EUGENE (Oregon) • Allyson Felix's dreams of a rare Olympic double came to an abrupt end at the US track and field trials on Sunday.

Her hopes of becoming only the third woman to win both the 400m and 200m at the same Olympics ended in an agonising defeat in the shorter race.

The 30-year-old, the reigning Olympic 200m champion, finished fourth in 22.54sec, just edged out of a top three spot by Jenna Prandini in 22.53. The race was won by Tori Bowie, who stormed home in 22.25, ahead of Deajah Stevens in 22.30.

A disappointed Felix - who had already guaranteed her presence in Rio next month by winning the 400m earlier in the meet - blamed a lack of speedwork for her defeat, as her season was disrupted by a freak training accident in April which left her with torn ankle ligaments.

"I feel disappointed. This whole year - that had been what I was working for and so for it to end here it's disappointing," the reigning 400m world champion said.

"The speed just wasn't there, period. When I give all I have and I run 22.5 it's just not there."

While Felix was left to reflect on her disappointment, high school student Sydney McLaughlin was celebrating becoming the youngest member of the US track team at just 16 years of age.

Sydney, who turns 17 on Aug 7 during the Games, held her nerve to clinch third place in the 400m hurdles in a junior world record of 54.15sec.

The race was won by Dalilah Muhammad, who clocked the fastest time of the year, 52.88. It was around a second faster than her previous best for the event.

Yet the plaudits went to Sydney, who is the youngest woman ever to qualify for the event at an Olympics. "It's a big relief. First day I got here and I had a nervous breakdown," she said. "My coach just pushed me through it."

The Americans will arrive in Brazil with an athletics squad likely to include 77 first-time Olympians.

This is expected to be the youngest US track and field team sent to an Olympics since 1988, with an average age of 25.9.

AGENCE FRANCE-PRESSE