There were no childhood swim lessons, lifeguards or lap lanes for John and Bradford Tatum.

They grew up in 1920s Washington, in a neighborhood just north of Foggy Bottom, when city pools were closed to blacks. Determined to test their fins, the young brothers got resourceful. They taught themselves to swim in the Potomac River, the Reflecting Pool and Georgetown’s C&O Canal.

“It got real hot in the summer,” said Bradford Tatum, who along with his brother has been a competitive swimmer and diver for 20 years, “and I swear, the Potomac was cleaner back then.”

Now, the Tatums — both nonagenarians, lifelong Washingtonians and Senior Games gold medalists — are two of a handful of athletes highlighted in “Age of Champions,” a documentary premiering Saturday at the Silverdocs festival in Silver Spring.

“A lot of documentaries today leave the audience with a tinge of negativity,” producer Keith Ochwat said. “What drew us to the Senior Games was the positivity. These people have an unparalleled zeal for life. When you’re 90 and 100 years old and have endured life’s challenges and still have such a positive attitude, it’s beyond impressive. We felt it was worth a film.”

Ochwat and director Christopher Rufo came upon the idea at a conference for nonprofit organizations in San Francisco. They were representing the Documentary Foundation, which they founded in 2007 to produce and teach film, and were seated next to the chief executive of the National Senior Games Association. Ochwat said it was kismet.

He was surprised to find out how many seniors compete in the games. “This is the best kept secret in sports.”

Every two years, 300,000 athletes 50 and older participate in the Summer National Senior Games and qualifying events, yet few beyond the participants know it exists, Ochwat said. He and Rufo compiled a casting call to the registered athletes and received more than 1,000 responses. They selected five stories and began filming in May 2009.

“The thing that I’d be willing to pat us on the back for is casting,” Ochwat said. “These athletes, these stories, you can’t write stuff like this.”

Along with the Tatums, the film’s stars include a 100-year-old tennis player, a team of granny basketball players and two rival Texan shot-putters. Much like younger athletes, they train hard, set records and maintain high spirits, often in the face of tragedy and loss.

Earl Blassengame, 88, a soft-spoken track and field athlete from north Texas, has just lost his wife of 64 years. At 100, Roger Gentilhomme, whose preferred game is tennis, is the oldest star of the film. He has beaten cancer, coped with arthritis and a hernia, and has lost five inches in height putting him below five feet. After being diagnosed with colon cancer in 2009, Bradford Tatum underwent chemotherapy during the last games (he still competed) and emerged victorious on both fronts.

“Our minds were blown when we started filming,” Ochwat said. “Aging is hard. Winning a . . . gold medal is hard. Beating cancer is hard. Here’s a 90-year-old guy doing all of it at once.”

Although he admits to being less agile after a series of operations, Bradford Tatum still hopes to win, a goal unabashedly shared by all of the documentary’s athletes.

“We’re competitors,” John Tatum said, laughing. “None of this sappy ‘for the team’ stuff. We want medals, preferably gold ones.”

The Senior Games have all the cutthroat trappings of the regular games: trash talk, foul play, hot-blooded rivalries, temperamental coaches, immense anticipation followed by elation and, sometimes, heartbreaking disappointment.

With Senior Games athletes, there is the possibility they will not be around to compete again. That’s an added element of suspense in the film. It is quietly understood that this might be their last shot, making their wins that much more satisfying and their losses that much more devastating. Fearless and persistent, they refuse to let their bodies decelerate or spirits sink.

Befittingly, all of the film’s subjects are gearing up for the 2011 Senior Games in Houston at the end of the month.

“This is my swan song,” Bradford Tatum said. “After this, maybe it’ll be time to give some of the younger 90-year-olds a chance. Maybe.”

“Age of Champions” is one of 108 films representing 52 countries at the weeklong Silverdocs festival. It will be shown at 5:15 p.m. Saturday. For tickets, call 301-495-6720 or visit