It's the weekend of the Superior 100-Mile race on Minnesota's North Shore, but ultra-distance runner Austin Nastrom can relax. He just managed the equivalent of three, covering the 310-plus miles of the Superior Hiking Trail and putting his name among record-holders who've covered the entirety of the path the fastest.

Nastrom, 24, of La Crosse, Wis. (and formerly of Blaine), put down the "fastest known time," aka FKT, a bit after 2 p.m. Sept. 3 when he reached the southern terminus of the trail at the Minnesota-Wisconsin border near Jay Cooke State Park in Carlton, Minn. Nastrom left the trail's northern point on the Canadian border early Aug. 28. He hiked and ran the trail in six days, eight hours and 37 minutes. His is the new record for an FKT with support, eclipsing Cameron Schaefer of Mound, who set the supported mark July 10. FKTs are broken into three types (supported, unsupported and self-supported), and attempts have ramped up on the North Shore so far this year.

Nastrom sent his tracking data to FastestKnownTime.com, the keeper of the records from around the world. The website posted Nastrom's mark Wednesday.

Nastrom was paced the final miles by Ajay Pickett of Woodbury (shown above right with Nastrom on Sept. 3). Pickett holds the FKT on the Superior trail unsupported, during which he carried his own supplies over seven days, 20 hours and 56 minutes last September. Jeremy Platson set the self-supported mark in eight days, two hours and 35 minutes in fall 2016, leaving supplies for himself in advance along the route.

In a nod to the camaraderie of ultrarunning and hiking, Pickett and Nastrom connected months before Nastrom's attempt to share notes.

Pickett said meeting up with Nastrom is indicative of the wider FKT community.

"(It's) very supportive of other attempts even though it's very competitive. Helping others push the boundaries even if that means they break your record is a very fun part of it," he wrote in an email to the Star Tribune.

Nastrom, business manager at a coaching business called Trail Transformation, is a veteran of the gnarly ups and downs of the Superior Hiking Trail. And that knowledge, coupled with his challenging ultra runs in Colorado at the Leadville 100 (miler) in 2017 and Ouray 100 last July, gave an FKT attempt over 300 miles added resonance, he said. It didn't seem "impossible."

Pickett agreed with the thought. "I think FKTs have become the ultimate accomplishment for both runners and backpackers. It's the natural evolution to 'What's next?' For runners, once they accomplish a 100-mile or 200-mile race, FKTs seem to be the next logical step."

Nastrom's next steps were calculated: when to attempt it (late summer) and how (north to south). He said there are more access points in the southern half of the trail – opportunities to connect with his support crew more often – and better cellphone reception. He said his parents, Brian and Melinda, girlfriend Megan Molling, and Rachel Turi, dietitian and business colleague, were huge support. His brother Blake, a student at Minnesota-Duluth, also rallied around his final push.

For all the preparation, Nastrom said the path revealed its rugged might in new ways during the FKT. "I definitely underestimated the trail," added Nastrom, who knocked off nearly 120 miles in his first two days. Then, he cut back his daily mileage -- the pounding was unsustainable. Managing his distances -- and an increasingly sore and swollen ankle -- he left about 20 miles for his final day.

"I wouldn't say (the reduced mileage) got easier," said Nastrom, "but I got accustomed to it."

Superior trail races director John Storkamp of Rocksteady Running hailed the achievements of Nastrom, Pickett, Platson, and others, and anticipated more FKT attempts Up North.

"Tackling an FKT on the Superior Hiking Trail is no joke, so just getting to the 'start line' of your attempt can be a feat," he said. "I think some of those daydreams took a while to become plans and then ultimately attempts. I think more are coming."