Muscle glycogen and diet in elite soccer players

The top players in an elite soccer team volunteered as subjects in a study to determine intramuscular glycogen concentrations after a regular season match, and whether optimal glycogen levels could be re-attained prior to the team's next match. Fifteen players were biopsied in the M. vastus lateralis following a regular season game (Day I). Of these, eight were biopsied 24 h later in the evening of a free day during which no training session was held (Day II), and again 24 h later after a very light training session (Day III). Muscle glycogen concentrations for the eight players averaged (+/- SD) 45.9 +/- 7.9, 68.9 +/- 2.7, and 72.8 +/- 8.3 mmol glucose units x kg-1 wet muscle weight on Day I, Day II, and Day III respectively. Dietary records were analysed during a week of peak, season competition and training. The average daily total energy consumption and total quantity of carbohydrates consumed were less than what is normally consumed by athletes in similar sports. The inability of the players to maintain even normal, resting levels of muscle glycogen is probably related to their dietary practices.