FITT Principle
The FITT Principle provides a framework for developing a program. Each aspect of the FITT Principle (frequency, intensity, time, and type) must be considered and should complement each other. These four components should complement each other to give you a comfortable exercise session. Remember, exercise should challenge you and leave you feeling refreshed, not like you have been run over.
F: Frequency is the number of times you exercise each week.
I: Intensity is how hard you are working while you are exercising.
T: Time is the total amount of time that is spent exercising in one session.
T: Type is the type of exercise you are doing.