title: Energetic Demands of Interchange and Full-Match Rugby League Players.
abstract: Cummins, CJ, Gray, AJ, Shorter, KA, Halaki, M, and Orr, R. Energetic demands of interchange and full-match rugby league players. J Strength Cond Res 32(12): 3456-3464, 2018-The purpose of this study was to describe and compare the metabolic demands of rugby league for interchange and full-match players in relation to positional groups. Eighteen elite rugby league players were recruited. A time-motion model was used to estimate the energy expenditure and metabolic demands of rugby league match-play using Global Positioning System (GPS) technology. This approach uses players' GPS velocity-time curves to examine running velocity. Players were categorized into positional groups (outside backs, adjustables, wide-running, and hit-up forwards) and then further categorized into full-match or interchange players. Compared with their full-match counterparts, interchange wide-running forwards expended greater energy (43.1 ± 6.1 vs. 28.6 ± 7.5 kJ·kg, p ≤ 0.001, effect size [ES] = -2.38) and produced a higher anaerobic index (p = 0.016, ES = 0.56) and mean power (7.4%, p = 0.003, ES = 0.66) per match. Full-match adjustables expended 94.8% more energy (p ≤ 0.001, ES = -2.3) and performed more moderate accelerations (10.1%, p = 0.014, ES = -0.57) and decelerations (7.6%, p = 0.017, ES = -0.8), than their interchange counterparts. Outside backs did not interchange and hit-up forwards rarely (n = 2) played an entire match. Differing metabolic demands were identified for interchange and full-match players across positional groups, suggesting position-specific conditioning drills are required to model the energetic demands of match-play.
authors.affiliation: Exercise and Sports Science, Faculty of Health Sciences, The University of Sydney, Sydney, NSW, Australia.
authors.forename: Cloe J
authors.initials: CJ
authors.lastname: Cummins
authors.affiliation: School of Science and Technology, The University of New England, Armidale, NSW, Australia.
authors.forename: Adrian J
authors.initials: AJ
authors.lastname: Gray
authors.affiliation: School of Science and Technology, The University of New England, Armidale, NSW, Australia.
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Shorter
authors.affiliation: Exercise and Sports Science, Faculty of Health Sciences, The University of Sydney, Sydney, NSW, Australia.
authors.forename: Mark
authors.initials: M
authors.lastname: Halaki
authors.affiliation: Exercise and Sports Science, Faculty of Health Sciences, The University of Sydney, Sydney, NSW, Australia.
authors.forename: Rhonda
authors.initials: R
authors.lastname: Orr
mesh_terms: D000054:Acceleration; D000328:Adult; D054874:Athletic Performance; D003654:Deceleration; D004734:Energy Metabolism; D005538:Football / Q000502:physiology*; D040362:Geographic Information Systems; D006801:Humans; D008297:Male; D055815:Young Adult