Final answer:
The FITT principle component related to the amount of energy required by exercise is Intensity. Intensity indicates the level of effort or how hard the body is working, which directly impacts energy expenditure as represented by the equation E = Pt.
Step-by-step explanation:
The FITT principle refers to Frequency, Intensity, Time, and Type, which are the key factors in developing and managing a fitness plan. When considering the amount of energy exercise requires, the most relevant component of the FITT principle is Intensity. Intensity refers to how hard your body is working during physical activity. Taking into account the relationship E = Pt, where E is energy, P is power, and t is time, we can understand that the amount of energy used during exercise is directly related to the power (or intensity) of the activity and its duration. For instance, a high-intensity workout will require more energy compared to a low-intensity activity, assuming the duration is identical.