Final answer:
Periodization in fitness is a method that uses body adaptation and variation to enhance physical performance, requiring the progressive increase of exercise intensity to ensure continual muscle growth and strength.
Step-by-step explanation:
Periodization, or planned fitness training, is a systematic approach to fitness program design that exploits the body's adaptation and variation to optimize physical performance.
This involves a pattern of physical exercise that incorporates both vigorous and medium intensity workouts, altering over short and varied periods to maximize muscle growth, strength, and endurance.
The body adapts to the stress of exercise through physiological changes such as hypertrophy, which is the increase in muscle fiber size, and by increasing the efficiency of energy-producing components within the muscle cells.
When a group of people follows the same workout program, individual outcomes, like weight loss variability, can be attributed to genetic factors such as the proportion of fast-twitch and slow-twitch muscle fibers.
Additionally, the principle of progressive overload is crucial for effective strength training, which means continually increasing the intensity of exercises to challenge the muscles and promote further adaptations.