Will comeback stories rule ’12 Olympics?

Four years before the 2012 London Olympics, two-time U.S. gold medalist Brendan Hansen stood on the Lane 2 starting blocks in Beijing’s Water Cube and took a deep breath.

The 100-meter breaststroke final boasted the fastest field in history: Hansen, the world-record holder. Japan’s Kosuke Kitajima, Hansen’s archrival and the gold medalist in Athens in 2004. Alexander Dale Oen, an up-and-coming Norwegian, and Brenton Rickard, a formidable Australian.

But as Hansen looked down at the lonely black line at the bottom of the pool, a thought crept into his head about the sport that had defined his life: “Am I really still doing this?”

Less than a minute later, he’d lost, finishing a disappointing fourth to Kitajima, who smashed Hansen’s world record. Hansen hugged the winner and stepped from the pool. His mind was made up. After Beijing, he was done.

“Staring at a black line at the bottom of the pool for 26 years — I had no idea who I was outside the pool,” Hansen said recently from his home in Austin, Texas. “I felt like at that moment, that’s all I had. And I put so many other stuff I wanted to do with my life on the back burner. It kind of overwhelmed me.”

The Olympics are about that brief moment of glory, where a lifetime of training boils down to that once-every-four-years window where you either rise to the occasion or you don’t. We celebrate our winners, we forget our losers. Then we move on.

But for athletes who’ve tasted that fleeting glory, life doesn’t necessarily move on. They remember that feeling. And even after retirement, they want to taste it again.

“When the playing is over, one can sense that one’s youth has been spent playing a game and now both the game and the youth are gone,” wrote Bill Bradley in his memoir about playing in the NBA, “Life on the Run.” “What is left is the other side of the Faustian bargain: to live all one’s days never able to recapture the feeling of those few years of intensified youth.”

In the build-up to the next Olympics, which will begin one year from this week, there’s no shortage of athletes who, like Hansen, once decided they were done, only to find themselves missing that rush. That’s why 2012 is shaping up to be the Year of the Comeback.

In the pool is where London’s most famous comebacks will take place. There, you may find Aussie icon Ian Thorpe, the five-time gold medalist who skipped Beijing and took four years off from swimming before announcing his comeback bid earlier this year. You may see freestyler Janet Evans, who won her first gold medals at age 17 in the 1988 Olympics in Seoul and now at age 39 is training for London after 15 years away from competition. You may watch Ed Moses, who won a gold and a silver medal in Sydney in 2000, and who now at 32 would be the second-oldest US male Olympic swimmer since 1924. And you may stare at the chiseled Dara Torres, the American swimmer who won three silver medals in Beijing at age 41 and is aiming for her sixth Olympic Games at age 45.

But the London comebacks may not stop at the water’s edge.

Kurt Angle, who won a heavyweight freestyle wrestling gold medal in 1996, is training for London at age 42. Gymnast Shawn Johnson is giving it a go after tearing her ACL skiing last year, and fellow gold medalist Nastia Liukin is considering doing the same. Rulon Gardner, whose 2000 gold medal in Greco-Roman wrestling contributed nearly as much to his fame as his stint on “The Biggest Loser” where he lost 188 pounds, is mulling a comeback at age 39.

For Hansen, another Olympics was the last thing he wanted after Beijing. Swimming felt like a job, and he wanted a life. So he married his college sweetheart, whom he’d dated for 10 years. He completed his first triathlon, then another. He traveled. He enjoyed the celebrity lifestyle, like running into tennis superstar Andy Roddick and his wife Brooklyn Decker at a sub shop in Austin. For the first time in his life, when friends asked him to go on a camping trip, or to a concert, or to hang out on the coast, Hansen said yes instead of begging off because he had eight miles to swim the next day.

And for more than two years, he didn’t set foot in a pool.

Then, this past January, Hansen was coaching high schoolers at a swim clinic in Florida. They weren’t listening to his instructions, so he jumped in and showed them. One day in the water became two days, two weeks, two months. His wife could see a difference in him, and she told him that if he didn’t try for another Olympics, he’d regret it the rest of his life. He hooked back up with his coach at the University of Texas, former Olympic coach Eddie Reese, and last month finished second in his first competitive meet since Beijing.

“I had to go to that place to get to this one,” Hansen said of his time away from his sport.

“We’re 12 months out from the Olympics, so I have a finish line in front of me. And I know if I don’t come back and try and make this Olympics, I would regret it. When I’m 40 with two kids, sitting on the back porch, grilling with my buddies, I would regret it.”

America loves a comeback story, from John Travolta in Hollywood to Meat Loaf in rock music to Michael Jordan in the NBA. Olympic history is filled with them.

Longest time off between Olympics? That’d be Japanese dressage rider Hiroshi Hoketsu, who finished 40th for show jumping at the 1964 Summer Olympics in Tokyo, became a successful businessman, then returned 44 years later for the 2008 Summer Olympics in Beijing at age 67. He finished 35th.

Eduardo Prieto Lopez of Mexico fenced in the 1932 Summer Olympics in Los Angeles at age 20, then competed in sailing 32 years later. Gymnast Lucien Demanet of France won an individual bronze in the all-around in the 1900 Summer Olympics in Paris then returned 20 years later at age 45 to win a team bronze in Antwerp.

The most famous comeback attempt was American swimmer Mark Spitz, who tried to come out of retirement at age 41, 20 years after winning a then-record seven gold medals in Munich. He fell two seconds short in his attempt to qualify for the 1992 Summer Games in Barcelona.

Bill Mallon, who is co-founder of the International Society of Olympic Historians and a former professional golfer, remembers asking another retired golfer whether he missed the game.

“He said, ‘I miss being nervous on the first tee,’ and that was a perfect explanation,” Mallon said. “You miss the feeling of this being important, that this matters, that feeling in the pit of your stomach.”

David Wallechinsky, an NBC Olympics analyst and author of “The Complete Book of the Olympics,” was wowed by Dara Torres’ comeback in the 2008 Olympics. But his favorite Olympic comeback came 60 years before that in a Hungarian shooter named Karoly Takach, who was a member of the Hungarian pistol shooting team that won the 1938 World Championships.

“Shortly thereafter,” Wallechinsky said, “he was in the military like all of the shooters in Hungary at the time, and a grenade blew up in his shooting hand, his right hand, and completely shattered his hand. Then World War II happened. Meanwhile, over a period of 10 years, he retaught himself to shoot with his left hand. He came back in 1948, his first Olympics, and he won a gold medal and set a world record — all with his other hand.”

Cael Sanderson’s comeback won’t have the drama of a Karoly Takach or even a Dara Torres. Instead, the 2004 Olympic gold medalist in freestyle wrestling is preparing quietly in State College, Pa.

At the Lorenzo Wrestling Complex at Penn State University, where Sanderson coaches the team that won the 2011 NCAA championship, the 32-year-old frequently wrestles with his team in practice. He stays in shape with workouts five days a week. But the first time he stepped on the mat for competition since Athens was last month in the world team trials.

“It was a little strange,” he said.

Life has changed a lot since his taste of Olympic fame. He’s busy. He has two sons now, ages 1 and 4. He worries about prioritizing his time between his family, his coaching job, and his training schedule. His body doesn’t recover as quickly after workouts, and wrestling workouts — combining explosiveness with endurance — aren’t easy. He jogs, he lifts, he wrestles, he does three sets of weighted pull-ups wearing a vest that weighs as much as 100 pounds.

So why give it another try after already winning gold?

“I just like competing and I see that those days are quickly passing, and if I’m going to ever compete it’ll have to be right now,” Sanderson said. “That’s why I thought, ‘Why not?’ I want to do the most I can with ability I was given. I’m not sure if I did that or not.”

When he sees his name alongside other Olympians gunning for a comeback, Sanderson sighs. He doesn’t want to be on a list of people who just can’t let it go. He feels he can still compete at the highest level, even if he’ll be among the oldest men on the mat. Like all these athletes looking for one more taste of Olympic glory, Sanderson says this is no publicity stunt. This is for real.

“I’m not trying to qualify for the Olympics,” he said. “I wanna win.”