Before discussing the contraction process itself, let us look first at how muscle fibers obtain the energy they need to contract. The direct source of energy for muscle contraction is ATP. ATP, however, is not stored in large amounts in muscle fibers and is depleted in a few seconds.
The secondary energy sources are creatine phosphate […]

Multiple studies have now shown that people who maintain appropriate body fitness, using judicious regimens of exercise and weight control, have the additional benefit of prolonged life. Especially between the ages of 50 and 70, studies have shown mortality to be three times less in the most fit people than in the least fit. But […]

Without belaboring this issue, let us list some of the effects of drugs in athletics. First, caffeine is believed by some to increase athletic performance. In one experiment on a marathon runner, running time for the marathon was reduced by 7 per cent by judicious use of caffeine in amounts similar to those found in […]

In addition to the large usage of carbohydrates by the muscles during exercise, especially during the early stages of exercise, muscles use large amounts of fat for energy in the form of fatty acids and acetoacetic acid, and they use to a much less extent proteins in the form of amino acids. In fact, even […]

Phosphocreatine (also called creatine phosphate) is another chemical compound that has a high-energy phosphate bond, with the following formula:
Creatine ~ PO3-
This can decompose to creatine and phosphate ion, as shown to the left in Figure 84–1, and in doing so release large amounts of energy. In fact, the high-energy phosphate bond of phosphocreatine has more […]

The final common determinant of success in athletic events is what the muscles can do for you—what strength they can give when it is needed, what power they can achieve in the performance of work, and how long they can continue their activity.
The strength of a muscle is determined mainly by its size, with a […]

There are few stresses to which the body is exposed that even nearly approach the extreme stresses of heavy exercise. In fact, if some of the extremes of exercise were continued for even moderately prolonged periods, they might be lethal. Therefore, in the main, sports physiology is a discussion of the ultimate limits to which […]