Answer:
The correct answer is ''insufficient intracellular quantities of ATP due to excessive consumption''
Explanation:
The energy source for the muscle to contract efficiently is adenosine triphosphate (ATP). When ATP is metabolized, energy is obtained. Under normal conditions, the muscle has a sufficient energy reserve to support a limited time of maximum activity. When this reserve is depleted, the body activates other metabolic pathways to achieve more ATP. Glucose is activated first, then carbohydrates, and last - only if the exercise is prolonged - lipids (fats). The muscle, therefore, ends up transforming this ATP into the necessary energy.Whether our body uses more fat or more glucose / glycogen as fuel will depend, above all, on the intensity and duration of physical exercise. The body uses more fat the more gentle and prolonged the exercise; while, the more intense the sport, the more important the need for glycogen will be.Muscle fatigue is the inability or lack of strength to continue doing a certain activity. It happens when the muscles are not strong enough to continue. Specifically, when carrying out a physical activity, the active muscle requires oxygen and energy reserves of glycogen; When the intensity of the activity is increased, this need for oxygen increases, exceeding the levels that the transport system is capable of providing.This situation leads to the active muscle looking for another source of energy, increasing lactic acid which, in turn, it develops a metabolic acidosis that can lead to the breakdown of muscle fiber. ATP is obtained from the oxidative degradation of metabolic substrates such as muscle glycogen, serum glucose, free fatty acids originating from muscles or adipose tissue, being characteristic of muscle fiber, the consumption of ATP, and the production of ADP and Pi, much faster than it regenerates.
