Confronted with the stern stare of Vashti Cunningham, many would buckle at the knees. Lucky for the bar, it doesn’t have knees.

In Portland, Oregon, for the World Indoor Championships, that stare was preamble to a record performance. She charged the high-jump bar, legs like pistons, accelerating and lifting off as if not bound by the laws of physics, as if gravity fails to have the same pull on her. With fluid grace belying the difficulty, she dipped her head and shoulders over the bar before rolling the rest of her body clear.

Cunningham, a Las Vegas native coached by her father, former UNLV and NFL quarterback Randall Cunningham, had placed first in the high jump at the U.S. Track and Field Indoor Championships a week prior, earning a special invitation to the World Indoor Championships in March.

In Portland, she cleared the 6-foot-5 bar with room to spare to take the world indoor title. At 18 years 62 days old, she became the youngest world indoor gold medalist in history, and the day after her historic victory she announced she was turning pro, signing a contract with Nike and forgoing her college eligibility. She was still two months away from getting her diploma from Bishop Gorman High School.

“I take different styles of past jumpers and mix them, so I don’t think I jump exactly like anyone else,” Cunningham says. “All the time people tell me I make it look easy, but I can tell you it’s definitely not easy.”

Cunningham, who stands 6-foot-1, has long been a promising high jumper, but her rise to medal contender in Rio would have been hard to predict a year ago. At the end of her junior season she no-heighted at the Nevada State Championships, failing to register a successful jump. “That just wasn’t my day,” she says now. “I was determined going into that meet, but I really don’t know what happened. I missed my first jump, and then missed the second attempt. By the third attempt I think I was frazzled.”

But Cunningham kept charging forward, jumping her way to a historic season. And at the Olympic Trials in early July, she took second in the high jump, booking her ticket to Rio.

Before terrorizing NFL defenses as a dual-threat quarterback, Randall Cunningham was also a high school high jumper. But injuries pushed him to focus on football, and when he went to UNLV there was no track team. He noticed track ability in Vashti when she was little, and she took to the sport quickly.

“When she was playing flag football at 8 years old, she was running faster than the boys,” Randall said. “She was really good. They put her on offense, and she would run for four touchdowns in a game.”

Combining techniques he learned playing football and through film study of history’s best high jumpers (and Vashti’s own jumps), Randall created a unique training regimen built to avoid injuries and burnout. “I take what I learned during my career and apply that in a way that takes care of her back and knees. There are no squats or power cleans. I’ve designed my own weight program for her, but I don’t want to give away all my secrets.”

Randall is also adamant about re-creating meet conditions. Leading up to the Olympics, Vashti trains at 4 p.m., the hour of her event in Rio (accounting for the time difference). When Vashti mentioned that applause distracted her, Randall enlisted friends and family to clap and cheer during practice so she would get accustomed to the noise. He also taught her that signature stare down for the most pressure-packed jumps, advising her to walk up to the bar for a direct face off.

“Sometimes he mixes the coach and dad roles, and it can be annoying, like if I’m chillin’ on the couch at home and he starts bringing up high jump,” Vashti says. “But I’m used to it. It’s what he’s always done and it helps keep me focused.”

Her mother, Felicity, was a professional ballerina in the Dance Theatre of Harlem, and while she granted Vashti her own share of über athletic genes, Felicity stays out of the coaching and serves as the parent who will discuss “normal things,” Vashti says.

Those genes keep producing track prodigies too. Vashti’s older brother, Randall II, competes in high jump for USC, and her younger sister, Grace, participated in the Junior Olympics in July. Randall says another jumping Cunningham, Sofia, is on the way, but she’s just 4 years old.

All of the Cunninghams will be in Rio to support Vashti, who has arrived at the top of the sport, a moment marked by Nike ads in which she stands shoulder to shoulder with established U.S. stars and fellow young phenoms like Allyson Felix, Colleen Quigley and Skylar Diggins.

“I don’t ever get nervous before meets, but I always want to get my first jump over with,” Vashti says.

It’s after that first jump, when the bar starts to reach and then surpass her own height, that the stare down appears. Don’t blink—her next jump might be the high point of a historic year.