Background: Like most aesthetic sports, judging performance in equestrian vaulting is subjective. The complexity of judging often exceeds human cognitive capacities and can give rise to bias. The horse score makes up 25% of the total score, including the quality of the canter and training level of the horse (A1 score), the execution of the performance and the horse’s willingness and behaviour (A2 score). Objectives: The aim of this study was to compare A1 and A2 scores from judges with objective measurements. Study design: cross-sectional study design Methods: The study explored the alignment between the 6 scores of A1, the A2 score, and 10 measured locomotor parameters in 33 international level vaulting horses. The horses were equipped with an inertial measurement unit (128 Hz) fixed to the sternum to calculate positions and movements and to calculate a quality index. Five international judges scored the relaxation, connection, straightness, impulsion, rhythm, collection and vaultability from the videos in random order. Results: A horse with at least one good score had only good scores and each note was correlated with the same locomotor parameters. A canter considered to be good by the judges was one with good elevation (14 ± 1 vs 13 ± 2 cm; 0.013), good propulsion (6.7 ± 1.4 vs 5.7 ±1.7 m/s 2; 0.005) and good regularity of the three beats (0.016 ± 0.004 vs 0.019 ± 0.004 m/s 3; 0.018), with the horse slightly inclined to the inside of the circle, balanced on their hindlimbs and with a light forehand. Main limitations: Use of videos for judging Conclusions: These observables seemed to be decisive in assessing the quality of the canter and are of interest in terms of decision support in the context of initial and ongoing training for judges and for considering continuous optimisation of the scoring system.