Final answer:
The foundational or base training phase involves a mix of short vigorous and longer medium physical exercises to build up initial conditioning. This phase is essential for preparing the body for more intense training and preventing injuries.
Step-by-step explanation:
The training phase designed to establish an initial base of conditioning to increase tolerance for more intense training is typically referred to as the foundational or base training phase. In this phase, a pattern of physical exercise that involves short periods of vigorous muscular work and longer periods of medium (and varied) muscular work is used to gradually build up an individual's endurance, strength, and overall fitness level. This is critical before moving on to more intense and specific training sessions, as it prepares the body to handle increased stress and helps in preventing potential injuries.