He had to stop a 100-mile run in the Mark Twain National Forest. Disappointed, DeKeyser ran and finished another 100-mile ultramarathon three weeks later.
He once conquered 100 miles in 23 hours and 43 minutes.
"It gives you a lot of time to reflect on things," DeKeyser said. "You hit these incredible highs and then you hit these incredible lows. And it's all in the span of an hour."
DeKeyser is a member of Peoria's tight-knit trail running community. Trail runners shun the road in favor of more natural paths. Instead of pavement, they seek sometimes-frozen, rugged terrain. They run through forests and up hills, with rocks, roots and pits.
"I just became addicted to it. It's so much more peaceful," DeKeyser said. "You're with trees and wildlife rather than cars."
There are a series of spring trail running events in the region, including the Cactus Classic Trail Race on March 9 at Sand Ridge State Forest near Manito. Runners have three distances to choose from: 10 kilometers, a half-marathon or a full marathon.
Because of the terrain, falling is common, said Elmwood's Colleen Karn, who suffered a wipeout in February during her second-ever trail running race.
"I heard you're not a real trail runner until you've fallen," she said.
Karn started running two-and-a-half years ago but took to the trails just last spring.
"I've always kind of loved playing in the woods," she said. "It's a lot tougher to run a trail because it's uneven. The hills are really steep don't ever expect to run a trail run at the same pace you run on the road."
The trail running community.
On the trail, the camaraderie is evident. People stay in packs, warning one another of dips, twists and low-hanging branches. Runners sometimes bury beers to share during the late stages of ultramarathons, which are any races longer than the traditional marathon of 26.2 miles.
Trail running came to Peoria in 2007. Race directors decided it was time to add trail running to the roster of events already in the area, said Peoria's Steve Shostrom. He was inducted into the Greater Peoria Sports Hall of Fame, he co-founded the Illinois Valley Striders running club and he helped establish trail running in the city.
"I think (the Central Illinois Trail Running Alliance) has developed races that appeal to people starting out on the trails. At the same time, their trail races really appeal to runners that need more than your every weekend charity 5K," Shostrom said.
While 90-120 runners participated in early trail events, nearly 300 people currently run the bigger races, said Chris Dierker, who has organized races and volunteered for the organization. In 2012, about 1, 200 people participated in CITRA races.
"It's more of a community feel at those (trail) races (than at road races). It feels more like family," said Dierker, who lives in Peoria.
Trails also offer scenery runners are unlikely to find on a sidewalk or street.
"The freedom of running trails through the woods, creek crossing and hills (is exhilarating)," Dierker said. "It's just a real diverse challenge to running."
Dierker has finished 50-mile races and is looking to do so again.
"You run your longest distance ever and then you start wondering, 'OK, how much farther could I go?'" he said.
Those lengthy distances keep some trail runners going. Pekin's Eric Skocaj runs 50-milers three or four times per year. He said 10 miles turned into 50 and then more.
"You're bound to hit a point where you're just mentally beat up and I like getting to that point and trying to push through it," Skocaj said.
The 27-year-old and his father, Richard Skocaj, organize the Potawatomi Trail Runs at McNaughton Park in Pekin. Taking place April 5-7, the event offers four distances: 150, 100, 50 or 30 miles.
Making a connection.
Runners can also find unique trail runs in east-central Illinois. On April 6, Dean Hixson will host the inaugural Allerton Trails Half Marathon and 10K.
Hixson moved to Monticello seven years ago, and gravitated to Allerton Park. However, a broken bridge separated two sets of trails. With the Sangamon River racing through, runners and hikers couldn't cross over.
When the south entrance bridge reopened last fall, Hixson started thinking. He wanted to take friends on a run celebrating the connection of the trails. But he eventually charted a half marathon course and realized he could create a race and donate the funds to the Make-A-Wish Foundation. More than 300 runners are currently signed up. These trails are mostly flat.
"There is obviously something primal about getting out there on your own in the woods with wildlife," Hixson said about his time spent at Allerton.
Running fosters appreciation for the outdoors. so I have the capacity to run further and see more trails," he added. "It can be such a beautiful experience."