The purpose of this study was to analyze some block constraints in Elite Male Volleyball. So, were established the relationship between: (i) blocking system and block effectiveness; (ii) blocking system and block opposition; (iii) block effectiveness and set outcome. There were analyzed 4351 sequences, corresponding to 97 sets, of twelve men’s national teams participating in Final Phase of World Cup 2007. The chi-square with adjusted residual to test the association between the variables was applied. For reliability, results showed percentages of agreement above 80%. The results showed a significant relationship between block effectiveness and blocking system. The man-to-man blocking system increase the occurrence of block-out and block continuity 2 and reduce the occurrence of block continuity 3 and block point; the zone-blocking system increases the occurrence of block point and reduces the occurrences of block-out. Moreover a significant relationship between blocking system and the numbers of blockers were established; the man-to-man blocking-system increase the occurrence of single block and reduce the occurrence of double and triple block; zone-blocking system increase the occurrence of double and triple block and reduce the occurrence of open double and single block. Block effectiveness and set final outcome, showed an independent relationship.