The effects of carbohydrate (CHO) loading on physical characteristics including muscle fiber distribution, muscle glycogen concentration, and physical performance were studied in two top Swedish ice hockey teams. Players were randomly allocated to two groups: those consuming a CHO-enriched diet (CHO group) and those consuming a mixed diet (controls). Biopsies from the vastus lateralis muscle were taken three times: after Game 1, before Game 2, and after Game 2. Muscle fiber distribution averaged 50 ± 2% slow twitch fibers (mean ± 1SEM). Muscle glycogen concentrations (measured in mmol glucose units · kg−1 wet muscle) were as follows: after Game 1, 43 ± 4 (ail players); before Game 2,99 ± 7 (CHO group) and 81 ± 7 (controls); and after Game 2, 46 ± 6 (CHO group) and 44 ± 5 (controls). Distance skated, number of shifts skated, amount of time skated within shifts, and skating speed improved with CHO loading. It was concluded that individual differences in performance could be related to muscle glycogen metabolism.
C. Åkermark was at the time of the study with the Department of Orthopedic Surgery, Huddinge Hospital, Karolinska Institute, Stockholm, Sweden. I. Jacobs was with the Department of Clinical Physiology, Karolinska Institute, at the time of the study and is now with the Defence and Civil Institute of Environmental Medicine, Downsview, ON, Canada M3M 3B9. M. Rasmusson is with the Department of Clinical Chemistry, Lund University, Lund, Sweden. J. Karlsson was with the Department of Clinical Physiology, Karolinska Institute.