Physiological Responses during a Professional Rugby League Match

Rugby league is a 13-a-side game characterised by prolonged high intensity, intermittent exercise with regular physical impacts. The purpose of the present study was to examine the estimated energy expenditure, blood lactate concentration and heart rate (HR) during a competitive match. Seventeen professional rugby league players (age: 23.9 ± 4.1 years; V02max: 56.9 ± 3.6 mL-kg-1•min-1; height: 181.7 ± 6.1 cm; body mass: 90.2 ± 9 .. 6 kg (mean ± SD)) volunteered to participate in the study. Heart rates were 'recorded continuously via Polar Vantage NV recordable HR monitors throughout the entire match. Blood lactate samples (n=l02) were measured pre-game, post-warm up, during stoppages in play of each half, at half time and immediately after the game. The estimated energy expenditure during a game calculated from the HR-V02 relationship determined infield-testing was approximately 7.9 MJ. Mean blood lactate concentration was 7.2 ± 2.5 mmol •D1, with concentrations for the first and second halves of 8.4 ± 1.8 mmol•D1 and 5.9 ± 2.5 mmol•D1, respectively. The mean team HR (n=l5) recorded during the first and second halves were 167 ± 8 bpm and 164 ± 12 bpm, respectively, with the mean match intensity being 81.1 ± 5.8% of HRmax. Most of time spent in the game was spent in either moderate (39.7 ± 12.5% between 70-85% HRmax) or high intensity (44.4 ± 15.9% above 85% HRmax) activities. Both match lactates and match heart rates were significantly lower during the second half (P