Rachel Toor, author of Personal Record: A Love Affair with Running (2008), didn’t start out as a runner. In fact, she considered herself a bookish egghead who ran only to catch a bus. But since she ran her first race more than 20 years ago, she's finished dozens of marathons, qualified numerous times for Boston, and run many ultra-marathons and other endurance races, too.

Toor is now sponsored by Athleta. For the next year, she'll blog for the clothing company about running, 2012 resolutions and above all, enjoying the ups and downs of life.

Read her first blog post here titled "Imposter Syndrome."