Answer:
Reversibility principle of exercise
Step-by-step explanation:
Kendra went on vacation for a week, meaning she stopped exercise for a week, and due to this, her body readjusts to what is demanded (rest) making her unable to run as far as she could before when she resumed training. It is now clear she has lost some of her physical skills and this effect is mostly seen when sprinters mostly lose their muscular endurance before losing other skills when they stop training for some days/weeks/months, and this is an example of the reversibility principle of exercise.