By CLAYTON PARK

The co-owners of Mieko's Fitness, which recently opened its doors in Lake City, may be young - Mieko Hart graduated from Lakeside in 1987 while her younger brother, Seiji Hart, graduated from Blanchet High in 1989 - but they are both veterans when it comes to the fitness club business.

Their father, Dick Hart, now 72, owned Hart's Athletic Clubs from 1987 until 1998 when he sold the popular chain, which had 10 locations throughout Greater Seattle, so he could retire.

Meiko (whose name is pronounced "Me-Echo") and Seiji (pronounced "Say-Gee"), who grew up in the Bitter Lake neighborhood, helped their dad build up the Hart's chain from the very beginning, with both kids initially helping out part-time after school and during summer breaks.

Upon earning their respective college degrees - Meiko has a B.A. in Math from Occidental College in Los Angeles and a law degree and MBA from the University of Washington, while Seiji has a degree in accounting and finance from the University of Alaska - both returned to take full-time jobs at Hart's. Meiko eventually became executive vice president, overseeing operations at Hart's, while Seiji became the company's sales manager, and later took a similar position at a fitness club chain in Arizona.

In April 1999, Seiji approached his sister with the idea of going into business together by opening a fitness club chain of their own. They opened their first two Mieko's Fitness clubs that year - in Seattle's Magnolia neighborhood and in Edmonds. Their new Lake City club, which will celebrate its grand opening on July 14, is the chain's third.

But rather than duplicate the concept for Hart's, Mieko says she and her brother are taking what they learned from working for their dad and trying to improve on it.

For one thing, Meiko's Fitness clubs are smaller, ranging in size from 9,000 square feet (Magnolia) to 20,000 square feet (Lake City).

Mieko says that she and her brother want their clubs to be community-based, drawing members from a smaller, more focused area of 3-5 miles, as opposed to trying to attract members from throughout Greater Seattle.

Seiji adds that their clubs are geared for the average person, not competitive body-builder types, and that they want even those who don't have experience using fitness equipment to feel comfortable giving them a try.

The club also keeps its memberships on a month-to-month basis, as opposing to trying to pressure people into signing long-term contracts.

Mieko and Seiji say they have worked to try to keep their membership fees as affordable as possible by focusing on offering fitness equipment and not trying to add amenities such as a swimming pool, or basketball and racquetball courts that would increase their overhead. That's not to say that Mieko's Fitness clubs don't offer nice amenities.

In addition to offering several different lines of state-of-the-art fitness equipment, including treadmills, elliptical trainers, stair-steppers, lifecycles, recumbent lifecycles and rowing machines, the Lake City Mieko's Fitness club offers the following features: a free-weight room; aerobic and group classes; a "Cardio entertainment center" that allows members to watch overhead televisions working out; a Kids Club babysitting area that allows members to monitor their children via remote TV; personalized instruction on equipment; and locker rooms with showers and a dry sauna.

Meiko, who serves as the company's CEO, oversees the administrative aspects of the business from her office in Juanita while Seiji, the managing member, oversees the operation of the clubs.

Seiji, who lives in the Bryant neighborhood, just north of University Village, says he and his sister chose former Lake City Market building for the site of their newest club because "it's a dense area with a lot of need for a fitness club and has a wide array of ages, from college age to seniors. We've got some members here who are in their 90s."

He added that they have received a warm reception from the community. "People say they're glad to have a club in the area. We have a lot of members who just walk here," he notes.

Mieko says the great thing about being in business with her brother is that "there's a lot of trust" between them. Both offer different, but complementary, skills, with her background being on the business side of things, while his background is on the fitness and sales side of things.

Mieko says the other great thing about owning a fitness club chain is getting to use the equipment. "I work out a ton now," she says, adding that her husband, Garrett Kruger, an attorney for Microsoft, also enjoys working out as well. "It's fun, which is why we're in the business," she says. "A healthy lifestyle is so important."

While Mieko and Seiji's dad spends most of his time these days traveling and living the life of a retiree, and is not involved in any way with Mieko's, he recently visited the Lake City club to see how things are coming along. Needless to say, he was impressed.

"He's ecstatic about what we're doing," says Miekos of her father. "He's really proud of us that we're doing this on our own and doing it it our way."

The grand opening celebration for Mieko's Fitness in Lake City will take place on Saturday, July 14, starting at 10 a.m. Oldies music radio station KBSG (97.3 FM) will do a live remote broadcast from the club throughout much of the day. The event will include giveaway door prizes.

Mieko's Fitness is located at 12015 31st Ave. NE.