Final answer:
The 'I' in the FITT principle stands for Intensity, which is a measure of how hard someone works during their exercise routine.
Step-by-step explanation:
The FITT principle is a widely recognized framework used in exercise physiology and physical fitness to guide the development of effective workout programs. Each letter in FITT represents a key component of a well-rounded exercise routine. In this context, "I" stands for Intensity, referring to the level of difficulty or exertion during physical activity.
Intensity in exercise is a measure of how hard the body is working. It can be manipulated by adjusting factors such as resistance, speed, duration, or the amount of weight lifted. The appropriate intensity varies based on individual fitness goals, fitness level, and the type of exercise being performed.
For cardiovascular exercise, intensity might be measured by heart rate, while for strength training, it could be the amount of weight lifted. The FITT principle helps individuals tailor their exercise programs to achieve specific fitness objectives by providing a structured approach to manipulating Frequency, Intensity, Time, and Type of exercise.