The emergence of critical incidents in Rugby Union matches using Markov chain analysis

During a rugby match, teams are continually trying to cause instabilities of different magnitudes on each other. Once a perturbation occurs, a phase transition emerges. Markov chain analysis has the potential to investigate emerging patterns in rugby union. This study examined the probability of a critical incident (CI; penalties and tries) occurring during Rugby Union matches, and whether differences would exist between winning and losing. The Markov chain analysis was used to identify the probability of a transition from a game state to a further state, due to the analysis of the preceding state. A game phase was defined as a technical and tactical match action which occurred between two consecutive advantage lines. Contingency tables were assembled from 280 phases registered during 11 matches of Brazilian Rugby Union XV A Series Championship. The results showed that previous technical and tactical actions made from rucks had the highest probability of generating a transition phase leading to a CI. The results suggest that the winning teams adopt a more flexible approach to the environmental changes that occur throughout a game and demonstrated more flexibility during transitional state occurrences, with higher variability in technical and tactical actions related to a previous game phase.