Global positioning system (GPS) tracking of athletes in selected sports is a new innovation into obtaining comprehensive data regarding physical output with respect to distance travelled (DT), acceleration, and change of direction. The purpose of this study was to determine selected physical demands of American football players during the course of games and to compare such data by player position. Offensive lineman (OL) (n = 14) and defensive lineman (DL) (n = 9) and offensive wide receivers (WRs) (n = 10) and defensive backs (DBs) (n = 10) were fitted with GPS monitors during games. Collected data included DT, maximum velocity (MV), and acceleration (AC), deceleration (DC) distance at 2 intensities. Results indicated that DBs travelled significantly (p < 0.05) greater distances than OL and WR, but not DL. For MV, DBs and WRs were not significantly different but were significantly different from OL and DL. Also, DL was significantly different than OL. For the most intense acceleration (3-10 m·s-2), WR accelerated significantly further than all other positions and DBs accelerated further than DL and OL. There was not significant difference between DL and OL. For deceleration at the high-intensity measure, significant differences existed among all positions. Underestimation of workload during games could be a factor for the overuse and soft-tissue injuries and more serious injuries. Furthermore, using GPS tracking of similar variables as found in this study may benefit coaches and trainers in many other high-intensity sports.
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