DALLAS -- First, a reality check: Almost nowhere but at a meeting of the Justin Bieber fan club would a 30-year-old, let alone a 22-year-old, be considered old.
In the age-skewed world of elite athletes, though, swimmer Brendan Hansen and gymnast Nastia Liukin are practically elder statesmen. And they're among a sizable group who, by winning a spot on the U.S. Olympic team this summer, will help stretch the upper age limits of what is generally a celebration of youthful athleticism.
Any list of older athletes training for a spot on the 2012 U.S. team has to start with Dara Torres, the 45-year-old who already was the oldest swimmer to compete in the Olympics four years ago and, appropriately enough, wrote a memoir titled, "Age is Just a Number." And she indeed was one of the older athletes whom Hansen, a gold medalist in Athens and Beijing, talked to when he decided to return to competitive swimming after a couple of years off.
"Don't ever wait for anything to hurt," Torres told him, Hansen said Monday at a media gathering hosted by the U.S. Olympic Committee here. "Do things to prevent that from happening. It's worth it because I'm injury-free."
That is indeed one of the keys to extending any sports career, said Michael Joyner, a Mayo Clinic doctor who researches athletes and aging.
"And then it's just staying motivated," Joyner said in a telephone interview.
Joyner said that many athletes don't so much wear out physically as mentally: They just can't face another four years training in the pool, on the track or in the gym. That is something swimmer Michael Phelps, 26, has frequently alluded to, saying he never wanted to be swimming competitively past the age of 30, vowing London will be his last Olympics.
Swimmers in particular should be more immune to the ravages of age, since theirs is a non-impact sport and one largely driven by technique, Joyner said.
According to a USA Today article, the average age of the U.S. Olympic swim team rose from just over 18 in 1972 to nearly 23 in 2008. While this year's team has not yet been selected, should swimmers like Torres, Hansen, Janet Evans, 40, and Amanda Beard, 30, make the cut, they could help counterbalance the average against the likes of phenom Missy Franklin, who recently turned 17.
That is a more common age for gymnasts, especially female ones, whose sport tends to favor the light but powerful sprite.
"It's definitely a race against the clock," said Nastia Liukin, the all-around gold medal gymnast in the 2008 Games who decided last summer to try for another Olympics. At 22, she is already used to being considered old.
"In '08, I was 18, and people said I was over the hill," Liukin said Monday at a U.S. Olympic media event here. "Your career doesn't have to be over at 16."
Still, she said, she realizes the uphill battle she faces, mostly against that clock; it kept running during those two years when she largely abandoned the kind of intense training necessary for Olympic-level athletes. Instead, the glamorous Liukin -- at Monday's event, she wore what appeared to be Christian Louboutin stilettos, their trademark red soles matching her USA polo shirt -- traveled on various promotions and filmed commercials for sponsors.
"As time was getting closer, I knew I would have to hang up everything else," said of her decision last year to try for London. "It hasn't been easy, but at the same time it's been rewarding."
Gymnasts tend to be younger these days because of the specific demands of their sport, Joyner said. "You need tremendous flexibility," he said. "And you don't get more flexible as you get older."
Gymnasts tend to have a "sweet spot" when they are optimally suited for their sport, he said, when their strength-to-weight ratio is ideal. After all, as 17-year-old gymnast Aly Raisman noted, "you're lifting your own body weight."
Finally, Joyner said, injuries are always a factor for gymnasts, something Shawn Johnson can confirm. Although in Johnson's case, her knee was torn up in a 2010 skiing accident. She had surgery, but went back to the gym too soon and re-injured it, taking herself out of commission until early 2011.
Upon her return, the 20-year-old Johnson found what athletes who take a break, by choice or not, often confront: In the interim, a whole swarm of younger athletes has caught up to their level.
Johnson remembers her first day back at a training camp, when, "no joke, I saw eight girls in a row do an Amanar," she said of a 2 1/2 twisting layout on the vault. "I was the only one who did it."
Now, she said, she realizes that she'll have to adjust her approach. "I won't have the most difficulty, but I will be the most consistent and cleanest," Johnson vowed.
Johnson only needs to look in her own gym in Iowa to see the next wave of competitors in the giggling form of Gabrielle Douglas, part of the U.S. women's team that won the world gymnastics title last year. Douglas, whose wide-eyed and cheery personality makes her seem even younger than her 16 years, moved from her Virginia Beach home to Iowa to train with Johnson's coach, Liang Chow.
"I wish there was another year before trials, not just two months," Johnson said. "I wish I was 15, 16 again."