June 6, 2012 marked the fourth annual National Running Day. The event was created to provide a day where runners across America could take to the streets and celebrate one of the only sports which welcomes participants from all walks of life, all ages and all levels of athleticism. It was a day to celebrate not only running but also the people who do it. The motto of the day celebrated all of the reasons why people run: "I Run...(fill in the blank with your own reason)"

MarathonGuide.com had the special treat of celebrating the day in New York City's Central Park with a morning run with soon-to-be 2012 Olympic Marathoner Desiree Davila, ultramarathoner Scott Jurek and President and CEO of the New York Road Runners Mary Wittenberg - all icons of the sport.

Because the day was a celebration of running and a hope that more will start to run; we asked Desiree Davila and Scott Jurek their thoughts on what challenged them when they began and what challenges them now as professional athletes in the sport.

Davila had early roots in soccer before transitioning to running: "In soccer, running is the punishment. You'd go run a lap and it just happened that I was good at it; but it's not something you did every day and transitioning from 'this is no longer the punishment, this is the reward' and going on to be excited about running...was the difficult part - mentally. But once you get out the door and get going you feel good and then you think this is exciting."

Even after reaching the peak of the sport and earning a spot on the Olympic Team, Davila still finds similar challenges as a professional athlete as she did when starting out. "Sometimes, it's still just getting out the door. In the winter on the nasty days, it's tough to make yourself motivated to go out and run when you just don't feel like it...Running year after year, it's the same thing. You have to get out and get the first mile in and all of a sudden you feel a lot better. So that really hasn't changed, but it's gotten a lot easier."

Davila was in New York to participate in the NYRR Women's Mini 10K, the 40th anniversary of the all-female event that was a precursor for women to officially participate in long distance running events. She will follow that with the 2012 London Olympics and then focus on her wedding preparations for August 2013.

Scott Jurek has logged more miles than most people would think is humanly possible; but everyone starts somewhere - "I think I had problems just like everyone else - side aches and runners trots and things like that. I think growing up in rural Minnesota there were just not a lot of runners on the road when I started 20 years ago..."

Jurek advised, "I think the biggest thing too is staying motivated to get out - having a goal and a purpose to get you out in the morning, afternoon or evening and having other people to get you out is helpful. Join groups and have a running buddy, because sometimes it's great to run by yourself but it's nice to have that motivation - a reason to get out there."

Jurek best known for victories in ultramarathons including the 153-mile Spartathlon, the Hardrock 100, the Badwater 135-mile, the Miwok 100K, and seven consecutive victories of the Western States 100 Mile Endurance Run still faces challenges as a competitive runner: "I think mentally having competed for so long it's hard now. I was so motivated in the early and middle stages of my career. I've done all these things, so it's like what's next? And finding things and challenges that motivate me to train as hard as I can is key. I think having a really good attitude towards running is important, because so many top athletes tend to just stop running or they just kind of drop off. For me, I want to have this attitude: get back to the sport, stay involved in the sport, volunteer...and still run races...and maybe run races for fun."

Jurek's new book "Eat and Run" launched in New York the day before National Running Day. His book tour takes him first to Boston before passing through many major cities in the USA - look for him at a stop near you.... Next on Jurek's race calendar will be the 24 - Hour Run World Championships in Katowiche, Poland in early September.