The 50K is widely considered the gateway to ultrarunning. Here’s how it got started in the United States.
“If it doesn’t go very well, I’ll just go home.” That’s what Jen A. Miller told herself in 2016 when she was training for her first ultramarathon, the Labor Pain 12 Hour Endurance Trail Run. “To say, ‘I’m going to go to this 12-hour race and see if I can run a 50K,’ was actually not that scary,” she said. Labor Pain, set on a 5-mile, wooded loop outside of Philadelphia, is a community-oriented race and Miller, an award-winning freelance writer and author of Running: A Love Story, had a handful of marathons under her belt. Plus, the field was sprinkled with runners she’d gotten to know at local races. “It was like, ‘everyone is here to do their best today,’” she said. “That was really comforting.”
Miller’s story isn’t entirely unique. A record 61,000 runners registered for and ran a 50K in 2019, up from about 20,000 runners in 2009, according to UltraSignup; for many, the distance serves as a sort of “gateway drug” for ultrarunning. “It’s approachable for anybody who’s run a marathon,” said John (aka Tropical John or T.J.) Medinger, former publisher of UltraRunning magazine, who has completed 150 ultras. Whether you sign up on an impulse or train for months to compete, running 31 miles is a rite of passage in the trail community. Here’s everything you need to know about the history of the distance.
It’s almost impossible to pinpoint when someone ran the first 50K. North Americans, including Indigenous groups, have been running long distances for hundreds of years. Pedestrianism, or competitive race-walking, predated ultrarunning in the 1870s and 1880s. People now run ultras for spiritual and advocacy reasons. They also run for fun, or to see how fast and far they can go. In 1911, in one of the first organized races resembling a 50K, 14 runners took off from Bellingham, Washington, with a goal of summiting 10,781-foot Mount Baker and returning to town in 24 hours, according to Ultrarunning History. (Participants reached a trailhead by train or auto, then ran 28 or 32 miles, depending on the route.) The race involved crossing snow fields at night, when they were most stable, without the use of battery-powered flashlights and headlamps.
But the 31-mile event most trail runners know and love today dates back to the late 1970s, when ultrarunning was still in its infancy. The Bay Area Skyline 50K Endurance Run, held the first weekend each August, is one of the oldest U.S.-based 50Ks that’s still going strong. The original point-to-point course traced a ridgeline route through the East Bay Regional Park District. T.J. Medinger credits the initial 1982 event with jump-starting his ultrarunning career.
“It was my first trail ultra,” he said. Prior to the race, he’d run trails maybe a total of ten times. “After patchy ground fog at dawn, it turned into a really hot day. In the very early miles, we ran along a fenced meadow that contained a half-dozen horses that galloped with us,” he said. “It was just so very cool. I remember it clearly all these years later.”
From Skyline, Medinger, who now serves on the advisory council for Western States and founded the Quad Dipsea and Lake Sonoma 50, went on to run classic races like American River and, eventually, Western States. “By the mid-1980s I had completely converted to a trail runner and an ultrarunner. I never looked back,” he said.
Just shy of 300 runners participated in the inaugural Skyline, including Bob Cooper, who placed second overall, and Bjorg Austrheim-Smith, who placed first among women. Today, attendance is similar with about 200 runners having competed in 2021, despite many more events vying for their attention. In a 2017 ode to the race for Trail Runner, Sarah Lavender Smith wrote, “It’s for first-timers and old-timers more than sponsored ‘elites.’ Like a favorite old shoe, it feels good and doesn’t wear out. Always friendly, never flashy.”
“Skyline is a lesson in what makes ultrarunning special,” said current race director Adam Ray who has also run many ultras. “It’s one event where you can be sure that you’re going to see people who have run at all parts of the pack at different phases of their career, who are open with their hearts and their stories.”
In this way, the story of the 50K mirrors the history of ultrarunning. Chris Ripley, who has also run 150 ultras and founded Washington state’s first 31-mile trail race, the Ron Herzog 50K (formerly the Granite Falls 50K), said trail running’s community spirit drew her in and kept her going. “At the end of my first 50-miler, Jed Smith, the guy who won the 100-miler came over to me and said ‘Congratulations,’” she remembered. “What I found in ultrarunning more than in marathons is that people are so friendly.”
There are a dizzying array of ultra distances. The 100K is popular all over the world, whereas 50- and 100-mile races are more common in the United States, where imperial measurement prevails. Runners from across the globe participate in 50K events, including world record competitions. Desiree Linden currently holds the 50K world record for women, while Stephen Mokoka holds the record for men.
The number of North American 50K races has grown steadily over the last 20 years, according to UltraRunning magazine. In general, more people are running ultras than ever before, per a 2020 study by Run Repeat and the International Ultrarunning Association, which found that participation increased by 1,676% since 1996. “When I was the publisher of UltraRunning magazine, we’d get calls from the press when something would happen,” Medinger said. “People wanted to know, ‘What’s an ultramarathon?’ Now it’s common usage,” he said.
When Medinger and Ripley were getting their start, they began running marathons on roads and shifted to ultras on trails. Today, longtime runners say they’re seeing runners enter the ultra community without a road-running background, though there isn’t formal research to back this up.
Experienced ultrarunners are quick with their words of encouragement. “If you can run a marathon, you can run a 50K,” they like to say. But those 4.8 extra miles demand a leveling up. “Even though it’s just five more miles, running 50K on a trail takes much longer,” Medinger said. “A three-hour marathoner might take five hours to run a trail 50K.”
Still, “I think anybody can do one,” Medinger said. “One of the great things about ultras in general is just how encouraging everyone is.”
There are free online resources for preparing for a 50K, including guides from Vert.run, Outside magazine, and REI. Your running community—whether online or in person—is another place to look for advice and encouragement.
“Take advantage of all of the comfort that trail running offers, in terms of camaraderie and advice,” said Ray. Find a trail-running group and share your goal with your running buddies. “You’ll get more advice than you’ll probably ever need. Trail-running is a grassroots pursuit, and there are a lot of people to share it with.”
With that in mind, we asked the pros for their advice on preparing to run 31 miles—whether it’s your first or fiftieth 50K.
“Choose an established trail race and make sure it’s mountainous,” said David Horton, who has run more than 160 ultras and directed dozens of races including serving as current race director for Virginia’s Promise Land 50K. If it’s a road race, he said, you may run too hard and fast.
“Don’t try to translate your marathon time to what your 50K time will be—especially if you’re going from roads to trails,” Miller, the Running A Love Story author, said. “You could run the same race on the course with different weather conditions and it’s a totally different game.”
And, “always take what the course gives you,” Ray said. “The biggest mistake people make early on in trail running is running when they should be walking and walking when they should be running.”
Tia Bodington, race director for the Miwok 100K, was surprised by how relaxed she felt during her first ultra, “I had thought I would spend the race pondering my job, my kids, my life,” she said. “But instead my brain let go of the past and the future and I found myself in the present moment … Time didn’t stand still, but I could no longer feel it ticking.”
Ultimately, Medinger advised, “Just go run. Run really easy for the first twenty miles—cruise along and enjoy the scenery and conversations with people around you. If you’re still feeling good at 20 miles, then put the hammer down.”
After eight laps around a wooded track on what turned out to be a beautiful day, Miller hit her goal of running 50K in the Labor Pain 12 Hour race. She said she felt buoyed, in part, by the event’s laid-back vibe. “Between every lap, I’d go over to my beach chair, drink some water, Gatorade, have some cookies my mom made for me … and then I was like, ‘OK! You gotta keep going.’”
Since then, Miller has run a handful of ultras, including the Blues Cruise 50K in Reading, Pennsylvania. She likes the loop format. “People think they’ll get bored with a loop race. I could see that, but I like it,” she said. “There’s something to knowing that I’m going to see all the same people again and again. They’re going to be able to tell me if I’m looking really bad.”