Between the books in 11-year-old Dylan Wilson’s backpack lies the accessory other students at Orchard Grove Elementary School most covet: a plastic necklace with a kaleidoscope of pendants in the shape of shoes.

He has 66 pendants so far, one of the largest collections at a Frederick school that has developed an uncommon yet effective fascination with running.

The school’s “mileage club” started in fall 2009 with the idea of handing out the charms as an incentive for kids to run during recess. But the results have surprised the staff. As kids ran, fitness scores rocketed and disciplinary problems dwindled.

And for whatever reason, test scores rose.

As schools are scrambling for solutions to the growing problem of childhood obesity, this one is drawing praise for finding a simple answer. Nearly all of the 680 students are running laps and wearing necklaces. This month, global corporation Henkel awarded the school $25,000 to build a three-lane, one-fifth-mile track in its hilly backyard.

“This is the model,” said Charlene Burgeson, executive director of the National Association of Sport and Physical Education. “Most kids, their experiences with running have only been in spurts. And here is a club that teaches [students] how to pace themselves [and] gain endurance. And at the end of the day, they can do so much more than they ever imagined.”

Federal data show there are three times as many obese children now than 30 years ago — an issue first lady Michelle Obama seeks to address in her “Let’s Move” campaign. Many corporations are backing educators in search of new ways to inspire children to get healthy. Across the nation, schools are planting vegetable gardens, adding nutrition classes and installing more playground equipment.

Henkel said 2,100 schools submitted entries in the contest that Orchard Grove won. “We were amazed by the number of innovations,” said Natalie Violi, program director for Henkel’s corporate giving.

Two years ago, the Orchard Grove staff just wanted to give kids something to do during recess. Teachers at the time were worried about an increase in fights, verbal and physical. Some also noticed that many students were not playing classic playground games.

“We have kids who come here who don’t know how to play kickball,” physical education teacher Brenda Tarquinio said. “We used to be able to do fun things just having a stick.”

So Tarquinio created a structure for recess. She set up orange cones around the field near the jungle gym. She used Popsicle sticks to help kids tally their laps on a course of five laps per mile. For every 25 laps, she awarded them a small plastic shoe. This granted entrance to the “mileage club.”

The charms became more elaborate: Snowflakes for running in January, shamrocks in March, turkeys in November. Names of members in the marathon club (just over 26 miles, or 131 laps) were posted on gymnasium walls. Then came the 100-mile club (500 laps). The charms became an Orchard Grove fad, akin to friendship bracelets or virtual pet keychains.

Round and round the children went, during lunch. Teachers also joined in, in hopes of encouraging the students. The assistant principal has a necklace. By the end of last school year, 99 percent of students were in the club.

“I started to enjoy running, instead of doing things for the token,” said David Akuokoh, 9, a fourth-grader who has lost about 10 pounds en route to his 33 pendants.

Assistant Principal Marilyn Mathews said that before the club began she would often have seven kids a day sent to her office after lunch. Now she only sees three a week.

The 15-year-old school has long championed the importance of physical activity. Mathews said one reason is a fluke of demographics: The school has 11 percent more boys than girls. It’s not unusual for a teacher to stop a lesson and instruct the students to do five jumping jacks. Of course, girls and boys alike benefit from the exercise.

In the first year of the club, the number of students rated with outstanding cardiovascular health on the county physical fitness exam rose from 12 percent to 20 percent. The share of students who needed to improve on that measure fell from 36 percent to 21 percent.

The Maryland School Assessment in reading and math for 2010 showed a 10 percentage-point increase in school pass rates. Mathews said it was hard to tell how much the running factored into the academic strides. But she noted that administrators had more time for professional development because there were fewer discipline problems and more focused students.

“It really changed the culture of the school,” she said.

Now, when Diana Rabideau’s first-graders return from lunch, they ask teachers to keep track of how much they ran. She obliges, then giggles as she overhears students try to figure out just how many more laps they need until they get a pendant.

“They are mastering math skills,” said Rabideau, who strives to teach addition and subtraction. “When they come back from lunch, they are now so calm and ready to start an activity. And the boys — the boys! — they are reading now.”

Some teachers are moved to tears as they recount the benefits of the running. They talk of students who have lost weight, parents who are grateful their kids are doing something besides playing video games such as Call of Duty: Black Ops, rewards that kids can’t fully articulate but are apparent to every adult in the school.

In the fourth grade, Dylan Wilson often walked with his head held down and needed extra help in class. Then he started to run.

“I discovered something different about myself,” Dylan said.

Then he posted the second-fastest time in the county on the 100-meter dash. Younger kids started admiring his quickness.

He used to come crying to teacher Pamela Bator because he thought he couldn’t do his work. Now, as a fifth-grader, he recently stopped by to show her the A he got on a math test.

“A completely different student,” Bator said. “He has so much confidence. Now the only thing holding his head down is the number of tokens around his neck.”