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Chapter

Cover The Biochemical Basis of Sports Performance

The sprinter  

This chapter examines anaerobic metabolism. The sprinter has to sustain a very high-power output over a relatively short period of time. As the intramuscular supply of adenosine triphosphate (ATP) is sufficient to last only about two seconds, there is a pressing need to resynthesize ATP extremely quickly, and this is achieved by the breakdown of intramuscular stores of phosphocreatine and the rapid activation of glycolysis. Both of these processes occur without the utilization of oxygen; that is, they are anaerobic means of regenerating ATP. However, sprinting is not entirely anaerobic. There is a contribution of carbohydrate oxidation to ATP resynthesis during sprinting that increases as the duration and distance of the sprint increases. The chapter then describes the concept of the cellular energy charge and explains why there is a loss of adenine nucleotides during very high-intensity exercise.

Chapter

Cover The Biochemical Basis of Sports Performance

Middle-distance events  

This chapter evaluates the relative contributions to energy metabolism from phosphocreatine breakdown, anaerobic glycolysis, and carbohydrate oxidation during middle-distance running. Oxidative metabolism makes the major contribution to energy production when the exercise duration exceeds about one to two minutes. However, at least for exercise intensities that can be sustained for less than about ten minutes, the rate at which energy must be supplied to the working muscles exceeds the maximum rate of the oxidative processes. The chapter uses the example of the middle-distance track runner to describe the metabolic processes occurring and to consider the causes of fatigue and potential limitations to performance in events taking place over this time scale. The chapter then looks at the glycolytic pathway and the regulation of glycolysis.