Correct Response: D. The goal of progressive overload is to force the body to adapt to the stress of being challenged above its current state of fitness. This can apply to a variety of characteristics, such as endurance and muscle strength. The only way this is accomplished is by gradually increasing the intensity or duration of exercise sessions. Varying the length of time between exercise sessions (A) is not a strategy that challenges the body beyond its current state of fitness. Consistently allowing little or no rest between exercise sessions (B) does not fit the gradual increase of intensity or duration of exercise sessions called for in progressive overload. In fact, it may be detrimental in that it does not allow the body to recover between exercise sessions. Expanding the variety of exercises (C) without also increasing the intensity and/or duration of the exercises is not an application of the principle of progressive overload.
