Covered in dirt and sweating from head to toe, Ben Stern smiles and takes a long swig of water to hydrate his depleted body as the Northern California sun intensifies on the open fields around him.

This is a familiar scene for the 24-year-old ultrarunner, who works five days a week at Little River Farm, an organic salad farm where he does “a little bit of everything” from digging up soil to planting, harvesting, washing, packing and delivering greens to local vendors.

“It’s some hard manual labor but I just really enjoy being active,” says Stern, who began working full-time at the farm last October. “And I’m outside almost 100 percent of the time, which is hard to beat.”

On Saturday, the Arcata resident will try hard to beat some of the best trail runners in the country when he lines up for the fifth ultra-distance race of his young post-collegiate career at the Tamalpa Headlands 50K, an annual Bay Area event, which this year doubles as the U.S. 50K Trail Championship. The race boasts a loaded field, including reigning U.S. mountain running champion Patrick Smyth of the Nike Trail Elite team, a 2:15 road marathoner who broke the course record earlier this year at the Way Too Cool 50K, Colorado’s Andy Wacker, runner-up to Smyth at the U.S. mountain running championships, two-time U.S. trail runner of the year Mario Mendoza, two-time national trail running champion David Roche, and a whole host of other off-road all-stars.

“When I signed up for the race I didn’t realize it was the national championships,” admits Stern, who will wear bib #9 on Saturday. “I just saw that it was local—the Bay Area is local for us up here—but now that I’ve seen how packed the field is, I’m not letting myself think that I’m not at their level. I would love to get a podium finish at this one and I’m not letting myself think that I can’t. If it’s a good day, it’ll be a good day, but if it’s not and I crash and bonk, I’ll at least know I tried.”

The unsponsored Stern made his ultrarunning debut last December at the Arcata to Willow Creek 40-Mile, an unsanctioned, underground event that has had at least one finisher every year since its inception in 1973. Stern broke the finish line tape made of toilet-paper in 4:46:12, an average pace of 7:09 per mile on the point-to-point road course along Highway 299 that traverses two mountain passes and features 6,000 feet of elevation gain. He defeated the race’s only other finisher, a woman in her 60s, by several hours.

In March, Stern lined up for his first official ultra race, the Gorge 100K in Oregon, where he ran with the leaders for the first two thirds of the race and ultimately finished third in 9:59:51. A little over a month later, he won the Miwok 100K in the Marin Headlands, clocking 8:50:45 to win by nearly 8 minutes. In late July, he won the Siskiyou Outback Trail Run, breaking Ryan Ghelfi’s 50-mile course record, clocking in at 6:30:17—30 minutes ahead of runner-up Hal Koerner, who was making his return to competitive ultrarunning after overcoming a long injury spell.

“I love the adventure aspect of ultra racing,” says Stern. “You get to run tons of miles of new trail and see places you haven’t seen. And I love to compete. That wasn’t the first inspiration for me to start running longer, but now that I am competitive and doing well, it’s the primary motivation. I want to win more races but really I just love running in new areas.”

Stern, who graduated from Humboldt State University in 2014 with a degree in environmental resources engineering, is no stranger to competition. As a junior in 2012, he clocked a 31:38 10K for the Lumberjacks at the NCAA Division II Cross Country Championships. On the track, he ran a personal best of 15:04 for 5,000 meters.

Now, training mostly solo on the hilly trails around Arcata, Stern takes a refreshingly simple approach to preparing for longer off-road races. He laces up his trainers six days a week, typically logging 60-70 minutes in the mornings before heading into work at the farm and another five hours—usually a 3-hour run on Saturday and a 2-hour run on Sunday when he’s in a peak training phase—on the weekends.

“The double long runs let me see things no one else in the area has seen,” Stern says. “It would take most people 9 hours to hike what I just ran in the morning. Not as many people are getting as far out in the forest as I am and that’s what inspires me to keep going.”

Stern does not post his training online, nor does he keep a blog. Unlike most competitive ultrarunners, the self-coached Stern shuns the use of a GPS watch for a basic chronograph so he can better listen to his body, allowing him to push hard if he’s feeling good and back off when his body tells him it needs a break. Most weeks, he runs a shorter, faster fartlek session on Tuesday and longer, more sustained intervals on Thursday or Friday. All of it is effort-based, with no pressure to hit a prescribed pace or specific splits.

“I’ve tossed away mileage, but I do track my time,” Stern explains. “I get too into numbers if I have the access to them. I had a GPS watch and I would look at it too much and it would frustrate me if I wasn’t running as fast as I felt like I would, so I just had to toss it away.”

On Saturday morning, Stern will try to cash in on the fruits of his labor when he lines up for his first post-collegiate national championship. The familiar scenario of working hard in the sun for a few hours—and the opportunity to kick up dirt against top-level competition on a challenging course that features 7,300 feet of elevation change—puts a smile on his face.

“I’m really excited for this one,” says Stern, who grew up in nearby Petaluma. “I’ve never been a speed guy but 31 miles is not that short. I’m attracted to hills and I feel I can be more competitive the hillier the course.”