Answer:
Progression
Explanation:
Progression principle is a term used to describe the strategy of physical training in which the intensity and frequency of physical training increases steadily and regularly, as can be seen in Jerry's training.
This principle is important in physical training because our body tends to get used to a physical exercise that was carried out without auterations over a long period of time. This causes the body to show no improvement and to become physically stagnant.
