Trends in match concussion incidence and return-to-play time in male professional Rugby Union: A 16-season prospective cohort study.

AIM: To describe trends in the incidence of match concussions and time to return-to-play in professional rugby union. METHODS: Match concussion incidence (injuries per 1000 player-match-hours) and time to return-to-play (mean and median days absence) were recorded in 3006 male professional rugby union players over 16 seasons (2002/03 - 2018/19). RESULTS: From 2002/03 to 2009/10, incidence of concussions was stable at 4.3/1000 player-match-hours. From 2009/10 to 2018/19, there was an increase in concussion incidence, with the highest incidence in 2016/17 at 20.9/1000 player-match-hours (95% CI: 17.9-24.3). Annual prevalence of concussion also increased, suggesting more players were concussed rather than the same players sustaining more concussions. Before the introduction of standardized graduated return-to-play (GRTP) guidelines in 2011, 27% of players returned to play in <6 days. After the introduction of the GRTP, this decreased to 7%, with no players returning in <6 days after 2014/15. Between 2002/03 and 2018/19, incidence of all other injuries remained stable. CONCLUSIONS: From 2009/10 onwards, the incidence of diagnosed concussions increased. Since the introduction of the GRTP, there has been a dramatic reduction in the number of players returning in <6 days.

Does reducing the height of the tackle through law change in elite men's rugby union (The Championship, England) reduce the incidence of concussion? A controlled study in 126 games.

OBJECTIVES: Most concussions in rugby union occur during tackles. We investigated whether legislation to lower maximum tackle height would change tackle behaviour, and reduce concussion incidence rate. METHODS: In an observational evaluation using a prospective cohort design, 12 elite men's teams played in two competitions during the 2018/2019 season. The Championship (90 games) retained standard Laws of Rugby for the tackle; the Championship Cup (36 games) used revised laws-the maximum tackle height was lowered from the line of the shoulders on the ball carrier to the line of the armpits. Videos of tackles were analysed for ball carrier and tackler behaviour. Injury data were collected using standardised methods. RESULTS: In the lowered tackle height setting, there was a significantly lower proportion of tackles; (1) in which ball carriers (rate ratio (RR) 0.83, 95% CI 0.79 to 0.86) and tacklers (RR 0.80, 95% CI 0.76 to 0.84) were upright, (2) in which the tackler's initial contact was to the ball carrier's head or neck (RR 0.70, 95% CI 0.58 to 0.84) and (3) in which initial contact was above the line of the ball carrier's armpit (RR 0.84, 95% CI 0.80 to 0.88). Concussion incidence rate did not differ between conditions (RR 1.31, 95% CI 0.85 to 2.01). Unexpectedly, compared with the standard tackle height setting, tacklers in the lowered tackle height setting were themselves concussed at a higher rate as measured by; (1) incidence (RR 1.90, 95% CI 1.05 to 3.45) and (2) concussions per 1000 tackles (2.09, 95% CI 1.15 to 3.80). CONCLUSIONS: Legislating to lower the height of the tackle meant that tacklers made contact with the ball carrier's head and neck 30% less often. This did not influence concussion incidence rates. Tacklers in the lowered tackle height setting suffered more concussions than did tacklers in the standard tackle height setting.

Descriptive conversion of performance indicators in rugby union.

OBJECTIVES: The primary aim of this study was to examine whether accuracy of rugby union match prediction outcomes differed dependent on the method of data analysis (i.e., isolated vs. descriptively converted or relative data). A secondary aim was to then use the most appropriate method to investigate the performance indicators (PI's) most relevant to match outcome. METHODS: Data was 16 PI's from 127 matches across the 2016-17 English Premiership rugby season. Given the binary outcome (win/lose), a random forest classification model was built using these data sets. Predictive ability of the models was further assessed by predicting outcomes from data sets of 72 matches across the 2017-18 season. RESULTS: The relative data model attained a balanced prediction rate of 80% (95% CI - 75-85%) for 2016-17 data, whereas the isolated data model only achieved 64% (95% CI - 58-70%). In addition, the relative data model correctly predicted 76% (95% CI - 68-84%) of the 2017-18 data, compared with 70% (95% CI - 63-77%) for the isolated data model. From the relative data model, 10 PI's had significant relationships with game outcome; kicks from hand, clean breaks, average carry distance, penalties conceded when the opposition have the ball, turnovers conceded, total metres carried, defenders beaten, ratio of tackles missed to tackles made, total missed tackles, and turnovers won. CONCLUSIONS: Outcomes of Premiership rugby matches are better predicted when relative data sets are utilised. Basic open-field abilities based around an effective kicking game, ball carrying abilities, and not conceding penalties when the opposition are in possession are the most relevant predictors of success.