“Everyone knows what it is to start a piece of work, either intellectual or muscular, feeling stale… And everybody knows what it is to “warm up” to his job. The process of warming up gets particularly striking in the phenomenon known as “second wind.” On usual occasions we make a practice of stopping an occupation as soon as we meet the first effective layer (so to call it) of fatigue. We have then walked, played, or worked “enough,” so we desist. That amount of fatigue is an efficacious obstruction on this side of which our usual life is cast. But if an unusual necessity forces us to press onward a surprising thing occurs. The fatigue gets worse up to a certain critical point, when gradually or suddenly it passes away, and we are fresher than before. We have evidently tapped a level of new energy, masked until then by the fatigue-obstacle usually obeyed… In exceptional cases we may find, beyond the very extremity of fatigue-distress, amounts of ease and power that we never dreamed ourselves to own — sources of strength habitually not taxed at all, because habitually we never push through the obstruction, never pass those early critical points. ”
