Muscle metabolism and fatigue during simulated ice hockey match-play in elite players

Purpose: The present study investigated muscle metabolism and fatigue during simulated elite male ice hockey match-play.

Methods: Thirty U20 male national team players completed an experimental game comprising three periods of 8x1-min shifts separated by 2-min recovery intervals. Two vastus lateralis biopsies were obtained either during the game (n = 7) or pre- and post-game (n = 6). Venous blood samples were drawn pre-game and at the end of the first and last period (n = 14). Activity pattern and physiological responses were continuously monitored using local positioning system and heart rate recordings. Further, repeated-sprint ability was tested pre-game and after each period.

Results: Total distance covered was 5980±199 m with almost half the distance covered at high skating speeds (>17 km·h^-1). Average and peak on-ice heart rate was 84±2 and 97±2% of maximum heart rate, respectively. Muscle lactate increased (P≤0.05) more than 5- and 3-fold, while muscle pH decreased (P≤0.05) from 7.31±0.04 pre-game to 6.99±0.07 and 7.13±0.11 during the first and last period, respectively. Muscle glycogen decreased by 53% post-game (P≤0.05) with ~65% of fast- and slow-twitch fibers depleted of glycogen. Blood lactate increased 6-fold (P≤0.05), while plasma free fatty acid levels increased 1.5- and 3-fold (P≤0.05) after the first and last period. Repeated-sprint ability was impaired (~3%; P≤0.05) post-game concomitant with a ~10% decrease in the number of accelerations and decelerations during the second and last period (P≤0.05).

Conclusion: Our findings demonstrate that a simulated ice hockey match-play scenario encompasses a high on-ice heart rate response and glycolytic loading resulting in a marked degradation of muscle glycogen, particularly in specific sub-groups of fibers. This may be of importance both for fatigue in the final stages of a game and for subsequent recovery.