Introduction

Rugby Union is a team sport built on physicality, speed, and skill, with Match Officials essential to the integrity and flow of the game. Throughout the years, as the game has become faster and more physically intense, with more physically demanding contests, the demands on Match Officials to maintain high levels of physical performance to keep up with play and interpret and apply the Laws of the game have increased significantly. 

Despite their crucial role in the game, Match Officials have historically received less attention in sports science and performance research compared to players; however, over the past number of years, recent research has begun to address this gap, which can play a crucial role in providing insights for the development of evidence-based conditioning programs that support referee performance (Blair et al., 2018; Bester et al., 2019; Igoe and Browne, 2019).