Studies employing muscle biopsy sampling immediately following high- intensity exercise have demonstrated that after 30 s of sprinting 80% of the from anaerobic sources more detail, these studies have revealed that intense exercise durations have resulted in ATP, PCr, muscle glycogen being depleted by 9%, 35%, and 17 respectively, whilst 30 seconds of sprinting the reductions are 44%, 66%, and 30% respectively Fatigue, which may be defined as the inability to sustain the necessary cise intensity associated with high-intensity exercise is most often considered t be due to lactic acid accumulation and the associated increase in acidity and reduction in pH due to H ions. This is because lactic acid dissociates into lactate ions and hydrogen ions and it is the hydrogen ions that cause the decrease in