Final answer:
The training principle of variety helps prevent plateaus and injuries by introducing new challenges to the body avoiding repetitive strain, and enabling comprehensive physical development.
Step-by-step explanation:
The application of the training principle variety will prevent an individual from hitting a plateau or worse, getting injured. By incorporating different exercises, cross-training, or altering intensity and duration muscles and body systems face new challenges reducing the risk of overuse injuries that can occur with repetitive motions and preventing the body from adapting too fully to one set of stressors, which could lead to plateaus.
Variety in a training program keeps the body guessing and allows for comprehensive development of strength, endurance, and flexibility.