While there are some exceptions to this rule, it is important to try to progress on a very regular basis, by reforming repetitions, resistances, or routines. This won’t necessarily occur during each workout, but overall progression will probably continue to improve each week, at least until you are at a level of fitness which you’d like to maintain. Progression doesn't always need to coincide with an improved physique or performance. Larger and stronger muscles show definite progress, but so does any systematic modification to any aspect of your program − reps, sets, exercises, or resistances. Big or small, one step at a time is still progress.
Keep in mind that, with progression, there is also a law of diminishing returns. The most dramatic results of any program always develop from the least amount of exercise. The difference between doing absolutely nothing and next to nothing is tremendous. One minute of properly performed exercise for each muscle group, even if only performed once a week, can elicit phenomenal adaptations. As you progressively increase your numbers for exercises, sets, reps, or resistance, more always means less. A little more may be beneficial; however, past a certain point, progression increases time investment and probability of injury.
Also, as the intensity of your workout increases, training duration should actually decrease. Your body only has a limited quantity of energy that can be used either for hard work or for long work − but not for both. As you become more conditioned, your workouts can be designed to be progressively harder, yet also progressively briefer.
An intense resistance training routine is almost impossible to sustain for over an hour; in fact, more often, shorter is better. Some of your most productive workouts will actually be performed in 15 minutes or less. Longer workouts almost always reflect a lower-than-optimal training intensity. Finish fast to finish strong!!!
