title: Heart rate, blood lactate concentration and estimated energy expenditure in a semi-professional rugby league team during a match: a case study.
abstract: The aim of this study was to examine heart rate, blood lactate concentration and estimated energy expenditure during a competitive rugby league match. Seventeen well-trained rugby league players (age, 23.9 +/- 4.1 years; VO2max, 57.9 +/- 3.6 ml x kg(-1) x min(-1); height, 1.82 +/- 0.06 m; body mass, 90.2 +/- 9.6 kg; mean +/- s) participated in the study. Heart rate was recorded continuously throughout the match using Polar Vantage NV recordable heart rate monitors. Blood lactate samples (n = 102) were taken before the match, after the warm-up, at random stoppages in play, at half time and immediately after the match. Estimated energy expenditure during the match was calculated from the heart rate-VO2 relationship determined in laboratory tests. The mean team heart rate (n = 15) was not significantly different between halves (167 +/- 9 vs 165 +/- 11 beats x min(-1)). Mean match intensity was 81.1 +/- 5.8% VO2max. Mean match blood lactate concentration was 7.2 +/- 2.5 mmol x l(-1), with concentrations for the first half (8.4 +/- 1.8 mmol x l(-1)) being significantly higher than those for the second half (5.9 +/- 2.5 mmol x l(-1)) (P<0.05). Energy expenditure was approximately 7.9 MJ. These results demonstrate that semi-professional rugby league is a highly aerobic game with a considerable anaerobic component requiring high lactate tolerance. Training programmes should reflect these demands placed on players during competitive match-play.
authors.affiliation: School of Leisure, Sport and Tourism, University of Technology, Sydney, Lindfield, NSW, Australia. aaron.coutts@uts.edu.au
authors.forename: Aaron
authors.initials: A
authors.lastname: Coutts
authors.forename: Peter
authors.initials: P
authors.lastname: Reaburn
authors.forename: Grant
authors.initials: G
authors.lastname: Abt
mesh_terms: D000328:Adult; D001315:Australia; D015415:Biomarkers / Q000097:blood; D004734:Energy Metabolism / Q000502:physiology*; D005538:Football / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007773:Lactates / Q000097:blood*; D010807:Physical Endurance / Q000502:physiology
chemical_list: D015415:Biomarkers; D007773:Lactates