The effect of rule changes on match and ball in play time in rugby union.

In 1999, the International Rugby Board introduced a number of rules to rugby union in order to address perceived problems that were happening in the game (Davies, 1999; Kervin, 1999). These involved the amendment of current rules and the introduction of new facets to the game. The changes were introduced in order to improve safety, increase competition and continuity, which would address criticism from the players, spectators and the media. It is hypothesised that the changes will have a significant effect on the game in terms of match and ball in play time. The paper will investigate the changes that occurred within the game of rugby union over a five year period (1999-2003) and will examine games played in the Six Nations, Tri Nations, European Cup and Super 12 competitions (n=496).

Match time was defined as the time taken to complete the match. The time starts from when the team starting the match kicks off to the time the referee ends the match. Ball in play time was defined as the amount of time the ball is in the possession of any of the players or is in a position where either team can contest the ball. Time when play has been stopped by the referee is considered out of play and does not contribute to ball in play time.

The data were collected using a real-time data capture system, which had been written for the notational analysis of rugby union (Williams, 1998). This software captured a number of game actions as the game progressed in the real time of the game. For the purpose of this study, all games were notated from video, but in a real-time environment. The system was tested for reliability using percentage differences for inter- and intra- operator reliability (Hughes et al., 2002). This scored error percentages of less than 5%, which was considered acceptable given the analytical goals of the study. The data were examined for significant differences using Kruskal-Wallis and was then interrogated further using a post-hoc application of a Mann-Whitney test.

The study found that both match and ball in play time increased significantly. It is suggested that this was largely due to the changes in the rules that were introduced over the period of the research. Differences were found between groups of games, especially between the Northern and Southern Hemisphere teams with regards to the ball in play time. This would indicate that the rule changes have had a more positive effect in the Northern Hemisphere. In addition to differences between groups, it was found that the increase in ball in play time and continuity may have contributed to an increase in the match time. More continuity may mean more action and more injuries, which in turn increased the match time. This may need further investigation in order to correlate the number of injuries and game time.