Sanya Richards-Ross waves to the crowd after failing to finish in the first round of the 400 meters July 1 at the U.S. Olympic trials in Eugene, Ore. (Patrick Smith/Getty Images)

Every four years, the U.S. Olympic track and field trials anoints the next class of American stars. But away from the medal podium, where cameras capture the joy of the newly coronated, past heroes grapple with emotional goodbyes.

“I didn’t win every time I stepped on the track,” Sanya Richards-Ross said through tears last Friday, minutes after failing to advance in these trials, “but I think people appreciate my heart and the fact that I’m a good person.”

Athletes who have represented the United States internationally and at multiple Olympics assembled in Eugene for one last shot. While a handful of veterans have qualified for the Rio Games, many others discovered Eugene represents the end of the road. Familiar names such as Adam Nelson and Richards-Ross missed out on their last-gasp Olympic bids. Others, such as Carmelita Jeter, Nick Symmonds and Lolo Jones, pulled out in the days before competition even began.

“I feel closure,” said 40-year-old high jumper Amy Acuff, whose attempt for a sixth Olympics came up short.

Every four years, the revolving door spins. Of the 62 track and field athletes who have locked up spots for Rio, 44 are first-time Olympians.

“It’s heartbreaking to see some of the veterans who will not be on the team,” said Max Siegel, the chief executive of USA Track & Field, “which happens all the time. It’s also equally exciting seeing some of the new members making their first team. The mix is really good for me.”

That mix could be especially pronounced in Rio, where the United States could send its youngest track and field team to the Olympics in years.

The average age of the track athletes who have made the U.S. team is 25.8. (Seventeen more events will be contested in Eugene before the full team is decided this weekend.) No American squad has been younger than 26 years old since the 1988 Games in Seoul. Four years ago, the average age in London was 27.4.

For years, the ages crept higher, peaking at 28.5 for the Sydney Games in 2000. Four years later, the Athens Games represented an injection of youth and new faces to the American squad, introducing many young stars to the Olympic stage, athletes who would stick around for years to come: 18-year-old Allyson Felix, 19-year-old Sanya Richards, 20-year-olds Lauryn Williams, Jeremy Wariner and Chaunte Howard (who now uses her married named, Lowe), and 22-year-old Justin Gatlin.

Many members of that team would stick around through Beijing and London. Felix, Gatlin and Lowe have clinched spots in the Rio Games.

“There’s a bunch of young talent coming, just like in ’04 when a lot of the team was young athletes,” said Wariner, now 32. He won two gold medals at the Athens Games but has failed to qualify for the two most recent Olympic teams. “I think that’s what this year might be like. . . . I like to see the veterans still make the team and do good, but at the same time, it’s kind of like the passing of torch and letting them come up and do their thing.”

Alysia Montano reacts after falling in the 800 finals at the U.S. Olympic trials on July 4 in Eugene, Ore. (Kirby Lee/USA Today Sports)

Even though the veterans will generate many headlines in Rio — Gatlin will try to steal Usain Bolt’s crown, while Felix hopes to have a shot at the 200-400 double — the team’s young athletes bring plenty of their own star power.

English Gardner, 24, has posted the second-fastest time in the world this year in the women’s 100. At 18, high jumper Vashti Cunningham will be the youngest American on the track and field team since Carl Lewis in 1980. Clayton Murphy, 21, just completed his junior year of college, and he posted the top time in the men’s 800 meters.

Among the sprinters, Gatlin, 34, will be joined in Rio by 20-year-old Trayvon Bromell and 22-year-old Marvin Bracy.

“There’s a new era of sprinters that’s coming along,” Gatlin said, “and they got a lot of heart, got a lot of guts, got a lot of grit. When it’s time for me to leave, rest assured that I’ll be able to pass the torch onto Trayvon and Bracy and they’ll handle business.”

The trials serve as a crossroads of sorts, veterans leaving the sport and young phenoms bursting onto the scene. Some head toward stardom and others off into the sunset. In the men’s shot put alone, fans at Hayward Field said goodbye to Nelson and Reese Hoffa, both three-time Olympians who won medals for their country in the past.

“I told my dad this morning, I wanted to just make the finals to say just one time in my life that I got to throw with Adam,” said Ryan Crouser, the 23-year-old who won the event and will compete at his first Olympics.

Neither Nelson, 41, nor Hoffa, 38, qualified for Rio.

“This is my fifth Olympic trials, and I feel like I’m 100 years old,” Hoffa said.

While the past and the future competed side by side this week, the squad that heads to Rio next month could feature names and faces who stay on the Olympic stage for a few more cycles.

“It’s interesting to listen to people who are passionate and follow the sport closely say, ‘Wow, there’s a changing of the guard,’” Siegel said. “But what’s really amazing is when you’re sitting with Jackie Joyner-Kersee — there was a Jackie Joyner-Kersee before there was an Allyson Felix. One of the things that makes me incredibly proud is when you look at the system we have and the depth of talent that we have, the one thing you can be fairly consistently sure of is that we’ll have an amazing team of amazing athletes. It’s just, who are the stars?”