Movement and Physiological Demands of Australasian National Rugby League Referees.

Purpose: To evaluate the movement and physiological demands of Australasian National Rugby League (NRL) referees, officiating with a 2-referee (ie, lead and pocket) system, and to compare the demands of the lead and pocket referees.

Methods: Global positioning system devices (10 Hz) were used to obtain 86 data sets (lead, n = 41; pocket, n = 45) on 19 NRL referees. Total distance, relative distance covered, and heart rate per half and across match play were examined within and between referees using t tests. Distance, time, and number of movement "efforts" were examined in 6 velocity classifications (ie, standing <0.5, walking 0.51-2.0, jogging 2.01-4.0, running 4.01-5.5, high-speed running 5.51-7.0, and sprinting >7.0 m/s) using analysis of variance. Cohen d effect sizes are reported.

Results: There were no significant differences between the lead and pocket referees for any movement or physiological variable. There was an overall significant (large, very large) effect for distance (% distance) and time (% time) (P < .001) between velocity classifications for both the lead and pocket referees. Both roles covered the largest distance and number of efforts at velocities of 0.51-2.0 m/s and 2.01-4.0 m/s, which were interspersed with efforts >5.51 m/s.

Conclusions: Findings highlight the intermittent nature of rugby league refereeing but show that there were no differences in the movement and physiological demands of the 2 refereeing roles. Findings are valuable for those responsible for the preparation, training, and conditioning of NRL referees and to ensure that training prepares for and simulates match demands.