Matthew Centrowitz races to a first-place finish in the 1,500 final at the U.S. Olympic track and field trials in Eugene, Ore. (Andy Lyons/Getty Images)

From Barcelona to London, the past six Summer Olympics have had at least one thing in common: The United States track and field team, which won more medals — and more golds — than any other nation at each, has had trouble getting through the metal detectors en route home.

Matching their usual lofty win totals is far from guaranteed next month when the world’s best athletes descend on Rio de Janeiro. The U.S. Olympic track and field trials wrapped up Sunday, and the American squad headed to Brazil features a handful of familiar names but is also chock full of youth and inexperience.

“There has always been this conversation that has rumbled around about the great fortunes perhaps on a dwindling state in the United States,” said Vin Lananna, the head coach of the men’s Olympic team. “I think this meet today demonstrates this is a heck of a team to make — greatest team in the world.”

The final day of the trials at Hayward Field on Sunday was packed with thrills and surprises, which included Matthew Centrowitz setting a trials record in the men’s 1,500, Allyson Felix falling short in the women’s 200 and 16-year-old Sydney McLaughlin qualifying in the women’s 400-meter hurdles.

With an expected average age of 25.9, this shapes up as the youngest American Olympic track and field team since 1988. It will feature 77 athletes who will be competing in a Summer Games for the first time. Lananna points out, however, that most members of the Rio-bound squad have faced elite international competition and the younger athletes, including three teenagers, could bring added excitement to their debuts.

“I think our veterans will help them along the way,” he said. “I’m kind of excited to see. Who knows what can happen? Our expectations are really high on them. I’m sure there will be pressure on them, just as there is on every other athletes that competes.”

The U.S. team will range in age from 16 to 41 (Bernard Lagat, a five-time Olympian who won the 5,000 meter here), but the group doesn’t necessarily have the Olympic experience of previous American teams, at least on the podium. At the London Games, the U.S. team brought home 28 medals, including 19 gold, the most of any nation. But only 11 of the medalists from the individual events earned a trip to Rio. The women’s team especially is seeing a lot of turnover among its top performers, with only four returning medalists: Felix, pole vaulter Jenn Suhr and long jumpers Brittney Reese and Jenny DeLoach.

The track and field team typically accounts for a good chunk of the United States’ overall medal count — it accounted for more than one-quarter of the country’s total medals in London. In the past century, the track and field haul has ranged from a low of 16 in 2000 to 40 in 1984. But for the Rio-bound squad, some seeds of concern were sown at last year’s world championships in Beijing.

The United States sent 130 athletes to Beijing and brought back 18 medals, including six golds. While no nation had as many total medals, it was still the Americans’ lowest world championships total since 2003. The runners especially struggled. The lone gold by the men’s track team was a relay win, and both squads disappointed in the middle and longer distances, combining to win just one medal in races longer than 400 meters.

All six of the United States’ reigning world champions qualified for the Rio Games and will have their sights set on gold in Rio: Joe Kovacs, shot put; Christian Taylor, triple jump; Ashton Eaton, decathlon; Felix, 400 meters; Tianna Bartoletta, long jump.

Despite concerns from last year’s world championships, this year’s Olympic coaches left these trials feeling good about the talent they’ll be taking to Rio.

“It just keeps getting better and better,” said Connie Price-Smith, the women’s coach. “We have the youth. Track and field’s not going away. We are strong. We just continue to keep getting stronger. They keep getting better, and the older athletes keep lasting longer in the sport.”

One thing that figures to benefit the U.S. track and field team next month: the likely absence of the Russian athletes, who have yet to emerge from a doping scandal that has placed their entire squad on suspension through the Summer Games. The Russians’ last likely hope is an appeal filed with the Court of Arbitration for Sport, which is expected to render a decision by July 21. Russia’s track and field teams won 16 medals, including seven gold, four years ago in London (though at least a couple of those could be soon revoked).

Officials with USA Track and Field were finalizing the roster Sunday night and determining which sprinters would be added for the Olympic relays. On Monday, the USATF high performance team, led by Duffy Mahoney, the organization’s chief of sport performance, will gather to assess the team, forecast each event and plot for all possible scenarios. They’ll come up with a medal projection, a specific target that is usually in the mid-20s.

These Summer Games, though, could be tougher to predict than most.

“There are always surprises,” said Jill Geer, a USATF spokeswoman, “both negative and positive at the Games.”