Abstract
BACKGROUND: There is extensive research investigating the match demands of players in the Australian Football League (AFL). OBJECTIVE: This systematic literature review and meta-regression sought to analyse the evolution of in-game demands in AFL matches from 2005 to 2017, focusing on the relationship between volume and intensity. METHODS: A systematic search of Ovid MEDLINE, Embase, Emcare, Scopus, SPORTDiscus, and Cochrane Library databases was conducted. Included studies examined the physical demands of AFL matches utilising global positioning system (GPS) technology. Meta-regression analysed the shift in reported volume (total distance and total match time) and intensity (metres per minute [m.min(-1)], sprint duration and acceleration) metrics for overall changes, across quarters and positional groups (forwards, nomadics and defenders) from 2005 to 2017 inclusive and for each year between 2005 and 2007, 2007 and 2010, 2010 and 2012, and 2012 and 2015/2017 breakpoints. RESULTS: Distance (p = 0.094), m.min(-1) (p = 0.494), match time (p = 0.591), time over 18 km·h(-1) (p = 0.271), and number of accelerations greater than 4 km·h(-1) (p = 0.498) and 10 km·h(-1) (p = 0.335) in 1 s did not change from 2005 to 2017. From 2005 to 2007 volume decreased (- 6.10 min of match time; p = 0.010) and intensity increased (6.8 m.min(-1) increase; p = 0.023). Volume and intensity increased from 2007 to 2010, evidenced by increases in total distance (302 m; p = 0.039), time over 18 km·h(-1) (0.31 min; p = 0.005), and number of accelerations greater than 4 km·h(-1) (41.1; p = 0.004) and 10 km·h(-1) (3.6; p = 0.005) in 1 s. From 2010 to 2012, intensity decreased, evidenced by reductions in metres per minute (- 4.3; p = 0.022), time over 18 km·h(-1) (- 0.93 min; p < 0.001), and number of accelerations greater than 4 km·h(-1) (- 104.4; p < 0.001) and 10 km·h(-1) (- 8.3; p < 0.001) in 1 s, whilst volume stabilised with no changes in distance (p = 0.068) and match time (p = 0.443). From 2012 to 2015/2017 volume remained stable and intensity increased with time over 18 km·h(-1) (0.27 min; p = 0.008) and number of accelerations greater than 4 km·h(-1) (31.6; p = 0.016) in 1 s increasing. CONCLUSIONS: Changes in volume and intensity of AFL match demands are defined by discrete periods from 2007 to 2010 and 2010 to 2012. The interaction of rule and interpretation changes and coaching strategies play a major role in these evolutionary changes. In turn, modified game styles impact player game demands, training, and selection priorities. Standardisation and uniformity of GPS data reporting is recommended due to inconsistencies in the literature.