To a long-distance trail runner like Matt Hart, the Teton Range was a wide-open canvas for setting a speed record on a challenging mountain route.

Last month, armed with maps and an eager group of friends, the 33-year-old ultra-endurance athlete took his skills to the trails of Grand Teton National Park to carve out a stunning speed record on a Teton loop that would take most hikers two days to complete.

Hart’s 33.7-mile route circumnavigated the high peaks of the range, gained more than 8,000 vertical feet and took him a cool six hours, 29 minutes to complete July 29.

“I thought it would be cool to set up the route and see what people can do,” Hart said. “It’s pretty easy with all the awesome trails in the Tetons to figure out a logical loop.”

Hart’s day in the mountains, (hardly long compared with most days in the Tetons) started at 6:53 a.m. at the junction of the Cascade Canyon trail and the Valley trail at the northwest end of Jenny Lake.

He then ran a counter-clockwise loop up Cascade Canyon, over Hurricane Pass and down into Alaska Basin. Heading south, Hart passed over Static Peak Divide before descending Death Canyon.

He finished his run by heading north on the Valley trail past Taggart and Bradley lakes to the junction where he left. It was 1:21 p.m.

“There’s other ways I could have started the loop, but I wanted to soak in some cold water when I was done,” Hart said.

“That’s why I did the String Lake start,” he said.

Hart and three running friends had scouted the route the previous day, taking photographs and testing a new water filter. It took the group 9 hours and 27 minutes, but Hart was so enthused by the route’s scenery and challenge that he returned to establish his mark the next day.

“The races are fun, but for me it’s all about the training and pushing my limits,” Hart said. “On the speed attempt, I fell into snow up to my waist at one point.”

Despite his early start, Hart didn’t have any wildlife encounters on his speed attempt, though he saw a bear with his three partners a day earlier. He carried only his own water bottles and didn’t stop to filter any water.

One obstacle during his descent into Death Canyon was avoiding hikers he encountered on the trail.

“For the most part, they were pretty great,” said Hart, who tried to announced his presence as early as possible. “They usually stepped to the side if they were hiking. If they didn’t hear me, I’d run off the side of the trail.”

A native of Portsmouth, N.H., Hart worked for Microsoft Corp. in Seattle until 2005, when he quit his job to pursue racing full time.

A member of the Montrail National Ultrarunning Team, Hart also competes in adventure races. In September, he finished second in the Grand Teton 100-mile race, where he began a relationship with organizers and coaches Jay Batchen and Lisa Smith Batchen.

This spring, after encountering the couple at the Bighorn Trail Run in Sheridan, Hart agreed to work with the pair as a coach for their ultra-running camps. He relocated to Driggs, Idaho, earlier this summer.

“You can always refine your technique and get faster and faster,” said Hart, describing his interest in ultra-running. “The feeling I get after doing a regular training run or finishing a race is not a feeling you can really duplicate anywhere else.”

After consulting with Jay Batchen and poring over maps, Hart came up with the Cascade to Death canyon loop. Hart wanted to attempt the run July 4 but was thwarted by snow.

“I ended up going up Table Mountain with friends towards the end of July, and when I scouted the snow levels, it looked doable,” Hart said. “It’s about a 50-k, and I’ve raced that distance a lot.”

Though informal speed records for ascents of the Grand Teton and Grand Traverse have circulated for years in climbing circles, Hart’s publicly announced speed record may be the first of its type in a community where athletes regularly keep accomplishments private.

According to Hart, Salt Lake City ultrarunner Jared Campbell has already made two bids to beat Hart’s mark, but both were unsuccessful.

He knows a group of elite ultrarunners based in Oregon also has the route in its sights, but he’s also hoping some of the valley’s top ultrarunners will take a crack at the route.

“If someone breaks it, I’ll try to come back and go a little harder,” Hart said. “I’d do the runs anyway, it just adds another interesting twist to it.”