Chapter 23:
General Training Principles
There are a number of general exercise principles that apply to all forms of exercise. These
include progressive overload and specificity. Both are discussed below. Additionally, the FITT
equation, which is used to determine the various components of an exercise program is also
discussed.
Section 1: Progressive overload and SAID
Progressive overload
The most basic principle of exercise training is progressive overload which means that the
body must be overloaded for fitness to increase. The specific type of overload used will depend on
the type of training being done. Aerobic fitness can be improved by performing longer duration
exercise or covering the same distance in less time. Progressive overload can be applied to
interval training by completing more intervals, or working at a higher intensity. Increases in
strength and size can be attained by increasing the weight being lifted, lifting the same weight for
more repetitions, performing more or different exercises,etc. Regardless of the specific nature of
adaptation, the body tends to have a general mode of adaptation (1). This is sometimes referred
to as the General Adaptation Syndrome or G.A.S.
The G.A.S. involves three steps:
- Alarm: Following a stress to the body (i.e. a workout), there is a temporary decline in
performance, - Resistance: the alarm stage is followed by super compensation in the system which was
trained (muscle, nervous system, aerobic system), - Exhaustion: If inadequate rest or nutrients are given or the stress occurs too frequently, the
body’s performance capacity will decrease, called the exhaustion stage (more commonly called
overtraining).
Specificity and the SAID Principle
The adaptations seen in training are specific to the type of training done. This is
sometimes called Specific Adaptations to Imposed Demands or SAID by exercise physiologists.
For example, aerobic training improves the body’s ability to perform aerobically (by making
muscle fibers smaller and more oxidative), but does not improve strength. Strength training
improves the body’s ability to generate strength (by making muscle fibers bigger and more
glycolytic) but does not improve aerobic endurance (2,3).
Another example is the carryover between different exercises. Strength gains in one