Principles of Overload, Specificity and Progression

Overload is necessary in order to develop fitness in all exercise-related fitness components: cardiorespiratory (aerobic) endurance, muscular strength, muscular endurance and flexibility. According to the principle of overload, a person must work (load) the body in a higher manner than normal in order to improve fitness. For improved cardiorespiratory endurance via walking, for example, this means walking faster or farther or more times a week than usual. Muscular strength and muscular endurance overload means contracting the body’s muscles for a longer period of time, or more frequently during the week, or adding weight to the number of repetitions performed. Flexibility improvements require stretching more often or holding individual stretches for longer periods of time, or stretching beyond the usual point of flexion or extension.