Figure 4. Correlations for knee valgus angle measurement with Human, OpenPose, and 3D. The figures illustrate the knee valgus angles or its excursion at the following specified timings or duration. Knee varus angles show positive values, and the valgus angles show negative values. Human: human visual detection-based motion analysis; OpenPose: OpenPose-based motion analysis; 3D: three-dimensional motion analysis. a: initial contact; b: lowest center of gravity (COG) after landing; c: from the initial contact to the lowest COG after landing. No significant differences were found at landing phase or knee valgus excursion.