Final answer:
The traditional method designed to increase training intensity and decrease volume over time is C) linear periodization, a common approach used to prepare athletes for peak performance.
Step-by-step explanation:
The traditional method of program design which aims to gradually increase the intensity of the training load while simultaneously decreasing volume over a set period of time is linear periodization.
This approach involves incrementally boosting the intensity, which may include lifting heavier weights or running at a faster pace, and often this comes with a corresponding decrease in volume, such as doing fewer repetitions or running fewer miles.
Linear periodization is a staple method used by athletes to prepare for peak performance at the right time, with a typical pattern of physical exercise involving some short periods of vigorous muscular work and longer periods of medium and varied muscular work.