Research in the field of exercise biochemistry has led to understanding in a wide range of topics related to sport and exercise nutrition. Critically, knowledge of the factors that may limit cellular metabolism and lead to local muscular fatigue (inability to sustain the intended intensity of effort) have been identified. Understanding these limiting factors has led to the development of numerous nutritional intervention strategies in an attempt to overcome limitations and ultimately improve performance or extend endurance capacity.
An understanding of the impact of exercise intensity and duration on the metabolic demand for adenosine triphosphate (ATP) is key when examining substrate metabolism, when studying the impact of substrate availability/depletion on muscular fatigue, or when devising nutritional strategies for exercise. The metabolic energy demands of jumping and throwing are very different from sprinting, middle distance running or prolonged endurance events. Therefore, different energy systems, and combinations of these energy systems, are utilised to defend ATP concentration within the working skeletal muscle . ATP requirement in the muscle contraction process is primarily driven by ATP hydrolysis by actomyosin ATPase, but a range of other ATPases such as calcium ATPase and sodium/potassium ATPase also have a role in the whole excitation– contraction coupling process.
Therefore, maintaining and defending cellular ATP concentration is vital to delaying the onset of muscle fatigue at many sites in the whole contractile process. Indeed, maintenance of cellular homeostasis is the fundamental principle in the regulation of body functions in human physiology.