FITT

The FITT principle is a foundational framework in exercise science used to design and adjust training programs. Standing for Frequency, Intensity, Time, and Type, FITT helps practitioners tailor workouts to an individual's goals, abilities, and health status. The concept is widely used by fitness professionals, coaches, and clinical exercise specialists to structure progressive training plans.

Frequency refers to how often a person trains each week. Intensity indicates the effort or load, which may be quantified by heart rate, percentages of one-repetition maximum, or perceived exertion. Time denotes the duration or total amount of exercise per session or week. Type describes the activity category, such as aerobic, resistance, flexibility, or balance training.

In practice, FITT is combined with progression and specificity. Examples: general health guidelines often suggest 150 minutes of moderate-intensity aerobic activity per week plus two or more days of strength training, with sessions lasting 20–60 minutes. To progress, one can increase frequency, lengthen sessions, raise intensity, or switch to a more demanding type. Programs are adjusted for goals (endurance, strength, weight loss) and for individual constraints or medical conditions.

Limitations and variants: FITT is a flexible guideline rather than a strict prescription and should be adapted for safety and personal factors. Some practitioners use FITT-VP, adding Volume (total work) and Pattern (how work is distributed). The principle complements other concepts such as overload, specificity, and recovery.