A Grass Valley, California, startup called GameRunner has invented a novel way of navigating first-person shooter games like Halo with a treadmill. Its First Person GameRunner is a manually powered treadmill that plugs into a PC's USB port. As a player walks, the treadmill measures the motions optically and translates them into corresponding movements within the virtual action. A set of handlebars are used for steering, with trigger buttons for firing and other in-game actions. The GameRunner is coming in the first quarter of 2009 for $495, but Olympic gold medalist swimmer Erik Vendt already owns a prototype.

Another product, Gamercize, lets players plug a power-stepper into any videogame console, including Microsoft's Xbox 360, Sony's Playstation 3, and Nintendo's Wii, so that moving in a game is a matter of pumping your feet rather than flicking your thumbs.

"The Wii has had a huge impact," says Terry Grim, co-founder of Grass Valley, California–based KickStart Fitness, which makes the product. "People are starting to realize that playing videogames doesn't mean sitting on your rear end anymore."

Rosemary Lavery, spokesperson for the International Health, Racquet & Sportsclub Association, a trade group that represents more than 9,000 clubs and suppliers in 78 countries, says exertainment is not just a way to help consumers stay in shape, but a means to give gyms a contemporary makeover.

"It makes working out more of a modern experience," she says. "Games get new people in—the generation who grew up with technology and are used to using it in everything they do."

And there's good news for those working out on the Wii at home. In July, the American Council on Exercise announced the findings of a report on the Nintendo Wii by the University of Wisconsin's La Crosse Exercise and Health Program. The study found that gamers burned up to 216 calories per half hour in games such as Wii Tennis and Boxing.

But while the titles increased heart rate and oxygen intake during gameplay, they fell short of the real thing, concluded Cedric Bryant, Ph.D., chief science officer of A.C.E. "While they have managed to get traditional gamers off the couch and our results show that Wii Sports offer more of a cardio benefit than sedentary games, we believe there is no substitute for the real sport," he said. Oh well, back to the gym.