Correct Response: B. When an athlete trains, the results of the training are specific to the type of training the athlete performs (the principle of specificity). In this case, the woman has been consistently exercising in a way that would tend to increase her endurance rather than her muscle strength. If she had wanted to increase muscle strength, weight training would have been a more targeted exercise. In athletics, the principle of reversibility (A) refers to the fact that the benefits of training diminish when the athlete stops training for an extended period of time. Because the woman has not taken a break from her training, the principle of reversibility does not apply to this situation. The principle of recuperation (C) relates to the fact that the body needs time to recover physically between periods of training. It does not explain why there has been little change in the strength of the woman's leg muscles. In relation to muscular development, the progression principle (D) states that in order for training to increase muscle strength, the intensity or load of the workout must be above the normal load the muscle can handle. This forces the muscle to become stronger over time so that it can bear the additional load. The principle of progression is not the best explanation of the runner's experience, because the woman was not participating in strength-training activities.
