In sunny California folks are mighty serious about shaping up—so much so that some have made a high-tech Calvinist ritual out of becoming and staying firm.

In hip Westwood the ultimate fitness experience can be had at Matrix One. From the exposed, high-gloss air ducts above to the pile and tile below, everything is black, white and gray, even the special-order Nautilus machines. The only splash of color can be found in the pink polo shirts sported by the fitness directors, who provide individualized instruction. The decor is minimal by design. "We could have come up with earthy colors, plants and yellow cycles and we'd be just like everyone else," says John Dobbs, one of four owners. Adds co-owner Steven Kates: "We're preaching technology. Our clients are Ferrari drivers, and they're intrigued by high tech."

Which is what they get, and nothing but. No lounge chairs for meat-market mingling, like the popular Sports Connection nearby. No Jacuzzi bath, no potted palms. Yet Matrix One offers all that the committed exerciser needs to justify the $780 annual membership fee: an aerobics room with special floor padding prescribed by an orthopedic surgeon, a state-of-the-art Questar weight room outfitted with water-resistant machinery, a Nautilus room for traditionalists and, for those who earn a living from looking good, a tanning room, a hair salon and pink track lights to give exercisers a graceful glow when they happen to glance in the wall-to-wall mirrors.

"We don't want amenities; people come here to work," says Michael Greenwald, a part owner with Kates, Dobbs and Chasen Chess.

Members seem to appreciate the austere and insular atmosphere. Explains one model: "I got tired of guys coming over to me on the stationary cycles and offering to fix my tire."

Since Matrix One pumped open its doors 11 months ago, the very rich and famous have hit the exercise trail, most recently Gene Hackman, Cheryl Tiegs and Tony Roberts. Matrix One veterans include Alana Stewart, John and Chris Evert Lloyd, Saudi Prince Khaleel Elaimy, Michael Nouri, Sally Struthers, Tatum O'Neal and Arnold Schwarzenegger. "Beautiful people like to hang out with beautiful people," Greenwald muses. "We're gambling that people who drive fine sports cars and own high-rise condos in Beverly Hills would want to make their bodies the equivalent of that life-style."

But while Matrix One may shimmer with futuristic gizmos and lean-and-mean decor ("I'd put a drinking fountain in the workout room," suggests former Saturday Night Live star Laraine Newman), its deeper allure lies in the high physical cost it exacts—the sacrifice that brings corporeal rebirth. Cheryl Ladd adores the Questar "because you can get a burn in your muscles with only half as many reps." And world-class veteran of sweat-and-strain Schwarzenegger observes, "The guys who own Matrix aren't hypocrites. Some places they have some fat guy teaching aerobics. Not here."

In fact, the partners are living advertisements for their spa. "If I'm really honest," the well-muscled Kates modestly admits, "I can tell you that I've turned heads on the street." The four met five years ago at a Westside L.A. Nautilus center, and each contributes a valuable talent to what they call the Team. "Kates is our figurehead of fitness," Dobbs explains. "Greenwald is great for PR work, and Chess is good with women." Dobbs, for his part, coughed up most of the capital.

With this unique combination of assets, the Team plans to open Matrix One-Beverly Hills on March 1. "It will be even classier," Dobbs says. "We'll have gold-card keys for the main door and valet parking." Memberships will range from $800 to $1,500 a year, depending on the program selected.

So on they go, Kates and Greenwald and Dobbs and Chess, punishing the rich, politely excluding the poor, building strong bodies at least 12 ways, and, just like Wonder, making lots of bread in the process.