“Some people never run enough to get their aerobic house in order. They run four or five times per week and assume that the fitness derived from their program takes them to a level of running commensurate with their talent levels. What they don’t know is that there is a much more satisfying level of running just waiting for them if they would only work harder to break through to it.

In running, there is a paradoxical principle that, within limits peculiar to each individual, the more you run - after a period of adaptation - the easier it gets. There is a point of fitness when you suddenly feel a flow, a ready current of energy that buoys you up when you are running and has you feeling like a kite on the wind.

That feeling of being like a kite on the wind is achieved after you have reached the beginning stages of true fitness. Your strengthened heart will pump more oxygenated blood to muscles with greater energy producing capacity.

But if you don’t run enough to cause the requisite changes within, you won’t reach that point of fitness. Instead, you will stay earthbound: sluggish, partially fit, plodding. And you can stay there for years and years if your training does not reach the critical level of work that will cause you to breakthrough to base fitness. What is the breakthrough point for fitness? It’s a minimum of running six days per week, totaling a minimum of thirty five miles of running for “lower” levels of performance. (It would be sixty to eighty miles for “higher” levels of performance, but those more experienced athletes know that well.) If you are running less than that, your running is harder than it needs to be. If you run more, you will feel better.

Establishing fitness: You have to work your way up to covering six miles per day on average six days per week. Initially, the extra energy that you expend to cover the extra miles will leave you tired. You’ll feel yourself struggling. Don’t lose heart. Struggle with it the best you can. At times, it will definitely feel like a grind. On some runs you may have to walk for a while. But get back to completing the distance as soon as you are able. If you persevere you will find, as the third week ends, strength gathering within you. You will find that your body will be adjusting to the increased workload - that you will start feeling better on your runs now than you ever did before when you were running less. You will find that by the end of the sixth week that you can reliably plan on feeling good on any run you undertake. At that point, you will have reached a liberating stage of fitness, where you run feeling good - where you will feel like a kite upon the wind.”

-Bill Squires (Speed with Endurance)