What does "progressive overload" mean in fitness training?

Progressive overload is a fundamental principle in fitness training that refers to the gradual increase in the intensity or volume of exercise to enhance strength, endurance, and overall fitness levels. This concept is crucial because the body adapts to the stresses placed upon it; if you don't progressively challenge your muscles or cardiovascular system, you may experience a plateau in your fitness gains.

By systematically increasing the demands of your workout—whether through more weight, more repetitions, longer durations, or higher intensity—you stimulate muscle growth, improve cardiovascular fitness, and enhance overall performance. This approach helps to prevent stagnation in one's fitness journey and promotes continual improvement.

The other options do not align with the principle of progressive overload. Maintaining the same intensity does not challenge the body or promote growth, while reducing the duration of exercise undermines the goal of enhancing fitness. Lastly, training without rest periods may lead to fatigue and increased risk of injury, rather than promoting progressive adaptation to exercise stress.