# Variability in the Load of Professional Basketball Referees during Competition
Some of these methods require specific equipment and proper use, which can disrupt the athlete's routine during competition, making them less engaged as they cannot obtain information without altering the dynamics of sports practice. Therefore, the most used method for analyzing objective IL is heart rate monitoring [13; 27]. It is a measure that allows for the assessment of exercise intensity due to its close relationship with physiological stimulation [28]. It is easy to obtain, cost-effective, and does not disrupt the dynamics of athletes or referees during competition. On the other hand, load can be measured externally. EL has been defined as the mechanical and locomotor stress caused by sports activity [29]. EL can be measured with kinematic variables that analyze displacements and their intensities, as well as neuromuscular variables that assess the effort exerted between the interaction between gravity and game-related agents [30]. In this regard, various objective systems are available for performance analysis. There is video-based tracking [2; 31], where kinematic analysis is performed using mathematical algorithms with a camera system that allows for tracking the game and its participants. Also, there are Global Navigation Satellite Systems (GNSSs) [32] and Local Position Systems (LPSs) with Ultra-Wideband (UWB) technology [33]. For the localization of athletes in GNSSs and LPSs, athletes must carry an inertial measurement unit typically placed in an anatomical harness on their back to record data. In addition, thanks to their radiofrequency antenna system, LPSs with UWB technology allow for the analysis of load variables in indoor sports [34]. Some of these systems provide real-time information with ANT+ technology, allowing for more precise referee control as they determine kinematic variables (distance covered, accelerations, speeds, etc.) and neuromuscular variables (Player Load, Power Metabolic, and Impacts), which accurately assess the load involved in a game in real time [35], as well as the fatigue index produced [36]. The load demands of basketball referees are being studied to develop training programs tailored to competitive reality. Objective internal load (OIL) was evaluated by [PERSON] et al. [37] in a large population of basketball referees during FIBA international competitions. They identified differences in the average heart rate of referees in men's and women's games, as well as based on the category. It was evident that international competitions are more demanding for referees based on gender, level, and phase of the competition. In a similar way, [PERSON] et al. [38] assessed the objective EL neuromuscular (Player Load) of semi-professional referees and identified that the volume and intensity of load were higher in women's games, which were officiated with two referees, compared with men's games, which had three referees. They also highlighted that, during the same period of the season (regular season vs. playoffs), the demands were similar, with differences among quarters and differences in load between different moments of the season and between game quarters. Collecting data on load demands in players and referees is complex during official competitions, as sports organizations restrict the use of inertial devices that may interfere with the players. Therefore, there are limited studies in which referees are equipped with inertial devices using UWB systems for EL data acquisition, especially when monitoring the performance of referees with senior players in high-level professional leagues. In this sense, with a very limited sample size, [PERSON] et al. [39] identified that both the maximum and average heart rate of referees decrease as the quarter of the games progresses, with the difference between the first and fourth quarter being statistically significant. They also observed a decrease in Maximum Speed, with statistically significant differences between the fourth quarter and the other three quarters. These findings contrast with an increase in distance covered.