VAIL, Colorado - At more than 8,000 feet, a tiny hill on what appears to be a totally flat race course feels like a mountain.Athletes tested their endurance on the 10K Nordic freestyle ski race Friday morning at the Vail Nordic Center - and even these insanely fit athletes crossed the finish line huffing and puffing.Some fell to their knees and some on their backs after the finish - it had been more than 20 minutes of an all-out sprint - skate skiing across a deceivingly flat course that presented some twists and turns with its deceivingly small hills.Husband and wife team Brian and Caitlin Gregg won the men's and women's race, respectively. The couple traveled to Vail from Minneapolis, Minn., about two weeks ago to get acclimated before Friday's event.Back in the Midwest, Nordic ski races are commonplace and there could be 500 competitors on any given weekend, Brian Gregg said. While the start list Friday was a fraction of that, the couple was impressed with the Nordic community they found in Vail - especially the hospitality here."The Ski & Snowboard Club Vail group - they've been helping us out all week here with wax, etc.," Brian Gregg said. "They're a very classy group to allow their competitors to use their resources - just a super, super classy group."Coming from 800 or so feet above sea level to more than 8,000 is tough work just for the average person, never mind an athlete sprinting on Nordic skis for 10 kilometers. Caitlin Gregg said the course was surprisingly hard."You're always working. You don't get a lot of rest out there," she said. "Any little downhill, I thought, 'Oh, thank goodness.'"Dan Weiland, Ski & Snowboard Club Vail's Nordic program director and the chief of course for Friday's race, loves seeing elite Nordic racers in his backyard. He grew up skiing in Vail and said it's slowly getting on the map when it comes to Nordic skiing. An event like the Winter Mountain Games certainly helps give the sport more exposure, he said. Some of the athletes took the time to cool down with the young Ski Club athletes after Friday's race, too, which Weiland said means a lot to young racers who look up to these athletes. Sylvan Ellefson, 26, of Vail, was once one of those athletes. He was born and raised in Vail and went to the Vail Mountain School. "This is actually the biggest - in terms of size and prize money - race I've ever done at Vail," Ellefson said. "It's nice being able to come out in front of the home crowd and try to show off."Ultimate Mountain ChallengeFriday's Nordic 10K was the first of three events in the Ultimate Mountain Challenge - Saturday's Ski Mountaineering race and Sunday's Vail Uphill are the remaining two. Reigning Ultimate Mountain Challenge men's champion Brian Smith, of Gunnison, hadn't raced anything short like a 10K in a long time until Friday. He said the race was intense. "I tried to stay with the front guys and it kind of blew me up after the first 5-10 minutes," Smith said. "I had to settle and get my own pace. I was definitely struggling a little bit out there.Smith came in about half-a-minute behind Stephen White, of Eagle-Vail - plenty close to keep his confidence going into the rest of the weekend. White wants a little redemption from last year, though, after barely cracking the top 10 in the Winter Mountain Games inaugural event. Coming out of the Nordic race in the lead for the Ultimate Mountain Challenge, White is now focused on a podium finish on Sunday. He hopes being the hometown guy gives him an edge in Saturday's ski mountaineering race.On the ladies' side, Inge Perkins heads into ski mountaineering with the Ultimate Mountain Challenge lead. Perkins, who is from Bozeman, Mont., but lives in Durango, wants to get ski mountaineering out of the way before she gains too much confidence. She said the Nordic event was definitely a strong event for her, even though there were challenges on the course. "It was really fun. It's just so pretty here," Perkins said. "I just look up at the mountains and enjoy myself."