Decision-making accuracy of soccer referees in relation to markers of internal and external load

This study examined the relationships between the decision-making performances of soccer referees and markers of physiological load. Following baseline measurements and habituation procedures, 13 national-level male referees completed a novel Soccer Referee Simulation whilst simultaneously adjudicating on a series of video-based decision-making clips. The correctness of each decision was assessed in relation to the mean heart rate (HR), respiratory rate (RR), minute ventilation (VE), perceptions of breathlessness (RPE-B) and local muscular (RPE-M) exertion and running speeds recorded in the 10-s and 60-s preceding decisions. There was a significant association between decision-making accuracy and the mean HR (p = 0.042; VC = 0.272) and RR (p = 0.024, VC = 0.239) in the 10-s preceding decisions, with significantly more errors observed when HR >= 90% of HRmax (OR, 5.39) and RR >= 80% of RRpeak (OR, 3.34). Decision-making accuracy was also significantly associated with the mean running speeds performed in the 10-s (p = 0.003; VC = 0.320) and 60-s (p = 0.016; VC = 0.253) preceding decisions, with workloads of >= 250 m center dot min-1 associated with an increased occurrence of decisional errors (OR, 3.84). Finally, there was a significant association between decision-making accuracy and RPE-B (p = 0.021; VC = 0.287), with a disproportionate number of errors occurring when RPE-B was rated as "very strong" to "maximal" (OR, 7.19). Collectively, the current data offer novel insights into the detrimental effects that high workloads may have upon the decision-making performances of soccer referees. Such information may be useful in designing combined physical and decision-making training programmes that prepare soccer referees for the periods of match play that prove most problematic to their decision-making. Soccer referees exhibited an increased likelihood of making a decisional error when: (1) HR >= 90% of HRmax; (2) RR >= 80% of RRpeak; (3) RPE-B was rated as "very strong" to "maximal" (75-100 au); and (4) running speeds >= 250 m center dot min-1 were performed in the 10-s prior to a decision. In contrast, the accuracy of the referees' decisions was not related to mean measures of HR, RR, or VE obtained in the 60-s preceding decisions. The relationship between the physiological and decision-making aspects of refereeing performance therefore appears to be a transient one, whereby high internal and external loads experienced immediately prior to infringements may compromise the correctness of the decision. Such information may be used to guide the design and delivery of training programmes aimed at preparing soccer referees for the periods of match play that prove most problematic to their decision-making.