LONDON – On Friday night, the sport of swimming completed the ultimate symbolic relay exchange.
Michael Phelps touched the wall for the final time in an individual event – in first place, naturally. And as he was finishing, in dove the Phelps Generation to carry the sport forward after its greatest champion is gone.
In dove Missy Franklin, age 17, obliterating the field to win the 200-meter backstroke, set a world record, and earn her fourth medal (and third gold) of these Olympics. And in dove Katie Ledecky, at 15 America's youngest Olympian, roaring out of relative nowhere to win the 800 freestyle and break Janet Evans's 23-year-old American record.
Ledecky is a classic Phelps Generation product. A resident of Bethesda, Maryland, not far from Phelps's hometown of Baltimore, she got his autograph on a swim cap in the parking lot of a meet at the University of Maryland – when she was 6 years old. Then she watched him take over the sport from 2004 until now, stretching the boundaries of what a single swimmer can do. She became a phenom herself as a teenager, setting national age-group records at age 14 and 15.
Then lo and behold, Ledecky is getting ready to swim the 800 free in the Olympic finals and there is her idol – fresh from winning his 21st career Olympic medal – offering her a high-five in the ready room and saying, "Have fun out there." So she swims out of her skin and earns a gold medal of her own, dropping nearly six seconds off her best time.
But the Phelps Generation is not just an American phenomenon. It is worldwide.
[ Related: Phelps's mom reveals retirement plans ]
And so in dove South African Chad le Clos, age 20, who finished second to Phelps in the 100 butterfly on this night but will go down in history as the last man to defeat him in an individual race after his shocking 200 fly upset earlier in this meet. Nobody is a more devoted disciple of Phelps than le Clos, who has patterned his entire career after the retiring American.
After the 200, le Clos said he has watched video of Phelps countless times, and has copies of Phelps's epic 100 butterfly win from Beijing in 2008 downloaded on his laptop in seven different languages. As a 17-year-old in 2009, le Clos's sole goal for making the South African senior national team was to swim the 200 in the same heat with Phelps at the world championships.
"I am his biggest fan," le Clos said.
This is what elevates an athlete from great to transcendent: when he elevates his sport by influencing its young participants. The theme at these Olympics is, "Inspire a generation." Michael Phelps, a legend leaving a legacy, has done exactly that. As he splashes into the sunset, he can enjoy the symmetry of watching that generation grow up and move in.
Half of the 12 women's events completed so far at these London Games have been won by girls aged 17 or younger. Franklin won both backstrokes. Chinese 16-year-old Ye Shewin won both individual medleys. And Ledecky joins fellow 15-year-old Ruta Meilutyte of Lithuania as the two youngest winners. Multiple other teens have hit the medal podium.
On the men's side, 20-year-olds like le Clos, France's Yannick Agnel (two golds), and China's Sun Yang (one gold, with another highly likely Saturday in the 1,500 free) have continued the youth movement.
To one degree or another, they are all the Phelps Generation. The sport is riding a wave of popularity and global competitiveness – a wave of Phelps's own creation.
For years, his mantra has been twofold: to improve the stature of his sport and to convince young people that all goals can be reached with enough hard work and ambition. Today swimming is brimming with young achievatrons motivated to be like Mike.
"I'm getting out at a good time," Phelps said. "The sport is going to be fun to watch. I'm excited to see it from the outside. They're going to take over our shoes easily."
[ Video: Full video coverage of the Olympic Games ]
In truth, nobody is ever going to fill Michael Phelps's shoes easily. We've known that since his eight-gold masterpiece in Beijing four years ago, but fresh reminders of that have arrived routinely here in London.
There have been disappointments that underscored how hard it is to be the world's greatest swimmer for eight straight years – a shocking fourth in the 400 IM and a shocking second in the 200 fly. But there have been two brilliant relay legs and two individual gold medals – the first a throwback Phelps performance Thursday to win the 200 IM, and the second his victory in the 100 fly Friday.
His winning time in the 100 was only four one-hundredths of a second faster than what he swam to earn gold in Athens, and it was .63 seconds slower than the winning time in Beijing. His world record of 49.82, set three years ago, was far out of reach.
Yet this was his widest margin of victory of the three Olympic triumphs. He squeaked past teammate Ian Crocker by .04 in 2004 and by Serbian Milorad Cavic by .01 in 2008, Phelps's most memorable race in a career full of them. This time, despite being in seventh place after 50 meters, he won by the relatively comfortable margin of .23 seconds.
"I don't even want to complain about going slower [than in the semifinals] or having a bad turn or finish," Phelps said. "I just wanted the last one to be a win. We can smile and be happy."
That's because Phelps is not swimming for time anymore, not chasing his own uncatchable standard, not relentlessly focusing on improvement. In his final days as a competitor, he's swimming for the reason kids with baby teeth swim in neighborhood meets everywhere: to reach the wall first and win an award for it.
The award here is a gold medal, and now Phelps has 17 of them and 21 medals overall. The likelihood that he will add an 18th gold on Saturday as the butterfly swimmer in a stacked American 400 medley relay is 99.99 percent.
[ Photos: Michael Phelps with his 21 medals ]
America has never lost that race in the Olympics, and it's not about to start now. With gold medalists in the 100 backstroke (Matt Grevers), 100 freestyle (Nathan Adrian), and 100 butterfly (Phelps), and the bronze medalist in the 100 breaststroke (Brendan Hansen), something cataclysmic would have to happen to prevent Phelps from ending his career on the proper level of the medal podium.
"The 400 medley has been such a big race for our country," he said.
Michael Phelps has been such a big figure in swimming for his country, and for the world. Now, as he prepares to leave, he can see the first Olympic ripple effects from the Phelps Generation he inspired.
More Olympics coverage on Yahoo! Sports:
Related Olympics coverage on Yahoo! Sports:
• Video: Will Ryan Lochte compete in Rio de Janeiro in 2016?
• Video: Thanks to Phelps, Ricky Berens's name will be etched in history
• Swimming legend's odd retirement advice to Michael Phelps