Recovering from a life-threatening brain tumor. Moving on after a violent attack. Losing more than 100 pounds and finally feeling healthy.

These are the reasons three Denver-area people run, and now one of them could be on the December cover of Runner’s World magazine. Jill Howard of Highlands Ranch, Amanda Osberg of Littleton and Bard Parnell of Fort Collins were chosen from more than 1,600 entries to be among the 100 semifinalists in the magazine’s contest.

The list of semifinalists will be whittled to 10 finalists, and two runners — one man and one woman — will be chosen to appear on the cover. Readers can vote online to pick two reader’s choice winners through Aug. 16.

Jill Howard

As Howard runs the Pikes Peak Ascent and Marathon this weekend, she’ll be thinking about the literal mountain she’s climbing and the figurative mountain she overcame to get there.

In 2010, Howard ran a marathon in 3 hours, 12 minutes and 50 seconds and was training to qualify for the Olympic trials. But then she suddenly seemed to lose all her energy. For two years she couldn’t run for more than 10 minutes and barely got off the couch except to go to work.

Then, in October 2013, a doctor found a baseball-sized tumor in her brain. Another six months and the doctor said it would have killed her.

The tumor turned out to be benign, and 11 months after the surgery, she qualified for the 2016 Boston Marathon.

“After the surgery, I didn’t know if I’d be able to walk straight, let alone run,” said Howard, 44, who lives in Highlands Ranch. “But I just kept getting on that saddle. I just kept going back at it.”

While Howard still keeps the idea of qualifying for the Olympics in the back of her mind, she’s focused on larger goals. She volunteers once a week at the hospital that saved her life and is working with the American Brain Tumor Association to raise awareness about brain tumors.

Howard also is working on a book that she hopes will be a source of encouragement to others. And as she prepares for Boston, she’s focused less on her times and more on what she loves about running.

“Now I’m just so ecstatic to be able to run that I’m just running with a whole different attitude now, a whole different joy,” she said.

Bard Parnell

Following a violent assault that caused a traumatic brain injury, then-21-year-old Parnell was overcome with anxiety. He couldn’t sleep, he could barely eat, and the medicine his doctor prescribed only seemed to make it worse.

“I kind of got to a low point where I remember coming home from work and sitting on the floor and crying,” Parnell recalled.

Then he started running.

It started with a challenge from his mom, who has been running for more than 20 years: If Parnell would run a half marathon with her, she would buy him running shoes and pay his entry fee.

So Parnell threw on some tennis shoes and went on his first run. He only made it a mile before he turned around, but he already felt better. Parnell went running again the next day and the next, and after about a week, he started sleeping again. The anxiety wasn’t completely gone but running worked better than any medicine he’d tried.

More than 15 years later, Parnell, now 37, has completed three 100-mile races. He discovered trail running and eventually ultrarunning after he moved to Fort Collins about 10 years ago.

“Ultras are less about running and more about being out there,” Parnell said. “The majority of ultrarunners just love the mountains, they love the trails.”

Parnell also started his own apparel company, Feed Your Crazy, after being a little annoyed with the general reaction he got after telling others about his long-distance runs — that he was “crazy.” But runners are some of the happiest, healthiest people he knows, Parnell said, so he wants the brand to encourage them to embrace this “crazy” lifestyle.

“I want to show people that it’s OK that we’re a little crazy,” he said.

Amanda Osberg

Four years ago, at her heaviest, Amanda Osberg weighed 235 pounds. Tired of being overweight, she started walking, then running. By the time she had worked up to a 5K, she didn’t want to stop.

Over the course of a year and a half, Osberg lost 110 pounds.

“When I was overweight, I set a lot of limits on myself,” said Osberg, 28, who lives in Littleton. “As I got older, I realized those limits weren’t actually there.”

After discovering her passion for running, Osberg worked to pass it on to the students and teachers at the school in Honduras where she student-taught last year. The school had a track and field team, but the season lasted only for a month and a half. So Osberg started a program where kids could continue to run with her after school during the off-season.

She started a similar initiative for the K-12 school’s teachers and soon had a group of staff members going on morning runs three times a week. Osberg also organized a 5K run for the entire school.

Osberg continued to run on her own as well and, because the women’s running community in Honduras is small, found herself training with some of the country’s top runners. One of them convinced Osberg to run a 50K (about 31 miles) ultramarathon in Costa Rica with her, which she did in May.

After moving to Colorado, Osberg said she isn’t sure she wants to do more ultraraces, although she is training to run in the Denver Rock ‘n’ Roll marathon in October. After that, she plans to focus on half marathons as well as continuing to share her story as a way to encourage others.

“If you want to change your life, you can,” Osberg said. “You just need the determination to do so.”

Jessica Iannetta: 303-954-1510, jiannetta@denverpost.com twitter.com/JessicaIannetta

VOTE Runner’s World cover search: coversearch.runners world.com/gallery