How One Woman Turned A Personal Summer Running Challenge Into A Global Movement

Kayla Jeter grew up moving. Her father played in the NFL and she followed suit, playing volleyball through middle school, high school, and eventually overseas in Finland. Throughout her childhood playing team sports, running was always viewed as a punishment. It was conditioning that coaches made you do until you passed out or threw up, framed as character-building.

When she moved to Chicago in 2018, she wanted to get to know the city but didn't have a car. So she laced up her shoes and started exploring by foot, the same way her teammates had taught her to explore the forests of Finland. Not only did this help Jeter get to know the city, but it also got her outside and moving her body.

Somewhere along the way, a casual idea took shape: What if I challenged myself to run 100 miles this summer?

Jeter is quick to clarify that running has never come easy for her. "Every run for me still feels effortful," she says. The runner's high people describe, that effortless, time-dissolving flow state, isn't something she says she's reliably experienced.

What she found with running was a challenge. Coming from competitive team sports, she was used to striving for something. When she arrived in Chicago after retiring from volleyball, she was looking for a place to move, a place to push herself, and people to do it with. Running, she decided, could be that thing, at least for the summer.

When Jeter began running, she ran the way she'd trained for sports her entire life: hard, fast, and all out. She was ripping 5Ks on her lunch break in the hot summer sun to make sure she got in her miles each day.

She started talking about the challenge with other people and began forming a little community of runners, mostly consisting of former collegiate athletes who, like her, understood that brand of go-until-you-can't-go-anymore effort. And as she began posting about her journey on social media, including the ups and downs in everything in between, more and more people were inspired to join.

In 2019, things changed for Jeter when her mother received a fatal cancer diagnosis. Her mother had been diagnosed with cancer before, but this time was different.

Jeter recalls sitting by her mom's bedside in March, thinking about the challenge. She didn't feel like she was emotionally prepared to show up in the way she wanted to.

But the community was there. People were looking forward to the challenge. They were holding space for her, openly, knowing what she was going through. And that collective anticipation gave Jeter a reason to get outside.

"Having other people looking forward to and holding space for me really encouraged me to get out and let running be a place where I process not only feelings, but also feel a little bit of a sense of normalcy that I can control the setting that I'm in," she said. "It doesn't have to be for a specific time or distance. I can just go out there and do it."

Jeter's mother passed away in June of that year, just weeks into the challenge that had started in May. And running became something she hadn't expected, a container for grief. A space where she could get out of her head and listen to what her body was telling her instead.

The following year, the world caught up to what Jeter had experienced in 2019. COVID-19 lockdowns brought the same uncertainty, fear, and loss of control that she had navigated through her mother's illness. And she was able to offer her community what they had once offered her.

Jeter draws a sharp distinction between community and audience. A lot of what gets called community online, she argues, is actually fans or engaged viewers. "The word community to me just means something different." Real community, in her definition, is a place where people feel not only welcome but reflected, where they see themselves in the stories being shared.

Jeter believes she built a real community from sharing something different than what many people in the fitness space offer, something closer to reality. She didn't just share aspirational morning routines and picture-perfect workouts, but rather runs falling apart and the ever-changing process of trying to be better every day. She shared what it looks like to be someone who came from a sports background and finds running hard, and is figuring it out in real time.

"I share my experiences and my learnings hoping someone can take from them and apply them to their own life," she says. By making the barrier of entry feel less intimidating, Jeter allows her followers to feel like what she is doing is possible, whether that be making the most of every Monday morning or completing 100 miles of summer.

The first year Jeter did the challenge, it was just 12 people. But over the last 9 years, 100 Miles of Summer has grown exponentially.

The challenge grew from MapMyRun to Nike Run Club to Strava, where it became the only challenge to span more than a month. At its peak on Strava, the 100 Miles of Summer challenge reached over 260,000 people worldwide.

The community has spread outside of Chicago, to Los Angeles, Toronto, and beyond. "We have a crew in Ghana that are hitting the pavement," Jeter says. "We're all over the place."

Now, the challenge even has its own app, which is now in it's third year. Creating the app was "a labor of love", Jeter says. And while her four-person team is still ironing out the kinks, the vision for the platform remains clear. She wants the app to be a space where people can connect, track their miles, and come back every year.

And the app is nowhere near the end goal. Jeter's ultimate dream for 100 Miles of Summer is to partner with park districts and initiatives like Michelle Obama's Let's Move to get families involved. She wants to see parents and kids working together toward 100 miles over the summer, the way kids once worked through summer reading lists to earn a prize at the end.

You clearly don't have to be a runner to do 100 Miles of Summer. The whole point is to hold yourself accountable to getting outdoors and moving.

"There's different ways to approach it. The challenge itself is an invitation for you to get out and hit the pavement, the path, the tread, the trails," she says.

100 Miles of Summer isn't just a fitness program or performance metric. It's a shared practice of showing up for yourself and for others. Whether you walk every mile, run every mile, or do something in between, the point is simply to get outside and move. And to do it alongside people who are rooting for you.

Jeter never promised it would be easy or that it would look a certain way. She showed up through grief, uncertainty, and runs that fell apart. But she was able to do it alongside people who were rooting for her. And it turns out, that's exactly what people were looking for.