There really is no one answer to that. I don't consider myself a runner at all. I'm definitely not built like a runner. The only reason I ever did run in my early life was because someone always said we had to, for conditioning be it for football, basketball or baseball. While others complained about it, I always secretly enjoyed it. I loved that burning feeling in my lungs when you're just about tapped out from doing sprints over and over and over again.
I think its when I went to Junior College to play baseball that I truly discovered running. I mean running on my own without anyone telling me I had to. I can still remember running from my dorm room to the Cochise College Rodeo grounds early in the morning. The sunrise, the smell of a fresh morning rainfall, and so on. It just became second nature to me. I loved it. Even if I was hung over from the night before, I would still make myself go out and run, because quite honestly nothing cures a hangover like a long hard run.
I continued my running ways even when I transferred to New Mexico State University to continue playing ball. I would run around the campus at night to clear my head a bunch. What I remember most about those night runs was passing the married with children housing and being able to smell whatever Mom or Dad were cooking up for dinner.
Towards the end of my college baseball eligibility I met this group guys who called themselves triathletes. This is really when I discovered endurance running. I thought I could run, but holy shit these dudes could run and run all friggin day.
Not to long after discovering Triathlons I moved to Washington DC, where I discovered bike racing. I kind of left my running to go at this new venture. I still ran but not like I was accustomed to. I did the bike racing thing for 4 or 5 years. I then met Erin, my wife and got married and not to long after we had 2 beautiful kids. All the sudden I wasn't riding or running much. I really didn't notice much but I slowly started putting on weight. Around 2008 I weighed close to 215lbs.
I think it was around 2009 that my wife decided to run the Marine Corps Marathon. She asked me to help her train and before I knew it I was going out running with her with both kids in the double jogger. It was tough at first, but slowly my muscle memory kicked in. As the Marine Corps Marathon came and went I continued running. It is now 2011 and I weigh 182 lbs and can run a 5k in 17 minutes.
I'm going to make 2011 my running year. I'm doing a 10 mile race, a half marathon and an off road half marathon all in the next two and a half months. Its going to be a BADASS year.