"I used to work so hard that I would often vomit after working out. This was whether I was at Jackson State or with the Bears. People would ask me why I could work like that even after I was a starter in the NFL, an All-Pro. I always had a difficult time workout out with other people who didn't share that belief. And I always thought, 'That's just the way you do it.' You work as hard as you can for as along as you can and the small gains you make will eventually pay off."
From "Never Die Easy" by Walter Payton with Don Yaeger