Variation
refers to the manipulation of specific training variables such as volume, intensity, exercise selection, frequency of training, rest interval and speed of movement. The application of appropriate training variation is essential when one is attempting to ensure long-term adaptation.

The best way to apply training variation is through use of the principals of periodization, which refers to the logical phasic manipulation of training factors to optimize specific training outcomes at specific time points. If appropriate training variation is not incorporated in the program, the rate of improvement will plateau or decrease, resulting in what is termed as “monotonous program overtraining”.

The variation in a resistance training plan should not be haphazard, and the sequencing of training factors should be appropriate.