Assessing Assistant Referees’ Movement Patterns during the First Half of a Professional Soccer Season

Abstract

PURPOSE: To examine North American Professional Soccer assistant referees’ (ARs) movement pattern differences between the first and second halves of games during the first half of a soccer season. METHODS: Forty-seven North American ARs were observed during the first half of the 2014 regular season. Movement patterns were analyzed by a 2-D camera system and transferred from raw data to readily usable data. Standing, walking, jogging, and High-intensity Running (HIR) movement patterns (ie. running and sprinting) were assessed (ie. total distance covered and distance covered while moving in each speed zone) relative to each individual AR’s predetermined maximum running speed. HIR has been reported in prior research as speeds greater than 13 km/h. Because this study utilized relative speed zones, our HIR values corresponded to speeds greater than 50% of the referee’s max speed. Paired samples t-tests were utilized to assess all dependent variables. One-Way ANOVAs were conducted to analyze differences between first and second half values. RESULTS: ARs covered an average total distance of 6170.72 +/- 526.99m per game. Also, the ARs covered the majority (2854.25 +/- 327.56m, or 46.3%) of their total distance in the 21-50% (“jogging”) of max speed range. Standing (p<.001) and walking (p=.001) increased in the second half, whereas jogging, running, and sprinting (p=.018) decreased. HIR accounted for 1212.31m, or 19.6%, of the total distance covered, yet decreased from 619.17m in the first half to 592.99m in the second half. Total distances covered were 3085.10m and 3086.31m in the first and second half, respectively. CONCLUSIONS: These professional North American Professional Soccer ARs appear to travel similar distances as their international counterparts. Despite the almost identical total distance covered in each half, it appears the referees covered less distances at higher speeds, suggesting the ARs may not have been physically recovered enough (i.e. due to demands of the first half, stress of traveling to the game, daily life stress, etc.) to meet the demands of the second half of the match. Since the primary role of the AR is to observe offside infractions, future research should be conducted in North America to determine where these ARs are specifically located on the sideline when an offside decision is to be decided.