Metabolic Power Demands of Rugby League Match Play

Kempton T., Sirotic A.C., Rampinini E., Coutts A.J.

Purpose: To describe the metabolic demands of rugby league match play for positional groups and compare match distances
obtained from high-speed-running classifications with those derived from high metabolic power. Methods: Global positioning
system (GPS) data were collected from 25 players from a team competing in the National Rugby League competition over 39
matches. Players were classified into positional groups (adjustables, outside backs, hit-up forwards, and wide-running forwards).
The GPS devices provided instantaneous raw velocity data at 5 Hz, which were exported to a customized spreadsheet. The

spreadsheet provided calculations for speed-based distances (eg, total distance; high-speed running, >14.4 km/h; and very-high-
speed running, >18.1 km/h) and metabolic-power variables (eg, energy expenditure; average metabolic power; and high-power

distance, >20 W/kg). Results: The data show that speed-based distances and metabolic power varied between positional groups,
although this was largely related to differences in time spent on field. The distance covered at high running speed was lower
than that obtained from high-power thresholds for all positional groups; however, the difference between the 2 methods was
greatest for hit-up forwards and adjustables. Conclusions: Positional differences existed for all metabolic parameters, although
these are at least partially related to time spent on the field. Higher-speed running may underestimate the demands of match
play when compared with high-power distance—although the degree of difference between the measures varied by position.
The analysis of metabolic power may complement traditional speed-based classifications and improve our understanding of the
demands of rugby league match play.