“You will never know your limitations until you FIND them.” That is what I love about running, specifically ultras, you are constantly pushing the limits of your own perceived endurance. Overcoming the fear of failure and the fear of inability is what it’s all about. The more you push, the more the limits expand.
As a runner, I have come to believe that limits are set ONLY in our minds. This means that WE are the only ones that decide how much our bodies can take. Training is only part of it- of course, it can change how MUCH we rely on the second part- Attitude is the most important part. How bad you want it. How hard you are willing to push it. How important it is to finish.