The Effect of the Video Assistant Referee System Implementation on Match Physical Demands in the Spanish LaLiga.

The present study aimed to analyze the influence of the Video Assistant Referee (VAR) on match physical demands in the top Spanish professional football league. Match physical demand data from all the matches for two seasons (2017/2018 and 2018/2019) in the First Spanish Division ( n = 1454) were recorded using an optical tracking system (ChyronHego ® ). Total distance, relative total distance covered per minute, distance covered between 14-21 km·h -1 , distance covered between 21-24 km·h -1 , and distance covered at more than 24 km·h -1 were analyzed; also, the number of sprints between 21-24 km·h -1 and more than 24 km·h -1 were taken into consideration. The times the VAR intervened in matches were also taken into account. Results showed that total distance and relative total distance significantly decreased in seasons with VAR compared to seasons without VAR. Finally, distance covered between 21-24 km·h -1 , distance covered at more than 24 km·h -1 , and the number of high-intensity efforts between 21-24 km·h -1 and more than 24 km·h -1 increased in seasons with VAR compared to seasons without VAR, but the differences were nonsignificant. Thus, these findings help practitioners to better understand the effects of the VAR system on professional football physical performance and to identify strategies to reproduce competition demands.