The Overload Principle can be achieved through changes in Frequency, Intensity and Time. What is all that, you ask? To start off, frequency, as you may suspect, is how often you exercise. How often is enough is the question. Well, most people say anywhere from 3 to 6 days a week, depending upon experience and goals. Training the full 7 days most of the time isn't the answer to improving your body's performance and health. Intensity is how hard you push, what level of effort your body performs. Depending upon whether you're looking to stretch a workout over a long period of time and work at a slower pace than normally, or race 100 meters at 100% decides how hard you will train. You can work at full throttle for 5 minutes or ease it up for 15, and still get the same benefits. That leads to the third principle of time. For how long do you wish to train? That is a question only you can answer. When you're working your way up from 5 minutes to 10, then the next couple of weeks up to 30, you're doing something. Time plays a very important role in the three principles of fitness, but like a three-legged stool, if one is missing, everything will fall apart.