Validity and reliability of the physiological and perceptual responses elicited during a novel treadmill-based Soccer Referee Simulation (SRS)

Purpose: This study explored the validity and reliability of the physiological and perceptual responses elicited during a novel treadmill-based Soccer Referee Simulation (SRS).Methods: Following the collection of baseline measures and habituation procedures, eight sub-elite soccer referees completed a single trial of the SRS whereby measures of heart rate (HR), oxygen uptake (V̇O2), blood lactate concentrations ([La-]b), and differential ratings of perceived exertion (RPE) were obtained. Referees’ HR responses were also monitored during a series of competitive matches (5 match observations per referee). For the reliability aspect of the investigation, eight well-trained males with soccer playing experience and a comparable physiological profile were initially habituated, and thereafter completed three separate trials of the SRS during which the reliability of the selected outcome variables were ascertained. Trials were separated by 3-7 days and performed under standardised conditions. Results: No differences were evidenced between the SRS and match play in relation to measures of mean HR (P=0.444; ES=0.29), peak HR (P=0.074; ES=0.74), or HR-based training impulse (P=0.498; ES=0.25). Additionally, no systematic differences were detected between reliability trials for any of the measured outcome variables (P≥0.293), whilst good levels of reliability were observed for measures of mean HR (ICC=0.94; CV=3.1%), peak HR (ICC=0.93; CV=2.2%), HR-based training impulse (ICC=0.95; CV=10.0%), mean V̇O2 (ICC=0.95; CV=2.6%); [La-]b (ICC≥0.89; CV≤11.5%), and differential RPE (ICC≥0.94; CV≤15.1%). Conclusion: The SRS represents a valid and reliable protocol that closely replicates the physiological and decision-making demands of soccer refereeing.