Evaluating determinants of rider performance in high-level dressage riders

Many factors influence the overall score for a dressage test, which makes it challenging and complex to establish key performance determinants. The aim was to identify an objective locomotory measure to quantify overall rider performance in dressage. The chosen variable should be both easy to collect and useful in a practical context. Twenty dressage horse/ rider combinations (Int1-GP) were equipped with inertial measurement units (IMU’s, 200 Hz) attached to the rider’s sacrum and thorax. Transverse dynamic trunk symmetry and pelvis symmetry (symmetry measures) and trunk-to-pelvis 3-dimensional coordination variability (within rider coordination measure) were collected from the IMU’s during straight line walk, trot and canter on left and right reins with ≥9 strides/condition. Sixteen United States Dressage Federation senior judges evaluated the movements of interest from video footage with 2-3 judges scoring each rider’s performance in the movements of interest and awarding collective scores to represent the overall impression of each rider’s performance. Stepwise linear regression was used to seek associations between objective measurements from the IMUs and subjective scores awarded by the judges. The variable dynamic trunk symmetry was the strongest predictor of collective scores, specifically the score for rider position (R=0.357, P=0.001). The rider’s dynamic pelvic symmetry was a strong predictor of the judged score for the walk (R=0.607, P=0.010), but no relationships were found between objective and judged scores for trot or canter. The overall impression of trunk posture may be influential in judges’ collective scores. Symmetrical pelvic motion appears to be a key factor in producing a high-quality walk