The experiments in this thesis were designed to investigate the factors influencing the metabolism of purine nucleotides in human skeletal muscle, plasma and urine. Study one investigated the influence of the number of intermittent sprint bouts and the subsequent accumulation of plasma purines and urinary purine excretion. Study two investigated the influence of sprint training on urinary purine loss following intense exercise. Study three examined the influence of allopurinol on urinary purine loss after repeated sprint exercise in humans. The final study examined the combined effects of allopurinol and sprint training on purine nucleotide metabolism in humans at rest.