A self-described recovering sugarholic named Jack La Lanne appeared on national television in 1951 and encouraged people to get in shape by running in place and doing calisthenics in the living room. Thus, the first U.S. home gyms were born; the first pieces of equipment to outfit them were chairs borrowed from the dining room.

Over the decades, as home exercise routines and equipment have become both more common and more elaborate, they've demanded more space -- and so the home gym, once a luxury, is becoming more common.

"We used to only do them for upper-income homes, but now there is no income barrier on these kinds of things," said Tim Burch, the general manager of the Case Design/Remodeling Inc. office in Chantilly. "A lot of the homes in this area are production homes with huge basements. They're all the same floor space, and the owners are trying to figure out what to do with it so it'll look different than their neighbors."

According to the Sporting Goods Manufacturers Association, about 9.3 million Americans work out on home gym equipment, a number that has been steadily climbing since 1987.

Richard Miller, president of Gym Source, a New York-based chain of specialty stores for the fitness minded that has two branches in the Washington area, said Hollywood had a lot to do with the popularization of home fitness in the 1980s. "It started with the celebrities; we had home gyms in CEOs' homes for years but it didn't mean anything to people," he said. Pumped-up entertainers such as Madonna, Cher and Sylvester Stallone yammered away on talk shows about the benefits of pumping iron, which put well-recognized faces on the power of a good workout.

Fitness rooms started appearing as a matter of course in hotels, apartment buildings and community centers. People who had gotten used to the amenity and then moved into houses or communities without fitness centers began looking around for a spare room, and gym conversion projects got underway.

"We probably do six to eight a year, and I think all of them are done in the basement," said Burch, whose company typically handles extensive remodeling jobs. "The clients are typically driven by lifestyle changes, not return on investment."

While home contracting companies handle basement conversions that include bells and whistles such as changing areas, saunas, spas and decadent bathrooms, the essentials of a home gym aren't so deluxe.

"You need a good amount of open space, so a lot of people do basements," said Phillip Bergman, who has been a personal trainer in the Washington area for 20 years. "You need mirrors, a proper gym floor, a good sound system and a TV."

The gear that goes into the room is generally divided into three categories: strength, cardio and balance. Strength equipment includes free weights, benches and weight machines. Cardio systems include bikes, rowers, ellipticals and treadmills. For balance gear there are balls, beams, bars and boards.

Free weights are the most popular workout tools, but treadmills are traditionally the No. 1 consumer expense item in home exercise equipment. According to the Sporting Goods Manufacturers Association, U.S. wholesale sales of treadmills in 2003 came to about $1 billion.

Prices for home gyms vary widely depending on what goes into them. Rubberized flooring can be purchased in interlocking sections for about $1.25 per square foot. A three-foot by five-foot mirror runs about $50. Equipment prices are all over the map depending on quality levels. But simple bits of gear such as benches, dumbbells and stationary bikes are relatively inexpensive and often can be purchased used.

Richard and Tanya Landry are both in their early forties and have one child, Steven. They are a successful entrepreneurial couple who finished building a large home in Potomac in 2002. The house includes a hot tub, a swimming pool, a basement home theater and an exercise room that was conceived before the first shovel hit dirt.

"When we came up with the design for the house, we knew there was going to be a gym in it," said Tanya Landry. But unlike most home gyms, the Landrys' is on the ground floor, with nice views and a prominent location in the floor plan.

The couple had exercise equipment in the basement of their old house in Silver Spring but were never happy with the layout. "I used the treadmill but it wasn't a pleasant environment. It pointed at a wall and it was a cramped space," said Tanya Landry.

The advantages to an appealing home gym are obvious, assuming you actually use it for exercise. But while a healthier lifestyle is a gimme, don't count on saving money by dropping the family health club membership.

Gym Source's Miller said, "Ninety percent of my customers who have home gyms also have gym memberships." Health club devotees keep going for camaraderie, new techniques and wider choice of activities.

For instance, although the Landrys work out together at home twice a week with a personal trainer, Tanya also drives to a yoga class on the weekends.

Construction contractors, including Burch, think of additions, conversions and bump-outs in terms of jobs that are under or over $100,000, which is a lot of dough to throw at a room that might not get used -- especially when you might not be able to recoup the entire amount if you sell the house.

"The statistics on a kitchen renovation usually tell you that you get 100 percent back in value," Burch said. "Basements are usually under 100 percent return. But we're seeing that rise."

But Burch also sees a built-in safety net. He said, "Once the equipment goes out, you have a room that can be remodeled into a rec room or a movie room. It can very easily be turned into something else."

Tanya Landry works out in her Potomac home's gym with trainer Phillip Bergman. Steven Landry, 5, and mother Tanya do heavy lifting in their home gym in Potomac.