Pain and suffering

Pain: An unpleasant sensation occurring in varying degrees of severity as a consequence of injury, disease, or emotional disorder. Suffering or distress. When people talk about the pain of a hard race are they referring to screaming lungs, burning muscles, the urge to upchuck after, or some sort of injury-like pain like one experiences with shoulder injury problems? It is this last that I generally associate with the word pain but the former which I associate with hard swims. Am I just not swimming hard enough? To what extent is suffering and distress intrinsic to effective training? In my running days long slow distance was enjoyable while sprints and intervals and shorter distance races seemed to be largely an exercise in tolerance for suffering and physical distress. It seems like swimming is kind of the same. As I try to concentrate more on speed and shorter distances I am starting to wonder occassionally about why I want to subject myself to so much suffering. ;) I sometimes wonder if on top of technique the people who started swimming early in life have also developed a greater tolerance for suffering? Or perhaps this is an attraction of swimming, the idea that you can improve by improving your technique instead of improving your ability to tolerate suffering? I don't know, these are just some of the thoughts that drift through one's mind as one drives home after a workout in which one finds oneself draped over a lane line gasping for breath and suppressing the urge to puke...