A landmark study by Harris et al. (1992) quantified creatine’s role in muscle energy metabolism with striking precision: phosphocreatine supplies approximately 70% of ATP regeneration during the first three seconds of maximal muscle contraction. This finding fundamentally reshapes how we understand creatine supplementation. The phosphocreatine system operates as the dominant energy source only during very brief, high-intensity efforts—a window that closes rapidly. By 10 to 30 seconds of sustained contraction, phosphocreatine contribution drops to 40–50%, and beyond 30 seconds, it declines further to approximately 15% as glycolytic and oxidative metabolism assume primary roles. This temporal specificity explains why creatine supplementation reliably enhances sprint and power performance but provides minimal benefit for endurance activities lasting beyond 30 seconds. Read the full article on GMJ Newsroom.
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