Which principle of training emphasizes the need to increase workload over time?

The principle of training that emphasizes the need to increase workload over time is indeed the principle of overload. This principle is fundamental to achieving progress in physical fitness. Overload refers to the concept that in order to improve strength, endurance, or overall fitness, one must continually challenge the body by increasing the intensity, duration, frequency, or type of exercise. By applying a greater-than-normal load, the body adapts to this increased demand, leading to physiological improvements such as muscle growth, enhanced endurance, and increased metabolic efficiency.

For example, if an individual lifts weights, they will need to gradually increase the amount of weight lifted, the number of repetitions performed, or the number of sets in order to continue seeing progress and avoid plateaus. This principle is crucial for anyone looking to improve their fitness levels, as it prevents stagnation and helps in maintaining motivation toward achieving fitness goals.