Figure 6. Schematic illustration of 2D perspective projection, highlighting potential sources of error in drone-based velocity measurements. The detection bounding box (green) identifies the tracking point Cj, which is subsequently mapped to the real-world ground position Bj. However, particularly during dynamic sprinting postures, the athlete's actual biological center of mass (Aj) may deviate from this projected point, leading to discrepancies in kinematic parameter estimation.