摘要：Introduction: The aim of this study compare the influence of rules changes on shots performance considering three different levels, in the final classification, between two male European championships with different rules. Material and Methods: All shots made by the first, second, sixth, seventh, eleventh and twelfth classified in 27th European Championship in 2006 (Belgrade, Serbia) and all shots made by the first, second, eighth, ninth, fifteenth and sixteenth classified in 34th European Championship in 2020 (Budapest, Hungary) were analysed. Results: The total sample was composed of 3,467 shots (1,813 in Belgrade Championship and 1,654 in Budapest). The study was developed with an observational design. Three observers with more than 300h of experience in observational studies of water polo consensually quantified all the actions. Discussion: The effectiveness of the shots, considering only those that have taken place in equality and counterattack, shows greater scoring efficiency by the HL teams against the WL; and specifically among the shots made with a balanced period score (+-1) (F = 3.637; p = .032; S.E. = .107) and unbalanced (+-2) (F = 3.835; p = .027; S.E. = .106) stand out. In inequality situations its noted the existence of lower efficiency for WL teams when shot from the center stands out against the HL. Conclusions: It is concluded that the regulatory changes have reduced the importance, in the performance of the teams, of effectiveness in situations of inequality, giving rise to a more dynamic game, balanced according to the skill of the players and not their body size, but above all less static.
