Muscle metabolite accumulation following maximal exercise. A comparison between short-term and prolonged kayak performance.

Five elite flatwater kayak paddlers were studied during indoor simulated 500 and 10,000-m races, with performance times of 2 and 45 min, respectively. Muscle biopsies were obtained from the midportion of m. deltoideus immediately pre and post exercise. Concentrations of adenosine triphosphate (ATP), creatine phosphate (CP), glucose, glucose-6-phosphate (G-6-P), glycogen, and lactate were subsequently determined. Short term exercise resulted in statistically significant increases in glucose (P less than 0.001), G-6-P (P less than 0.05) and lactate (P less than 0.01) concentration concomitant with decreased CP (P less than 0.05) and glycogen (P less than 0.01). Following prolonged exercise, a non-significant elevation in glucose and a reduction (P less than 0.01) in glycogen were demonstrated. Evidently the metabolic demands for kayak competitions at 500 and 10,000 m are different. Thus, the energy contribution from glycolytic precursors and the anaerobic component is of greater relative importance in short distances than in exercise of long duration. A generalization of the findings to other athletic events of varying distances is proposed. The present data on arm-exercise is consistent with previous findings obtained in connection with leg exercises.