An exploratory comparative analysis of kinematic characteristics in two elite Chinese show jumping riders

Three-dimensional rider kinematics across jumping phases and obstacle heights remain sparsely documented in elite Chinese show jumping. This exploratory case study examined angle-related kinematic characteristics in two elite Chinese riders under field-based jumping conditions.

Three-dimensional video-based kinematic analysis was performed using the Simi Motion 3D system with direct linear transformation (DLT)-based camera calibration and three-dimensional reconstruction of selected anatomical landmarks. Two elite male riders rode the same experienced horse over the second vertical obstacle of a combination at 85, 105, and 140 cm. One successful trial per rider was analyzed at each obstacle-height condition. The approach, take-off, flight, and landing phases were segmented, and bilateral landmark-derived angle-related kinematic variables corresponding to the shoulder, hip, knee, and ankle regions were summarized using phase-averaged values and within-phase standard deviations, which represented temporal variability within a single trial. Between-rider differences in phase-averaged values were defined as Δmean = mean_A - mean_B. Only case-level descriptive analyses were performed; no inferential statistical tests were conducted.

Between-rider kinematic differences did not show a consistent monotonic increase across obstacle-height conditions. Instead, the measures showing larger between-rider differences shifted across obstacle-height conditions and jumping phases. During take-off, the right shoulder-related measure showed the clearest directional change, with Δmean values changing from -39.91° at 85 cm to -6.26° at 105 cm and +26.35° at 140 cm. During approach, hip-related differences showed a relatively consistent direction across conditions. During flight and landing, the measures showing larger differences shifted across body regions and involved both proximal and distal angle-related measures.

These case-level findings indicate that the pattern and direction of between-rider differences varied across obstacle-height conditions and jumping phases. Because only two riders and one successful trial per rider at each condition were analyzed, the observed patterns cannot be assumed to represent stable rider-specific characteristics. Larger samples, repeated trials, quantitative horse-related measurements, and longitudinal designs are needed to examine the stability and practical relevance of these patterns.