An edgy government ad campaign that made exercise cool and helped boost physical activity among school kids is coming to an end this month after a five-year run.

The campaign, called Verb, consisted of hip television ads and quirky marketing efforts in elementary schools that urged kids to find their own "verb," whether it was playing with their friends, hitting a baseball or jumping off a pier into a lake. The commercials, created for the federal Centers for Disease Control and Prevention, promoted exercise as fun and exhilarating, ending with the tagline "Verb: It's what you do."

The end of the Verb campaign comes just as data are trickling in showing that it was surprisingly effective at boosting physical activity among school children. A recent study of more than 2,700 school kids published in the medical journal Pediatrics showed that 9- and 10-year-old kids who had seen the Verb campaign reported one-third more physical activity during their free time than kids who hadn't seen Verb. Among girls ages 9-13, the ad campaign boosted free-time physical activity by nearly 27 percent.

New research on the Verb campaign and a group of 5,000 children will be published next year, and the data show the same "positive trends" for boosting activity levels among school kids, says Lance Potter, senior study director of Westat, a social-science research firm that conducted the studies for the CDC.

Pediatricians and medical groups have sounded the alarm about the lack of activity and poor eating habits of America's school children. About 13 percent of school children are overweight, according to the Surgeon General, who recommends children get at least 60 minutes of moderate physical activity a day.

Even though the ad campaign appeared to be working, Congress last year failed to renew funding for the CDC to continue the program. As a result, Verb will run out of money this month and the television ads will stop airing. The CDC plans to keep the Web site www.verbnow.com up for about a year. So far, the government has invested $339 million in the Verb advertising and marketing campaign.

Part of the problem with Verb is that many adults weren't aware of it. The campaign was specifically targeted at 9-to-13-year-olds, and ads aired around shows like Nickelodeon's "SpongeBob SquarePants." Surveys showed 70 percent to 80 percent of school kids were aware of the Verb campaign, but the effort didn't generate the same excitement among adults.

"There is not a tremendous amount of adult awareness of Verb, but we haven't targeted them," says Stella Kusner, account director on the Verb campaign for Frankel, a Chicago marketing agency. "But without fail, every time we go out to schools or camps the adults and teachers are amazed at the excitement and brand recognition that kids have with Verb."

Verb also got off to a rocky start after critics complained the government was focusing too much on exercise and instead should be trying to improve kids' eating habits to counter the advertising muscle of the junk-food industry. But the CDC has said it didn't want to lecture children about what not to do, and instead wanted to focus on a positive message that celebrated physical activity.

The latest Verb ad campaign has the look and feel of slick ads from sports giants like Nike and Adidas. It focuses on the sounds of active physical play. It begins with a boy running, and then tunes into the beat of his feet against the bridge. Next it's the grunt of a kid hitting a tennis ball, the sounds of kids playing sandlot baseball shouting "hey batter, batter," kids cheering and the clack of the helmets at a pee wee football game, and the sounds of little girls playing "double Dutch" jump rope.

The Verb campaign also included the Yellow Ball, a symbol of kids playing in the sun. The campaign is in the midst of distributing 500,000 yellow balls at schools, camps and family events. Each six-inch rubber ball has a number. Kids are asked to play with the ball and then log on to verbnow.com, fill out a "blog" about how they played with it, and pass the ball on to a friend. The goal is to let kids track where their yellow ball went and who played with it.

Currently there are about 350,000 yellow balls in circulation and 12,600 kids have "blogged" their ball. As direct-marketing campaigns go, the 4 percent blog response rate of the Yellow Ball campaign is "pretty good," says Ms. Kusner.

One of the bloggers is 9-year-old Drew from Monroe Township, N.J. "I shot the ball in the basket, got the rebound and threw it to my mom," he wrote. "Then I threw it all kinds of crazy ways to my mom."

Ten-year-old Peyton from Poland Spring, Maine, got his yellow ball from a brother, who had received it from a friend. "I have had a lot of fun playing with it in my front yard," wrote Peyton. "One day I was practicing my soccer skills with it and the next day I had it in the pool with me. I am now going to pass my yellow ball on to my other brother. This has been fun."

The remaining 150,000 yellow balls will be distributed in September at schools and special Verb events that include obstacle courses for kids to run through with the balls. Although the government will no longer be funding Verb after this month, there have been discussions with nonprofit groups as well as major companies and sporting organizations about ways to continue the Verb concept without government money.

"If no one comes forward it will cease to exist as it is today," says Ms. Kusner. "The good news is we've got a lot of people interested in advancing physical activity for kids."