On-field movements, heart rate responses and perceived exertion of lead referees in Rugby World Cup matches, 2019

Objectives: Quantify the on-field movements, heart rate and perceived exertion (RPE) of lead referees during Rugby World Cup matches. Design: Descriptive, observational. Methods: On-field movements (distance, average speed, high-speed running [>5 m s−1]), heart rate and RPE of 11 lead referees were assessed during 29 Rugby World Cup (Knockout and Pool) matches. Average speed and heart rate were assessed using rolling average methods (1–10 min epochs). Linear mixed models and Cohen’s effect size (d) were used to compare match variables between Pool and Knockout matches. Results: Referees covered on average 6674 ± 566 m (65.8 ± 6.3 m min−1), with 586 ± 290 m in high-speed running. Mean heart rate was 146 ± 9 beats min−1, summated-heart-rate-zones was 235 ± 36 AU, and sRPE load was 577 ± 205 AU. A large reduction (d = 1.40) in high-speed running distance and moderate reductions in average speed over 1 (d = 0.81) and 2 min (d = 0.83) epochs were found during Knockout, compared to Pool matches. Differences between Pool and Knockout matches on other measures of referee movement, heart rate and RPE were trivial Conclusions: This is the first investigation to examine the effect of competition stage on rugby union referees on-field performance. Individual and match contextual factors may explain the reduction in high-speed running during Knockout matches, however more detailed examination of the factors influencing referee performance is required for greater insight into the key performance indicators in rugby union. Nonetheless, these data provide practitioners with knowledge to assist in preparation of rugby union referees for future Rugby World Cup competitions.