The key principle in any aerobic or anaerobic exercise plan is called Progressive Resistance. Progressive Resistance means gradually and continuously increasing your total exercise workload. Your body has a great ability to adapt to its environment. Only by the adding of resistance can you grow and develop. As your body becomes accustomed to one level of exercise, the speed of progress reduces. In order to make steady gains your body must be physically stimulated. This can be done in several ways: 1) by adding resistance in mass (anaerobic exercise) or METs (aerobic exercise); 2) by doing the same volume of exercise in less time; 3) by including more exercises in your workout plan; 4) or by adding more exercise days to your schedule. How often and how much you increase the resistance by depends upon your age, available time, functional capacity, and ambition for success. The BioFitness Institute uses scientific formulas to automatically adjust your Progressive Resistance increases. The BioFitness Institute matches your ability with an appropriate projected rate of improvement. This combination of details and progress rate creates the ultimate in workout planning. You know what to do, how to do, when to do, and the results you can expect to achieve ahead of time.