Lower limb explosive power and dynamic stability in soccer referees and assistant referees

Background: Elite referees make more than 1,400 changes of action and up to 500 changes of direction in a match, which places a high demand on the explosive power of lower limbs. Lower limb injuries are a common problem for soccer referees and have a negative impact on their performance in a match. The purpose of the study was to assess the explosive power and dynamic stability of soccer referees from the viewpoint of refereeing function. Methods: The research sample consisted of 26 soccer referees, including 13 head referees and 13 assistant referees. The following jump tests were administered to determine the referees’ lower limb explosive power: the countermovement jump test (CMJ), the countermovement jump test with free arms (CMJ FA), the squat jump (SJ), and a 10-second vertical jump test. The level of dynamic stability was diagnosed by the Y Balance test. Results: Compared to assistant referees, head referees reached higher levels of explosive power in all measured parameters but the differences were not statistically significant. For the level of dynamic stability, we observed significant differences in the composite score and % lower limb length in favor of the referees in the posteromedial and posterolateral directions for the left and right legs. Conclusions: The greatest differences were found in dynamic stability, specifically in the composite score and % lower limb length in the posteromedial and posterolateral direction. The differences may be caused by typical movement patterns associated with these two adjudicatory roles. We recommend the inclusion of compensatory exercises in the training of assistant referees.