Introduction: Global positioning system (GPS) technology provides accurate, real-time movement pattern analysis. GPS will improve understanding of the movement characteristics of players during professional rugby union matchplay. Methods: 19 Professional rugby players were tracked using GPS during 24 matches during the 2013 rugby season. Players were grouped as (1) backs or forwards and (2) tight forwards, loose forwards, scrumhalves, inside backs or outside backs. Movements were categorized as walking (0-2m.s-1), jogging (2-4m.s-1), striding (4-6m.s-1) and sprinting (>6m.s-1). Walking and jogging were classified as low intensity and striding and sprinting as high intensity movement zones. An inbuilt tri-axial accelerometer quantified impacts. Pacing effects were determined by comparing 1st and 2nd half movement patterns and whole game players to substitutes. Results: There was no difference between forwards and backs in relative distance covered or impact variables. Backs reached higher maximum speeds than forwards (Backs 8.8 ± 1.1 vs. Forwards 7.6 ± 1.3 m.s-1, ES = 1.0), and covered more distance than forwards in high intensity speed zones (forwards 10 ± 5 vs. backs 12 ± 4 m.min-1, ES = 0.6). Outside backs were the fastest positional group (9.4 ± 0.9 m.s-1, ES = 0.4-2.2), while tight forwards covered the most distance in low intensity zones (57 ± 5m.min-1, ES = 0.4–1.8) Loose forwards and inside backs exhibited similar movement patterns. Relative distance (m.min-1) increased in the second half for whole game players (7 &p lusmn; 9%). High-intensity running distance decreased in the second half for forwards (1st 10.0 ± 5.0 vs. 2nd 8.6 ± 3.8 m.min-1), but increased for backs (1st 10.6 ± 3.2 vs. 2nd 11.4 ± 2.5 m.min-1). Substitutes demonstrated increased relative jogging (Start 20 ± 5 vs. Sub 24 ± 6 m.min-1) and striding (Start 8 ± 2 vs. Sub 11 ± 6 m.min-1) distance versus whole game players. Conclusions: There are notable differences in the movement of professional rugby union players in different positions. Fatigue results in reduced high-intensity running distance and this effect can be managed through the use of substitutes
