Writing and Running: A Comparison

I receive the "Runner's Quote of the Day" from the Runner's World website in my inbox every morning.  I got this one a few days ago, and immediately thought of it in the context of our final papers:

"Like writing, running is so much about mind over matter. There are times when you have to override the discomfort and keep pushing.  That capacity to endure and then prevail is just amazing."

Much like running, writing demands endurance.  But, the difference is between physical endurance and mental endurance.  Furthermore, writing endurance also demands that you have the ability to stop eventually.  To get up and walk away from your work, take a break, and come back later. 

That's the stage I am in write now with my final essay.  I have it completed (9 pages with works cited)...but I have LOTS of editing to do.  I find myself getting frustrated because it's really hard to keep looking at the same pages over and over again, and I feel like my brain just gets so full of the information.  Yet, I know that with my mental endurance, much like the physical endurance of running, this paper will eventually be finished and I will be proud of my work.