Intensity demands and peak performance of elite soccer referees during match play

Objectives: This study examined the peak physical and physiological (heart rate) performance intensities andassociated decrements in elite soccer referees during match play.Design: Longitudinal study.Methods: Physical performancevariables and heart rate were analyzed during 457 matches across two seasons. Differences between halves, and the rate ofdecline in peak performance intensities across moving average dura-tions of 1-10 minutes were assessed using linear mixed models and power-law analysis, respectively.Results: Large significant differences were observed between halves for mean total distance, mean velocity, mean heart rate, and percentage of maximal heart rate (p <= 0.05; r = 0.51-0.64). Peak intensities (p <= 0.05; r = 0.15- 0.17) and the rate of decline (p < 0.001; r = 0.17-0.37) were significantly higher in the 2nd half compared to the 1st half, for relative total distance, relative high-intensity running and mean velocity. The rate of decline was sig-nificantly greater in the 2nd half than the 1st half for relative distance covered by high-intensity acceleration (>2 m/s-2/min), deceleration (<-2 m/s-2/min), and relative mean heart rate (p < 0.001; r = 0.28-0.61). Elite soccer referees might have experienced transient fatigue during match play, as relative high-intensity running immedi-ately following the most intense 5-minute period significantly declined by 61.2% ( p< 0.001; r = 0.94), and was 16.2% lower than the mean 5-minute period (p < 0.001; r = 0.34).Conclusions: Increased physical and physiological demands during match play, with associated declines in the second half and transient signs of fatigue throughout the match, supports the inclusion of high-intensity interval and endurance training programs to prepare soccer referees for the intensity demands and peak performance outcomes of match play.(c) 2022 The Author(s). Published by Elsevier Ltd on behalf of Sports Medicine Australia. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).