The Reproducibility and External Validity of a Modified Rugby League Movement-Simulation Protocol for Interchange...

To assess the reliability and external validity of a rugby league movement-simulation protocol for interchange players (RLMSP-i) that was adapted to include physical contact between participants.

A total of 18 rugby players performed 2 trials of a modified RLMSP-i, 7 d apart. The simulation was conducted outdoors on artificial turf with movement speeds controlled using an audio signal. Microtechnology was used to measure locomotive and accelerometer (ie, PlayerLoad™) metrics for both bouts (∼23 min each) alongside heart rate (HR) and rating of perceived exertion (RPE).

Reported for each bout, total distance (102 [3] m·min-1 and 101 [3] m·min-1), low-speed distance (77 [3] m·min-1 and 79 [4] m·min-1), high-speed distance (25 [3] m·min-1 and 22 [4] m·min-1), PlayerLoad (10 [1] AU·min-1 and 10 [1] AU·min-1), PlayerLoad slow (3.2 [0.6] AU·min-1 and 3.2 [0.6] AU·min-1), 2-dimensional PlayerLoad (6.0 [0.9] AU·min-1 and 5.7 [0.8] AU·min-1), and HR (86 [5]%HRmax and 84 [6]%HRmax) were similar to match play. The coefficient of variation (CV%) for locomotive metrics ranged from 1.3% to 14.4%, accelerometer CV% 4.4% to 10.0%, and internal load 4.8% to 13.7%. All variables presented a CV% less than the calculated moderate change during 1 or both bouts of the simulation except high-speed distance, percentage of the participant's peak HR, and RPE.

The modified RLMSP-i offers a reliable simulation to investigate influences of training and nutrition interventions on the movement and collision activities of rugby league interchange players.