Blake is experiencing delayed onset muscle soreness after a long absence from working out. Which principle of fitness explains Blake's condition?

The principle that best explains Blake's condition of experiencing delayed onset muscle soreness (DOMS) after a long absence from working out is the overload principle. This principle states that in order for muscles to grow and gain strength, they must be subjected to greater stress than they are accustomed to. When Blake returns to exercising, he is likely pushing his muscles harder than they have been conditioned to handle due to his absence from physical activity. This increased demand can lead to microtears in the muscle fibers, resulting in the soreness felt after the workout.

The overload principle emphasizes the need for challenges in a training program to elicit improvements in muscle strength and endurance. When the body is not exposed to regular exercise, the muscles and connective tissues may weaken, and when exercised again, the sudden stress can lead to DOMS.

While progression, reversibility, and regression are also important concepts in fitness, they do not precisely relate to the immediate cause of Blake's soreness. Progression relates more to the gradual increase in intensity over time to continue making gains, whereas reversibility refers to the loss of fitness levels when training ceases. Regression generally pertains to the decline in performance due to a lack of training or insufficient stress.