Indeed, there's no specific age
limit for taking part in the Olympic games. Each International Sports Federation sets its own limits.
The youngest athlete competing in Rio is Nepalese swimmer Gaurika Singh, according to the official Olympic News Service blog
; she's 13 years old. Meanwhile, US track and field athlete Meb Keflezighi is 41; Great Britain's Jo Pavey, a track and field athlete, is 42; and Mary Hanna, an equestrian from Australia, is 61.
The age differences have been even more extreme in Olympics past. The youngest known Olympian to take home a medal was 10-year-old Dimitrios Loundras, who finished third in the team parallel bars at the 1896 Olympic Games. There may have been a younger medalist; according to the International Olympic Committee
(PDF), a young French boy was a cox for a Dutch coxed pairs rowing team in 1900. He took part in the medal ceremony and was photographed. But, despite years of research, his name and age remain unknown. He's estimated to be between 7 and 12.
Oscar Swahn, a Swedish shooter, was 72 years old when he competed in his third and final Olympics in 1920. He ended his career with a total of six medals, three of which were gold. To date, he is the oldest medalist in Olympic history.
But how does age affect your ability to compete? It depends on the sport.
The thought of aging concerns some athletes who hope to compete. But, for other top-level competitors, getting older might be to their advantage.
The advantage of age
Take shooting, a sport that requires more mental strength rather than agility.
"Age factor has a big impact, kind of opposite of a lot of your sports, because it's just the knowledge of the game," said Bret Erickson, an American sport shooter who competed in four Olympics. "The prime ages for a lot of your shooters is mid-30s to 40s because experience plays such a big role."
Erickson noted that a little age can help athletes mentally, and they're better able to understand the game. Kim Rhode won her first gold medal in 1996 at age 17, and she's now competing in her sixth Olympics.
Rhode was "a diamond in the rough" as a teen, said Chad Whittenburg, the national junior development coach for USA Shooting, of the five-time medal winner. "When it comes down to crunch time and the pressure is on the line, usually the older, more experienced shooter will reign supreme."
Though the sport does require some physical strength, such as a stable core, it is eyesight and superior hand-eye coordination that allow athletes to continue competing at an elite level.
But in other sports, careers end decades earlier.
The power of youth
In gymnastics, younger athletes are often the most successful: In 2012, medal winners of the individual all-around category were all younger than 18. There are biomechanical advantages in being smaller in the sport. Carrying less weight and being shorter allows athletes to more easily get off the ground and swing themselves around a bar. At 19 years old and 4 feet 9 inches, the United States' Simone Biles is a three-time world champion.
"For the female body to hold up once you get past puberty, it's a battle to maintain that strength to weight ratio," said John Geddert, 2012 Olympic coach and personal coach for 2012 Olympic gymnast Jordyn Wieber.
Gymnastics is unique because there has been much debate and even scandal
surrounding the age requirement, which has gradually increased over the past 40 years. In 1997, the the International Gymnastics Federation raised the minimum age for competition from 15 to 16.
Geddert said there are pros and cons to this requirement, but he thinks the age restriction is too high.
"The sport of gymnastics can easily be accomplished at a very high level at ages 14 and 15. Therefore, some of those athletes miss out on a once-in-a-lifetime opportunity because they might be a year too young when the Olympics come around," he said. "And then to hang in there for another four years is sometimes just impossible in our sport."
There shouldn't be preteens competing, he said, but "within reason, let the best athletes in the world compete on the world stage."
Aly Raisman, the 22-year-old captain of the US women's gymnastic team, is "a rarity," Geddert said.
Even more rare: Oksana Chusovitina, a 41-year-old gymnast competing for Uzbekistan. She has competed in every Olympics since 1992. She took home a gold medal that year, before most of her competitors were born.
"I don't know how it's possible myself," Chusovitina said. "Yes, they call me 'Grandma,' but in competition, we're all equals, whether you're 17 or 40."