Allen Rossum makes his living running away from people. It's a job he has been training for since birth.

"I'm the youngest of eight, man," Rossum explained. "I got chased a lot. I had to run to the dinner table."

The people running after the 49ers return man now are just a tad larger than the siblings who pursued him on the playgrounds of Dallas. But Rossum, who turns 33 next month, remains a step ahead.

He scored the first offensive touchdown of his 11-year career last weekend, outracing a defender and diving into the left corner of the end zone on fourth-and-one.

Expect Rossum to stick more with his more traditional return-man role Sunday against the New Orleans Saints. He enters play ranked second in NFL history with 13,572 return yards. (Brian Mitchell, who retired in 2003, is the all-time leader with 19,013.) All that running around isn't just his job, it's also his mission in life. Rossum is on a crusade to get kids around the country to join the chase.

While playing for the Atlanta Falcons, he appeared at the Georgia state capitol as a spokesman for GA House Bill 1013 — the so-called "Recess Bill" — designed to get elementary and middle school students a daily supervised 15-minute break for physical activity.

The effort failed. But not all was lost. Rossum feels as if people started paying more attention to the cause.

"Even when I started, I was ignorant about a lot of the statistics about the percentage of obese kids who grew up to be obese adults," he said. "The rate of Type-2 diabetes in kids right now is staggering, but it can be corrected."

He created the Allen Rossum Healthy Kids Klub and makes regular presentations at schools and camps. He has enlisted celebrity help, coaxing appearances out of R&B star Usher and NBA players Dwight Howard and Jason Kidd.

Anything, Rossum said, "to tempt them to put down the joystick."

Shortly after signing with the 49ers in February, he took his message to a YMCA in San Francisco. Up next month is a trip to Palo Alto to distribute about 500 backpacks filled with school supplies and a DVD he made about healthy living. Simply listening to Rossum explain the presentation is a workout. In the course of the day, he said, he might teach something about proper posture, brushing your teeth, pilates, karate and dancing.

"Then, we pull everybody together for a session called Chef Allen," he said. "We put a ton of food on the table and make simple dishes like cheese quesadillas, fruit salad, trail mix — just simple things kids can make or parents can make simply for kids."

Rossum's message has found an audience. In 2005, he was honored by the National Fatherhood Initiative, joining a list of previous winners that included James Earl Jones, Tim McGraw and Tom Selleck. The 49ers, of course, didn't give him a one-year, $870,000 deal to be a father figure. They wanted a reliable return man to replace the departed Michael Lewis (punts) and Maurice Hicks (kickoffs).

The question was how much Rossum had left in his tank. The winner of the "NFL's Fastest Man" competition at the 2004 Pro Bowl seemed to lose a step in '07, slumping to a career-worst 6.4-yard punt-return average for the Pittsburgh Steelers.

But maybe Rossum's own adherence to healthy living has helped rejuvenate those legs. Heading into play Sunday, he ranks third in the NFC with a 26.5-yard kickoff-return average. Rossum also showed a terrific burst on his 1-yard scoring run.

"He was running about a 4.2 or a 4.3," left tackle Joe Staley said.

It was just the third carry of Rossum's career. The 49ers touted him as just the second defensive back in franchise history to score an offensive touchdown (joining cornerback Mike Holmes, 1975).

But that's misleading: Rossum hasn't actually taken a snap as a defensive back since 2006. He's just listed that way on the 49ers' roster.

"Is he? I asked them to take that off," Coach Mike Nolan said with a laugh. "Nobody listens to me."

Rossum was a cornerback at Notre Dame, where he set an NCAA career record with nine touchdown returns (three interceptions, three punts and three kickoffs). Almost a dozen years later, the chase is still on.

"Some people get a rush from riding motorcycles or diving out of planes," Rossum said. "I get a rush out of returning the ball."