Individual Fluctuations in Blood Lactate Concentration During an Ice Hockey Game; Differences Between Player Positions.

The main purpose of the current study was to provide an in-depth description of individual player's intra-game physiological responses during an ice hockey game. A secondary aim was to compare these responses between forwards and defensemen. Six elite junior ice hockey players, three forwards and three defensemen, median (interquartile range) 17 (17-17) years, 182 (180-185) cm, and 78 (74-80) kg were recruited to participate in the study. Capillary blood samples were taken following each shift and analyzed for blood lactate concentration (BLC). Heart rate (HR) was registered continuously throughout the game. The game was filmed and shift lengths were determined retrospectively using a time-motion analysis. All players had BLC ranging between 1.8 and 10.7 mmol/L (mean = 5.5 mmol/L), with forwards reaching a significantly higher value than defensive players (F 1, 32 = 75.2, p < 0.0001), a significant effect of time was also observed (F 2, 25 = 6.4, p = 0.0058). During the game, the players accumulated 11:18 ± 5:04 (minutes:seconds) above 90% of their maximal heart rate (HRmax), but the majority of the time was below 80% of HRmax. The fluctuations in BLC and heart rate demonstrate that the intensity is highly variable during games and challenges both aerobic and anaerobic metabolic pathways. The higher BLC of forwards might indicate that they perform more high-intensity work during games than defensive players