This is a story about Courtney Frerichs, who turned in one of the surprise performances of the Tokyo Olympics. But really it is a story about mantras, because who Frerichs is and what she managed to accomplish this summer are all about the words she has been repeating to herself for years.

We are not talking about mantras in the ancient sense, the chants (“Om”) that are often associated with yoga and meditation practices in modern life.

We are talking about the words and phrases that Frerichs, 28, has spoken both silently and out loud thousands of times. Words that gave her the confidence to run from the front in the 3,000-meter steeplechase in Tokyo, and to hang on through the end to capture the silver medal in a race in which even running nerds gave her little chance of reaching the podium.

“I love these words and phrases because usually they start in practice or in conversation,” Frerichs said of her mantras this week, while enjoying some rest at her parents’ home in Missouri. “It’s very organic.”

Do mantras really make you faster? No one can say they will make you slower. Who doesn’t like to hear a few words of self-reassurance in difficult moments? A 2015 study in the journal “Brain and Behavior” concluded that subjects who repeated a mantra displayed decreased brain activity, allowing for increased focus and relaxation, qualities that come in handy when trying to run the race of your life.

And if a runner believes that something helps make her stronger or faster, it very well might.

Now, a few important notes about Frerichs.

She grew up in southwestern Missouri, where in high school she split time between gymnastics and running. She attended the University of Missouri-Kansas City, which is hardly Oregon or Arkansas in terms of running success. She spent her final year of eligibility at the University of New Mexico, where she helped lead the Lobos to the 2015 N.C.A.A. cross-country championship.

She won the silver medal at the 2017 World Athletics championships in the steeplechase, but she has always seemed to exist in the shadow of Emma Coburn, a fellow American who was the 2016 Olympic bronze medalist and the 2017 world champion in the steeplechase.

Frerichs said her first exposure to mantras came in college at New Mexico, where her coach, Joe Franklin, constantly reminded his athletes that their season-long quest for a championship in 2015 was about the journey rather than the destination.

“That was really defining for us,” she said. “We were the favorites but we were never thinking about nationals. We were always thinking about the step we were in.”

Franklin would frequently recite four words to the team: Expect nothing. Achieve everything.”

Those words were in Frerichs’s mind during the first minutes of the national championship race, when the team started slowly but worked together to win.

She also had it in her head as she embarked on her pro career in 2016, beginning with a shot at qualifying for the Rio Olympics. She made the team, and qualified for the Olympic final, finishing in 11th place. It was a solid debut, especially for a 23-year-old, but she left with the nagging sense that she had played it too safe instead of running as if the race might be the last of her life.

The next year as she prepared for the world championships, a new quote caught her eye: “Be fearless in the pursuit of what sets your soul on fire.”

From that moment on, “fearless” was her mantra. She said it as she started workouts, as she struggled through them, and as she battled through races. She found a temporary tattoo with the word “fearless” at a market in Park City, Utah, and slapped it on her wrist.

By race day at the 2017 world championships in London, she had a plan to run with the lead pack. She followed it and won the silver medal behind Coburn.

In 2018, her coach, Jerry Schumacher, kept telling her, “Let yourself run.” To Frerichs, that sounded like both good advice and poetry. It became her next mantra.

The words were in her head on the final lap of a stacked race in Monaco in July of that year.

“The words allowed me to relax and execute that lap instead of forcing it and getting all tight,” Frerichs said. She broke the American record, completing her signature event in 9 minutes, .85 seconds.

Something strange happened next. Frerichs got away from the strategies that had launched her career.

She battled injuries. She stopped seeing the sports psychologist who had helped her believe in herself, and grew frustrated when her career did not progress on a linear continuum. In 2019, she had no mantra. She finished a disappointing sixth in the world championships.

“I started to let the anxiety of pressure to perform push me down the road to perfection,” she said.

As the pandemic wiped out most of the 2020 season and forced the rescheduling of the Tokyo Olympics, Frerichs began to doubt her place in the sport while battling a hamstring injury.

She decided to return to what had succeeded in the past. As she worked with a new therapist, the word “belong” kept coming up in their conversations. It seemed to sum up what Frerichs most wanted to feel, in her life, in her career and when she was racing. There was the mantra. And she found some temporary “belong” tattoos, which went right on her wrist so she could see the word whenever she needed to.

With each race, she began to live up to what she wanted to be — a runner who could go to the front of the lead pack and belong there.

At the Portland Track Festival this spring, Frerichs went to the lead with a mile to go, making virtually the same move she would make in Tokyo two months later. She was practicing putting herself in the front and controlling the race.

“You need to be able to make the race what you need it to be to be successful,” she said.

Sounds like the making of another mantra. Run with it.