable as those from marker-based systems, as revealed by the inter-session variability, inter-trial variability and inter-session variability ratios [24]. Estimates from this markerless motion capture system were also very similar to those obtained from marker-based motion capture in terms of ankle and knee joint angles and moments [23,29]. This system only requires calibration of the area captured by the cameras.…”

Interference and Motor Memory Consolidation Effects of Sequential Gait Interventions: A randomized controlled trial

“…Infrared-re ective markers were placed on the participants' lateral trochanters, toe, menisci, heel, malleoli, and an additional marker was placed on the individuals' sternum for ease of marker calibration during gait analysis. These marker placements allow processing of lower limb joint kinematics along with spatiotemporal gait analysis in the sagittal plane, and it is also consistent with a subset of the CAREN system's HBM lower body model [50,51,52]. Eleven infrared-re ective markers were placed at locations indicated with red circular dots: lateral trochanter, lateral malleoli, menisci, heel, toe, and bottom of the sternum.…”

The Use of Motion Capture Technology in 3D Animation

“…The results demonstrated a significant improvement in scene initialization and infant motion tracking; however, artifacts were still noticeable in the reconstruction, partly due to imperfect segmentation masks. In contrast to [33], [34] analyzed crucial movements to assess in-vivo human biomechanics using the Markerless motion capture system assisted by Microsoft Kinect. In this system, the camera has depth and infrared sensors to track body movements without the need for physical markers.…”