Physiological and cognitive performance of Futsal and Football referees

Reduction of referees' physical performance in the second half of the game has been observed in previous research on football referees. There is very little research addressing Futsal referees. The aim of the present thesis was to investigate physiological, physical and cognitive performance of Futsal and football referees in field and laboratory studies.

The 1st experimental study (Chapter 4) analysed the activity profile and physiological demands of 18 Futsal referees and referee decision-making performance at different stages of the match (e.g. 1st vs 2nd half). In addition, it explored relationships between physical fitness/performance on the Fédération Internationale de Football Association (FIFA) fitness tests, activity profile and decision-making performance. The main findings were that total distance and average heart rate were higher in the first compared to second half but lactate and session RPE were similar. The proportion of correct decisions decreased in the second half (1st half, 91.1 ± 14.9% correct vs 2nd half, 73.3 ± 17.4%, p = 0.002). No correlations were evident between FIFA fitness tests and activity profile but the Yo-Yo Intermittent Endurance Test - Level 2 (Yo-Yo IET-2) performance and total distance (clock time) were correlated (r = 0.720, p = 0.019). Further motion analysis studies are needed to collect data for referees and players during the same matches. The present study also suggests that the traditional FIFA fitness test (and 1000 m run) were poor for assessing Futsal referee-specific fitness, and tests that involve intermittent and/or direction changes, such as the Yo-Yo test or Assistant Referee Intermittent Endurance Test (ARIET), may be more appropriate, although further research is needed on the ARIET in this context.

The 2nd experimental study (Chapter 5) examined whether undertaking a 10-min Psychomotor Vigilance test (PVT) before a match would influence referees' cognitive performance, especially decision-making (DM) to determine the suitability of using it in field-based studies involving real matches. The results showed that the PVT did not affect referees' decision-making or cognitive performance. Hence, the 10- min PVT can be safely used with referees before real competition/in the field.

The 3rd experimental study (Chapter 6) assessed referees' performance on the PVT before and after competitive Futsal matches. The findings showed that, despite changes in BRUMS parameters indicative of a fatigue profile, psychomotor performance was improved after a single match (PVT mean reaction time 248.3 ± 26.2 ms pre- vs 239.7 ± 22.4 ms post-match, p = 0.023). It is possible that a more strenuous overall demand would cause different effects, however, the post-match improvement observed here could be used to inform warm-up practices (e.g. optimal duration and intensity) geared towards optimising cognitive performance of referees during matches.

The 4th experimental study (Chapter 7) examined the effect of mental fatigue on referees' physiological responses and cognitive performance during a lab-based intermittent protocol. The main findings were that mental fatigue had a significant negative effect on referees' cognitive performance as assessed by a referee-specific decision-making task (correct decisions, 76.7 ± 7.2% at the beginning of exercise vs 64.6 ± 7.8% at the end, p < 0.001), which did not occur in the control trial. PVT performance was also significantly reduced to a greater extend in the mental fatigue, compared to control, condition. This may have implications for optimising referees' preparation and cognitive performance in real matches, which should be explored further.

Overall this thesis has demonstrated that referee performance decreases in the second half in both Futsal and football referees. Further, it provides evidence that this is influenced by mental fatigue. Further investigations on referees' performance and related factors are warranted, along with interventions directed towards improving performance (cognitive and physical) via reducing mental fatigue.