Incorporating more movement into our daily lives, health experts agree, is key to battling obesity. The Centers for Disease Control, after all, find one-quarter of adults are almost wholly inactive. We dutifully take note and promise ourselves to get some exercise . . . the very next time we can pull ourselves away from the desk, the couch, the TV, the bed.

Some architects see a solution: homes built to stimulate motion, where fitness is integral to the design. The most visionary of these concepts don't just enlarge on the home gym, a feature in as many as one in five new luxury homes, according to Joan Vos MacDonald's "High Fit Home: Designing Your Home for Health and Fitness" (HarperDesign, 2005). These designs take home fitness to another level -- sometimes literally.

Some projects take a cue from the corporate world, where the idea of using architecture to spur movement has had a head start. Two examples cited: the Robert Wood Johnson Foundation's facility, in New Brunswick, N.J., which deliberately lengthened the walking distance from the parking lot to the front door, and Sprint's new headquarters in Overland Park, Kan., built to accommodate the pedestrian rather than the car.

The high-end concepts featured in MacDonald's book -- including a house with interior and exterior climbing walls; a "stairmaster" house designed to promote lots of climbing; a house whose tennis court flows nearly seamlessly out of a sitting space -- show the degree to which the idea of designing for fitness has moved beyond the commercial realm.

The architect describes this 10-level Lake Michigan home, built for an active family, as "a StairMaster house." Most motion is vertical since stairs, not hallways, connect rooms. A custom-built house for tennis players in northern Connecticut features a smooth transition between outdoor playing court and an indoor bunk room for spectators.A radical interpretation of the house as motion-maker, this guesthouse was built to permits climbing on and through to multiple viewing platforms. Stairs accessible from all levels hug the house's perimeter and open onto the roof.Makeovers can invite movement, too. In Atlanta, one family converted a two-car garage into a family fitness center, complete with climbing wall to a kid-size sleep-in loft space. If you try this at home, consider helmets for safety.A rooftop basketball court crowns a high-end apartment project in Manhattan. One way to spur communal fitness, reasoned the architects, is to give it a dramatic setting.