Levels of Stress in Volleyball Referees During Official Matches—The Influence of the Referee Role and Level of Competition

Volleyball referees, as athletes and staff members, are exposed to different stress levels which can be determined by measuring pre- and post-match levels of salivary cortisol (C) and alpha-amylase (AA). This study aimed to determine the dynamics of stress biomarkers in referees during official volleyball matches and the connection to the roles or level of competition. The participants in this study were nine international volleyball referees (three females and six males) with a mean chronological age of 48.23 ± 2.31 years. In this study, saliva samples were collected during 24 official matches during the European championship for senior women's teams (Eurovolley 2021). The AA activity and C concentrations were determined from saliva samples. When the referees' roles were assessed in line with their duties, the first referees' salivary C levels showed a significant increase between the pre- and post-match measurements (<i>p</i> = 0.01), while in the second referees remained low. The reserve and challenge referees demonstrated a significant drop in their C concentrations (<i>p</i> = 0.00 and <i>p</i> = 0.02, respectively). Additionally, when assessing AA which accounts for the responsibilities of referees and the intensity of competition, the first (<i>p</i> = 0.06 and <i>p</i> = 0.07) and second referees (<i>p</i> = 0.01 and <i>p</i> = 0.00) showed an increase between the pre- and post-match measurements, respectively. At the same time, the AA activity did not show any significant change concerning the reserve and challenge referees. Our results indicate that referees' roles and the level of competition may cause higher responses in "active referee roles"-mainly the first and second referees-while reserve and challenge referees showed no increase or even a decrease in the measured biomarkers. The observed changes in the stress markers can be explained by psychological or emotional effects and are dependent on the level of competition and the role referees are fulfilling.