Michael Phelps qualifies again: How Olympians are defying age limits

Michael Phelps won the 200 butterfly to qualify for his fifth, and record-breaking, Olympics. Is Phelps an outlier or are Olympic careers getting longer?

Age may no longer be a quick and easy predictor of athletic success.

Michael Phelps’s record-making fifth Olympic qualification on Wednesday night points to a larger trend of athletes having longer Olympic careers.

Mr. Phelps began his Olympic career when he was 15 years old and briefly retired after the 2012 Olympics in London, but, at the age of 31, decided to try again. He is now the first American male swimmer to qualify for five Olympic contests. Phelps isn't the oldest American male qualifier in Olympic history. That would be Jason Lezak who, at 36, qualified for the 2012 Olympic Games.

For women's Olympic swimming, Dara Torres broke records in 2008, when at 41 years old, she became the oldest American Olympic trials swimming champion and the first first American swimmer to appear in five games. She was the oldest swimmer ever to compete in the Olympic Games and didn't go home empty-handed either after winning three silver medals in her events.

In 2012, the oldest Olympian in 92 years competed in London. Hiroshi Hoketsu, an equestrian, was 72 years old when he participated, making him the third-oldest athlete to compete in Olympic history, after marksman Oscar Swahn (1920) and equestrian Arthur von Pongracz. Hoketsu's Olympic career lasted for almost half a century.

In an article about Mr. Hoketsu for The Christian Science Monitor, Takehiko Kambayashi wrote in 2012, "Age doesn't play as much of a factor in equestrian events as in other sports – the US team, for instance, will feature one rider who is 52 and another who is 18...One reason for [Hoketsu's] prolonged competitiveness is his chemistry with Whisper, a 15-year-old mare."

In rowing, where ages of participants in the last Olympiad ranged less widely, an analysis found that the retirement age for multiple gold medalists has risen significantly between 2000 and 2015, from an average age of 24 to 39.

Swimming has seen the same trend over the past 30 years. Matt Barbini, a performance consultant with the US National Team, has found that the average age of Olympic swimmers increased by 4.6 years for men and 3.3 years for women between 1984 and 2012. Mr. Barbini also found medalists to be older by five years for men and by 2.7 years for women.

Athletes in every sport and field have been defying age-old age limits. "Forties is the new 30s for physiological capacity," Scott Trappe, director of the Human Performance Lab at Ball State University, told CNN. "We're going to continue to see people do well into their 40s – no question."

Haile Gebrselassie – the Ethiopian Olympic runner who at age 35 broke the world record for the fastest marathon, a sport whose so-called "peak" age is 25.4 years old, according to a 2012 study at the Institute of Biomedical Research and Sports Epidemiology in France – expects the same success at age 43.

The secret? Athletes like Hoketsu and Gebrselassie simply never stop.

As Mr. Kambayashi wrote, "In the past, to keep himself in top competitive form, Hoketsu maintained a disciplined and ascetic life while living in Japan. He would get up at 5 every morning to go riding for one to two hours before work. He continued the regimen for three decades."

Gebrselassie has the same attitude. "A day without running is not a good day," the running legend told CNN's Human to Hero Series.

While teams of nutritionists, coaches, sport psychologists, and physiologists contribute to long-lasting winning streaks, success is also about joy, said Michael Lohberg, coach to Ms. Torres.

Torres would not continue to be a successful swimmer if she did not enjoy swimming and judiciously use her energy, Mr. Lohberg, her coach of two years, told CNN.