Which of the following is a characteristic of interval training?

Interval training is defined by its structure involving alternating periods of high-intensity effort with periods of rest or lower-intensity exercise. This method allows the body to exert maximum effort during the high-intensity segments, improving both aerobic and anaerobic fitness levels. The inclusion of intermittent bursts of high effort is what distinguishes interval training from continuous or steady-state training, where the intensity remains constant and lower over a longer duration.

The effectiveness of interval training lies in its ability to enhance cardiovascular fitness and increase metabolic rate, making it a popular choice for improving overall fitness in a shorter amount of time. The periods of rest or lower intensity serve to allow partial recovery, making it possible to sustain a high intensity over multiple intervals, which is not achievable in continuous low-intensity training or forms of exercise that don't incorporate rest.