As with whole body vibration, these machines shake the body from the ankles up. The big difference is that the moving and shaking goes on while you're lying down.
How It Works: You lie on the floor (or a treatment table) and place your ankles on top of a small square box that basically vibrates your body from the feet up.
The Promise: The benefits are supposed to include improved metabolism, weight reduction, increased energy, muscle relaxation, increase in cell oxygenation, and stimulation of the sympathetic nervous system. Some proponents say that just five minutes on the Chi machine is the aerobic equivalent of walking for 30 minutes.
Chi machines are also advertised as being beneficial for those with diabetes, fibromyalgia, lymphodemia, and migraine headaches, as well as those who want to tone their muscles and lose weight -- all while lying down for just 15 minutes a day.
What the Experts Say: "This is a totally passive way of supplying increased circulation to a muscle and that's all," says Varlotta. "It will not give you increased strength, and it could never replace exercise done standing on your own two feet."
Quist likens it to the "jiggly belts" used in the 1950s, which simply caused your body to shake.
"I don't think they ever proved scientifically that those belts did anything for weight loss, and I think the effect is similar with the Chi machines," says Quist.
Bryant agrees:"Part of the thinking here centers on the Eastern philosophies of energy centers and those are being stimulated by this movement activity, but I have not seen anything even close to science on that," he says.
He adds that if you just lie on the floor and kick your legs, you would probably get a similar circulatory effect, along with some muscle toning.
Electronic Muscle Stimulators: Ab Stimulating Machines
It's hard to miss the ads for these products -- svelte, toned guys and gals in bikinis, showing off their "six pack" abs, ostensibly delivered courtesy of electronic ab stimulation.
How They Work: You strap on a wide belt wired to a battery. Stimulation is provided by tiny electrical "shocks" delivered at timed intervals, designed to stimulate muscle contractions.