An increasingly sedentary lifestyle and a diet of high-fat, super-sized food has caused the childhood obesity rate to more than double over the past decade to 13% of the total U.S. kids population, according to the U.S. Centers for Disease Control and Prevention. In addition, the U.S. surgeon general estimates that up to 70% of overweight children will grow up to be overweight or obese adults.

Statistics like these have triggered a new toy trend, as a wave of pint-sized gym machines and fitness kits is turning working out into child’s play.

L.A.-based Sport Fun is expanding its line of brightly-colored, foam-covered exercise machines for the four to eight set. Last year, the company launched its Start Pedaling Fitness Cycle (US$89.99), Start Walking Treadmill (US$99.99) and Start Lifting Weight Training System (US$69.99), a kid-friendly weight bench made of foam-covered metal, with one barbell and four free weights. The line’s reception at market was stronger than expected, says Sport Fun CEO Karen Myers Mettel, achieving a 90% sell-through rate at both mass and specialty retailers.

Sport Fun has decided to add two more SKUs to the line in June with the Start Climbing Stepper (US$69.99) and the Start Gliding Air Walker (US$79.99), which works like an elliptical trainer, but moves back and forth rather than in circular motions.

This year, the company plans to broaden its distribution channels and possibly roll out a line of accessories. ‘There’s so much concern about children’s health & fitness and obesity right now,’ says Myers Mettel. ‘People are finally addressing the issue, and this is just another tool in parents’ bag of tricks for getting their kids to be healthy.’

Capitalizing on a fitness trend that boasted as many as 18 million adult participants in the U.S. last year, both Sport Fun and West Bloomfield, Michigan’s Yoga Years have come up with kid-sized yoga kits. The Yoga Years Yogateers kit (US$39.95), developed for kids four and up, will hit shelves this month in mass market, specialty and catalogue retailers. The kit includes a scaled-down yoga mat with poses printed around the border, a carrying case, and a deck of cards and spinner so kids can play yoga-themed games. Yoga Years president Barbara Swaab says the response to Yogateers at Toy Fair in New York was ‘beyond expectations’ – particularly from the educational sector. The company plans to capitalize on that interest by putting together a kit for use in the classroom. Swaab and company VP Julie Levinson – who are both yoga instructors – are working with several schools to launch in-school yoga programs.

Yoga Years is currently in production on an instructional video that will be bundled with the kit in about three or four months. The company is also waiting for patents on a line of teen and tween yoga products, and will be bringing out larger-sized kits geared to older kids in the fall.

Sport Fun’s Yoga Divas line is targeted at six- to 12-year-old girls who want to emulate their older sisters or mothers. An instructional video – taught by three 10- to 13-year-old Yoga Diva instructors and incorporating lots of music and dance – is included in almost every set, along with activities and fashion accessories. ‘Kids don’t want lectures and instructions when they have free time; the main thing is it’s got to be fun,’ Myers Mettel says. To fill that need, the Ultra Yoga kit (US$19.99) features a mat that transforms into a tote, a yoga block that doubles as a jewelry box, a pilates ball, a sweat band that makes a bracelet, a belly chain, a headband, a poster and a Yoga Divas video. The Funky Dance, Sassy Yoga, Hip Hop and Cool Flex kits range from US$7.99 to US$14.99.

The line is only targeting girls right now because more girls are into the activity than boys, and because it ties in to fashion. But Myers Mettel doesn’t rule out the possibility of a boys line in the future if the market demands it.