Haruki Murakami said this quote
“ Of course it was painful, and there were times when, emotionally, I just wanted to chuck it all. But pain seems to be a precondition for this kind of sport. If pain weren't involved, who in the world would ever go to the trouble of taking part in sports like the triathlon or the marathon, which demand such an investment of time and energy? It's precisely because of the pain, precisely because we want to overcome that pain, that we can get the feeling, through this process, of really being alive--or at least a partial sense of it. Your quality of experience is based not on standards such as time or ranking, but on finally awakening to an awareness of the fluidity within action itself. ”