The aim of this study was to pilot the assessment of sport predispositions in warmblood horse breeds, both domestic and foreign, and to evaluate factors influencing their performance. Data from 293 horses (725 starts) competing in national Grand Prix events with obstacle heights of 140–145 cm were analysed using general mixed models. The origins of Polish Halfbred Horses were examined, and correlations between results in the Young Horse Championships and later Grand Prix performance were assessed. Results showed that performance is significantly influenced by genetic factors, such as breed and sex, and by the random effect of the rider. Stallions, German breeds, and horses aged 15–18 years performed best. Analysis of breed distribution and pedigrees revealed the growing importance of German, Belgian, and Dutch horses in national competitions. Positive correlations between early evaluation and later performance support the use of these data in assessing utility and breeding value. Despite low repeatability, competition results remain a valuable indicator of performance and breeding potential