Bronson Hearn-Smith won the Essex Schools final to go to nationals.

David Hearn-Smith recently posted a video to social media for his relatives to see how his teenage kid was doing in track and field.

The clip showed Bronson Hearn-Smith winning a 100-meter race in a schools championship in Colchester, northeast of London—and instantly went bonkers. Track fans reposted it again and again, obsessing in the comments over the bespectacled 15-year-old with moptop hair who sped to the finish line without appearing to strain. His time was 10.68 seconds.

“It’s a bit mad, isn’t it?” David says.

Even with his seemingly casual finish, Bronson’s time, just off his official personal best of 10.65, would have put him on the podium at the state high school championships in track-mad Oregon.

Yet somehow, Hearn-Smith isn’t an outlier. Something unusual—and incredibly fast—is happening with 100-meter teens around the world.

Sorato Shimizu reacts after breaking the Under-18 world record in 10.00 seconds on July 26.

On July 26, Sorato Shimizu, a 16-year-old in Japan, broke the Under-18 world record by finishing a high-school race in 10 seconds flat. At the Texas state high school championships in May, five athletes in the final broke 10.2 seconds. The winner, 17-year-old junior Tate Taylor of San Antonio, set a national high school record with a time of 9.92 seconds. He turns 18 later this year, making him ineligible for the U18 world record, but he did reach the 100-meter semifinals of this week’s U.S. championships.

So what’s driving these turbocharged athletes who aren’t old enough to vote?

One major cause is the relatively recent arrival of super spike shoes, which has helped lower times across the board. But just as significantly, the line between amateur and pro track athletes is fuzzier than ever, according to Ato Boldon, an Olympic medalist turned TV analyst. Prodigies are accessing better coaching, and they’re able to sign endorsement deals, which adds a financial incentive to improve.

“You have high school and youth athletes doing pro workouts, sometimes training in groups with pros,” Boldon says. “So yeah, the results are going to be different.”

Track’s evolution is also helping to grow the list of places producing sprint stars. Late last year, Australia’s Gout Gout ran a 20.04-second 200 meters at 16, faster than Usain Bolt at the same age. Gout later trained with 2024 Paris Olympics 100-meter gold medalist Noah Lyles.

Asia is also on the rise. At the 2021 Tokyo Olympics, China’s Su Bingtian finished sixth in the 100 meters—the first Asian man to reach the final since Japan’s Takayoshi Yoshioka in 1932, according to Olympic historian Bill Mallon. At Rio 2016, Japan won silver in the 4×100 men’s relay, finishing behind only Bolt’s Jamaica.

Family also matters. Shimizu’s parents and older sister have all competed in track and field, which spurred him to try it. His father, a former high jumper, chose his son’s given name of Sorato, which is written with characters that mean “sky” and “jump.”

“I focus on thoroughly practicing various drills to identify my weaknesses and correct them,” Shimizu said on his school’s website.

In Texas, some athletes who might have played the state’s favorite sport in the past are now choosing to stick to the track, where there’s no chance of being clobbered by a linebacker.

“I don’t even play football,” Taylor said with a laugh after his 9.92, a time that would make any college receivers coach salivate. “I’m too fragile.”

Bronson Hearn-Smith takes notably long strides.

Nothing, however, is making a bigger difference than high-quality coaching for kids who already display natural speed.

Hearn-Smith trains at an athletics club under Steve Garnham, who has 30 years of experience coaching young sprinters up to the international level. And although his style looks easy, like he’s loping to the library, it’s profoundly efficient.

“His high knees are amazing,” Boldon says. “That’s another indication that you have younger athletes being exposed to more senior instruction.”

The 6-foot-3 Hearn-Smith takes notably long strides. In the viral video, he takes just under 42 steps in 100 meters—right behind the 41 that Bolt took to set the world record of 9.58 in 2009.

Hearn-Smith looks even more surprising, because he does all of this while wearing glasses. (He’s still not used to wearing contact lenses, his father says.) But the extra accouterment hasn’t held him back. As his father notes, “his running style is so relaxed, he could run with a marble on his head.”

Write to Rachel Bachman at [email protected], Megumi Fujikawa at [email protected] and Yang Jie at [email protected]