High speed sprinting is a key feature of decisive game situations and during the most important games of the competitive season. In a study analyzing goal situations in professional soccer, 45% of all goals were preceded by a straight sprint from the scoring player1. In addition, elite Australian Rules football players double the number of maximum accelerations in finals compared to regular season games 2. Not surprisingly, in a time-motion study in basketball, researchers found that basketball requires a high frequency of linear sprints, short sprints, and repeat sprints. 3
It has been demonstrated in several studies that glycogen improves repeat sprint performance 4,5,6. However, what role does glycogen play during a single sprint? In a study of muscle metabolism during sprint running, glycogen contributed approximately 50% of the ATP within the muscle during a single 6-second sprint7. Combining this result with findings that muscle glycogen concentrations of lower than approximately 200 mmol/kg dry weight have been shown to significantly decrease the glycolytic rate 8,9and that glycogen can be significantly reduced following team games 10,11,12,13, resistance training14, and sports practice in basketball and football, it becomes clear that high muscle glycogen is desirable for athletes in team sports, such as soccer, rugby, Australian Rules football, American football, and basketball.
As mentioned above, the glycolytic rate is reduced when glycogen reaches a low value of 200 mmol/kg dry weight (approximately 30 MuscleSound score). In studies demonstrating improved intermittent sprint performance in high versus low glycogen groups, the high glycogen group typically has muscle glycogen concentrations of approximately 340 – 400 mmol/kg dry weight, which correspond to a MuscleSound glycogen score of approximately 60. In consideration of the above, it seems that athletes and their staff should work to achieve pre-training/competition MuscleSound scores of approximately 60, while trying to prevent scores from dropping beyond 40 by the end of the training/competition.
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