Gary Hall, Sr. learned to swim at age two, and took to the water right away.
"I found the water exhilarating and I still do today," he says. "The weightlessness, the movement."
Not to mention the swimming competition, which Hall went on to conquer in the Olympics of 1968, 1972 and 1976. Now 61, he still swims three or four days a week.
He has also applied that passion for exercise to helping reduce the childhood obesity epidemic in the U.S.
In 2009, he launched World Fit, a nonprofit affiliated with the U.S. Olympics that promotes youth fitness in schools nationwide. Hall inspires the kids to jog, walk, or run for 40 minutes daily during the six-week program.
Hall recently learned his World Fit program is a semi-finalist in the End Childhood Obesity Innovation Challenge, a competition sponsored by the nonprofit Partnership for A Healthier America.
The partnership was formed in 2010 in conjunction with First Lady Michelle Obama's Let's Move campaign.
The work is cut out for them. Obesity rates in U.S. children have tripled in the past 30 years. Now, one of five children ages six to 11 are obese, according to the CDC.
Hall enlists some Olympic star power to help him introduce the 40-day competition into schools and fire up the kids. "Olympians get up and give a talk about the importance of being fit and healthy," Hall says.
A partial list includes track-and-fielders Willie Banks and Michelle Carter and figure skater Sarah Hughes.
The program has grown quickly. Last year more than 30,000 students in 18 states from about 80 schools participated.
"Our goal is to get to 1,500 schools by 2016," Hall says.
Why 40 days?
"We think that six weeks is long enough to change a habit," he says, intending to transform kids from being inactive to active. A lifetime exercise habit is known to help with weight control.
Those kids who reach 60 miles or more during the program can earn special certificates. Each school gets 25 medals to present to the most deserving students.
After the 40-day challenge, he encourages students to continue the daily walking and log-ins. "A lot do continue," he says.
He's hoping to win the grand prize for innovation. "I would love to," he says, "only because I want to get World Fit recognized."
His competition is stiff. Along with Hall, there are nine other semifinalists. Grand prize is $10,000 along with expert advice on how to grow the idea.
America is invited to vote. The deadline is Feb. 1. To do so, go to the End Childhood Obesity Innovation Challenge Website.