What type of training is characterized by varying the intensity and volume of workouts?

The correct answer, which describes training characterized by varying the intensity and volume of workouts, is interval training. This type of training involves alternating periods of high-intensity activity with periods of lower intensity or rest. By varying these intensities, interval training effectively stimulates different energy systems and promotes greater cardiovascular and muscular adaptations.

This approach allows for more efficient workouts as it can significantly enhance aerobic and anaerobic capacities in a shorter amount of time compared to steady-state training, which maintains a consistent intensity throughout the exercise session. Additionally, interval training can help improve stamina and endurance while also providing metabolic benefits that support fat loss and muscle retention.

In contrast, progressive overload refers to the gradual increase of stress placed upon the body during training, which does not necessarily involve varying intensity and volume within a single workout. Steady-state training involves maintaining a steady level of exertion throughout the workout, lacking the variability of intensity. High-intensity training typically refers to exercises performed at a high level of intensity but does not inherently involve the fluctuating intensity that defines interval training.