The longest distance I have ever run was 10k last March 2011, and at some point there, I did find myself wondering why I had to stick it out when my thighs were screaming "Stop! I hurt already!". At that time, I wanted to run that distance for the sense of accomplishment I could derive in knowing that I was no longer limited to the usual 5k. Almost a year later, I'm eager to start training again, but this time, my purpose has progressed from simply pride and honor to love and faith.
When Michael decided to get back into running, he specifically wanted to do so in memory of Brooke, our darling daughter. Not only that, but he had in mind to use running as a medium for spreading the message of perseverance that Brooke taught him and also to make a difference, no matter how small, by joining races with a specific cause. When he's short of breath and tempted to give up during training, it's the thought of Brooke that fuels him to keep going. I'm sure it's the bigger purpose that Brooke gave him that will push him forward when he's struggling to complete his goal of finishing a 21k race before the year ends.
When I start running again, I know it won't be easy. Despite being physically fit for most of my life, by the time I recover from my CS operation, it will be like starting from zero. I will have to build up my endurance and strengthen my leg and core muscles like a total newbie. It will most definitely take some time before I can run a 10k, let alone a 5k, race again. But I know that I need only to remember my daughter's beautiful face to keep me running not only until I regain my strength, but until my legs can no longer move. Yes, I plan to keep running my whole life.
Some runners I've spoken with say they run specifically to look good and maintain good health. One runner says he doesn't like running at all, but does it (and even excels at it!) because he's a triathlete and running is part of it. Another ultramarathon runner is driven by the thought of his son and daughter. Whatever your purpose, it's worth a minute to go back to your reasons from time to time. Running isn't all about the physical capacity of a person after all. It involves a runner's heart, mind, and spirit, and how willing he is to give it his all for the purpose he set out for to begin with.