Adaptation
The Principle of Adaptation refers to the way in which the body adjusts to increased or decreased demands. This can be lightly explain why a person is sore at the beginning of an exercise program but is not sore later. The body learns how to be more efficient, thereby utilizing less energy to perform the same amount of work. To continue to optimize how many calories the body uses it is important to schedule changes such as the length of a program, rest between sets, speed and/or the type of exercise performed.
