Power in fitness is defined as:

Power in fitness specifically refers to the ability to exert muscular strength quickly. It is a combination of both strength and speed, allowing an athlete to perform explosive movements effectively. For instance, activities like sprinting, jumping, or lifting weights in a rapid manner are all demonstrations of power, as they involve generating maximum force in a short period of time.

The other choices, while related to fitness, do not accurately capture the definition of power. Total endurance speaks to stamina and the ability to sustain prolonged physical activity, which is different from the quick exertion of strength. The volume of air inhaled during exercise relates to respiratory efficiency and oxygen uptake, but it does not pertain to the concept of power. Lastly, the amount of rest taken between workouts is more about recovery and training frequency rather than the expression of power itself. Thus, the definition of power distinctly emphasizes rapid strength exertion rather than endurance, respiratory metrics, or recovery strategies.