I never would have believed it. In the past 7 months I have completed: -4 sprint triathlons and -5 half marathons including 3 half marathons in the past 6 weeks. For anyone who doesn't believe, you can! You just need to believe in yourself!
Yesterday, I ran 4.5 miles in less than 55 minutes. For the last quarter mile, with every step I was think "Now this is the furthest I've ever run. Now this is the furthest I ever run". Considering when I started training for my first 5K in late May/early June I could barely run a quarter mile, I was very amazed.