Explain the FITT principle and when will you use it? The F.I.T.T. Principle is generally applicable to low to moderate training levels and is made up of four elements:-  Frequency,  Intensity,  Type and  Time (or duration). Anyone wanting to improve on their physical fitness could increase one or more of these elements. These 4 elements may be used for both cardiorespiratory and resistance training and can be useful when setting up a routine they can be modified to fit an individual's specific needs. The F.I.T.T. Principle helps you change your programme to help you get in shape and achieve better results and also helps prevent boredom, overuse injuries and weight loss plateaus. Explain the REST/EFFORT balance principle While most