Physical fitness comprises two related concepts: general fitness , and specific fitness . Physical fitness is generally achieved through correct nutrition, exercise, and enough rest.
Definition:
Examples are:
100 m sprint: in a sprint the athlete must be trained to work anaerobically throughout the race.
Marathon: in this case the athlete must be trained to work aerobically and their endurance must be built-up to a maximum.
Soldiers of the United States Army must be able to pass the Army Physical Fitness Test.