Fitness vibration plates popular but may be risky, experts say

What if you could burn fat while shaking a martini?

Actually, it's your body that shakes like a martini on a new type of fitness machine that's generating lots of buzz and celebrity use. Even NASA has tested the concept.

These machines use vibrations to tone muscle and claim to do it faster. Aggressive promoters also say the equipment improves flexibility and strength, reduces pain and stress, builds muscle and reverses osteoporosis.

However, researchers warn of possible injuries ranging from back pain to cartilage damage. One even warns that the high-powered jiggling might harm the brain. They say the science is thin and too little is known about the long-term effects of such powerful vibrations.

Still, NASA is studying vibration as a possible tool for reducing muscle atrophy and bone loss during astronauts' long, weightless trips in space.

Trainer Michela Rossi instructed Amy Allen as she exercised on a Power Plate fitness machine at the Power Plate Institute in Chicago. The Power Plate vibrates 20 to 50 times a second in three directions, increasing g-forces on the body, and according to the Northbrook, Ill.-based company, raising the effectiveness of lunges, squats and other exercises done while standing on it. (CHARLES REX ARBOGAST ~ Associated Press)

And users of the equipment love the sensation and the quick workout. Workout times are reduced by two-thirds, advocates say, a claim that appeals to busy professionals, mothers of young children and just about anyone who shuns exercise.

"I feel kind of tingly and a little like I got off a ship, kind of shaky but in a good way," said Amy Allen, a 40-year-old working mom in Chicago, after a 25-minute workout on the Power Plate, one of the higher-end brands. "I'm hoping this is the solution to help me get that extra weight off."

However, Bruce Blankenship of Cape Girardeau, a 56-year-old member of HealthPoint Fitness Center, cannot imagine using such equipment.

"I've never tried it, but I don't see how it could be as good as lifting weights or other types of exercises," he said. "It seems like you could get some organ damage from using the machine, and really it seems to me they just brought them back for more money."

The Power Plate vibrates 20 to 50 times a second in three directions, increasing g-forces on the body, and according to the Northbrook, Ill.-based company of the same name. The company says that raises the effectiveness of lunges, squats and other exercises done while standing on it.

The workout is not aerobic; it's more like weightlifting without weights.

Fitness trainers love them, but some users don't like the fact they can't read or watch TV while working out on them, said Craig Bradley, general manager of Holmes Place, an upscale Chicago health club that has four Power Plates.

Doubts also stem from memories of the belt vibrators popular 50 years ago.

"If they make a newer model that is a spin-off of the older version, who knows how popular that could be," said HealthPoint Fitness Center personal trainer Jasper Crites. "However I don't see anybody picking it up and using it, especially not around here and with the modern equipment options we have."

Some researchers are also concerned that high-amplitude vibration can be dangerous over time since it can send jarring waves throughout the body, said Andrew Abercromby, a researcher at Johnson Space Center.

"I believe, and I think quite a few other people believe, the jury is still out on it," Abercromby said.

HealthPoint rehabilitation therapist Jason Emenderfer said the machines are not a good option for those looking to come back from an injury.

"I'm really not familiar with any health benefits related to using this machine," Emenderfer said. "From a rehab standpoint, I can't see this as an option or being used."

Others have been won over, though.

"I think the machines are as good as the imagination of the person using them," Bradley said.

Staff writer James Samons contributed to this report.